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kanski- frcophth part 2 > Cornea > Flashcards

Cornea Flashcards

1
Q

How are nutrients supplied to the cornea?

A

Aqueous humour

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2
Q

What layers does the trigeminal nerve innervate of the cornea (plexi)?

A

A subepithelial and a deeper stromal nerve plexus are supplied by the first division of the trigeminal nerve.

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3
Q

Vertical and horizontal dimensions of the cornea?

A

11.5 mm vertically and 12 mm
horizontally.

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4
Q

Average CCT?

A

540microns

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5
Q

Layers of the cornea (superficial to deep)?

A

Epithelium
Bowman layer
Stroma
Descemet membrane
Endothelium

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6
Q

What is the corneal epithelium composed of?

A

Single layer of columnar basal cells attached by hemidesmosomes to underlying basement membrane
2 layers of squamous surface cells
outermost cell surface has microplicae and microvilli causing attachment of tear film and mucous.
Corneal stem cells at limbus palisades of Vogt

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7
Q

What is the Bowman layer composed of?

A

acellular superficial layer of the stroma formed from collagen fibres

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8
Q

What is the corneal stroma composed of?

A

90% of corneal thickness.
Regularly orientated layers of collagen fibrils with interspersed modified fibroblasts (keratocytes).
Maintenance of regular arrangement and spacing of collagen fibrils gives corneal treansparency.
Stroma scars, does not regenerate

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9
Q

What is the descemet membrane composed of?

A

lattice of collagen fibrils.
Anterior banded zone deposited in utero and posterior non banded zone laid down throughout life by endothelium. Has regenerative potential

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10
Q

What is the corneal endothelium composed of?

A

Monolayer of polygonal cells. Maintain corneal deturgescence by pumping out excess fluid of the stroma.

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11
Q

Corneal density in a young adult and rate of decreasing density?

A

3000 cells/m2

decreases at 0.6% per year
At 500cells/m2 corneal oedema develops

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12
Q

What are PEE’s and what can you tell by the distribution?

A

tiny epithelial defects that stain with fluorescein and Rose Bengal.
An early sign of epithelial compromise.

Superior stain-vernal disease, chlamydial conjunctivitis, FES, mechanically induced keratoconjunctivitis
Interpalpebral- dry eye, UV keratopathy
Inferior- chronic blepharitis, lagophthalmos, eye drop toxicity, aberrant lashes, entropion
Diffuse- viral conjunctivitis, eye drop toxicity
Central- prolonged CL wear

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13
Q

What are the causes of Punctate epithelial Keratitis (PEK)?

A

Appears as granular opalescent swollen epithelial cells with focal intrepithelial infiltrates.
Causes by adenoviral, chlamydia, molluscum, HSV/HZV, Thygeson superficial punctate keratitis

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14
Q

What are the causes of Subepithelial infiltrates?

A

Tiny subsurface foci of non staining inflammatory infiltrates. Severe adenoviral keratoconjunctivitis, HZK,Marginal keratitis, Rosacea, Thygeson superficial punctate keratitis

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15
Q

What are the causes of corneal filaments?

A

Strands of mucous admixed with epithelium at one end stain well with Rose Bengal. Dry eye commonest cause, others neurotrophic keratopathy

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16
Q

What are the causes of epithelial oedema?

A

Loss of normal corneal lustre. Tiny epithelial vesicles are seen. Bullae form in moderate/severe cases. Cause is usually endothelial decompensation but can follow acute IOP elevation

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17
Q

What causes superficial corneal neovascularization?

A

chronic ocular surface irritation or hypoxia as seen in CL wear

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18
Q

What causes a corneal pannus

A

Superficial neovascularization accompanied by degenerative subepithelial change

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19
Q

What is a corneal infiltrate?

A

yellow or grey white opacities located within anterior stroma associated with limbal or conjunctival hyperaemia. Stromal foci of acute inflammation composed of inflammatory cells.

Suppurative keratitis is caused by active infection with bacteria/fungi/protozoa and occasionally viruses

Sterile non infectious keratitis is due to an immune hypersensitivity response to antigen as in marginal keratitis and CL wear

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20
Q

What is corneal ulceration?

A

tissue excavation associated with epithelial defect with infiltration and necrosis

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21
Q

What is corneal melting?

A

tissue disintegration in response to enzymatic activity with mild or no infiltrate eg PUK

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22
Q

What are the causes of corneal Descemet folds?

A

Striate keratopathy. May result from corneal oedema. Caused by inflammation, trauma, ocular hypotony

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23
Q

Infective vs Sterile corneal infiltrates?

A

Infective- larger, rapid progression, epithelial defect present and large, mod-severe pain, purulent discharge, single infiltrate, unilateral, severe AC reaction, often centrally located, extensive adjacent corneal reaction

Sterile- smaller, slow progression, small epithelial defect/no defect, mild pain, mucopurlent discharge, multiple infiltrates, bilateral often, mild AC reaction, more peripheral location

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24
Q

What is a Descemetocoele?

A

A bubble like herniation of descemet membrane into the cornea plugging a defect that would otherwise be full thickness

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25
Q

What is the Seidel test?

A

demonstrates aqueous leakage. A drop of 1% or 2% fluorescein is applied to the surface of the eye. Using a slit lamp the cobalt blue filter is used to detect a change in
colour from dark orange to bright yellow–green secondary to localized dilution at a site of leakage.

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26
Q

What is specular microscopy?

A

the study of corneal layers under very high magnification (100 times greater than slit lamp biomicroscopy). It
is mainly used to assess the endothelium, which can be analyzed for cellular size, shape, density and distribution.

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27
Q

What are the indications for specular microscopy?

A

1) Evaluation of the corneal endothelium functional reserve prior to intraocular surgery.
2) Donor cornea evaluation
3) Demonstrate corneal pathology eg guttata, descemet membrane irregularities, posterior polymorphous dystrophy

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28
Q

What is corneal topography?

A

Used to image the cornea by placing a series of concentric rings of light on the anterior surface, constituting a Placido image. Reflected light is used to produce a detailed surface map

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29
Q

What are some methods of controlling corneal infection/inflammation?

A

Antimicrobial agents- Broad spectrum initially, then as per cultures
Topical steroids- use with caution as can promote replication of some microorganisms eg HSV, fungi.
Systemic immunosuppressive agents-useful in autoimmune disease

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30
Q

What are some methods of corneal epithelial healing promotion?

A

1) Reduction of exposure to toxic medication/preservatives
2) Lubrication/taping lids shut
3) Antibiotic ointment prophylaxis
4) Bandage CL
5) Surgical eyelid closure for persistent epithelial defects/non healing ulcers.
6) Botox injected into levator muscle to promote ptosis.
7) Gundersen (conjunctival) flap
8) Amniotic membrane patch grafting for persistent unresponsive epithelial defects
9) Tissue adhesive (cyaoacrylate glue)- seal small perforations
10) Limbal stem cell transplantation for stem cell deficiency eg chemical burns/cicatrizing conjunctivitis
11) Discontinue smoking

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31
Q

Which organisms can penetrate an intact corneal epithelium?

A

Neisseria gonorrhoeae,
Neisseria meningitidis, Corynebacterium diphtheriae Haemophilus influenzae

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32
Q

What are some common pathogens causing bacterial keratitis?

A

P. aeruginosa- Gram negative rod bacillus. Over 60% bacterial keratitis

S. aureus- common Gram +ve coagulase +ve commensal of nares/skin/conjunctiva. Keratitis presents with well defined white/yellow white infiltrate

S. Pyogenes- Gram +ve commensal of throat and vagina.

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33
Q

What are some risk factors for bacterial keratitis?

A
  • CL wearing extended. Soft lenses increased risk over gas permeable.
  • Trauma- refractive surgery LASIK linked to atypical mycobacteria. Consider fungal infection as well
  • Ocular surface disease- Herpetic keratitis, bullous keratopathy, dry eye, chronic blepharitis, trichiasis, entropion, exposure, severe allergy.
  • Other factors eg immunosuppression/diabetes/vit A deficiency
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34
Q

Clinical features of bacterial keratitis?

A

Epithelial defect with larger infiltrate and circumcorneal injection
Stromal oedema, descemet folds, anterior uveitis, with hypopyon. plaque like KP’s on endothelium
Chomesis and eyelid swelling in mod-severe cases
Severe ulceration may lead to descemetocoele formation mainly in pseudomonas infection.
Scleritis can develop
Endophthalmitis rare in absence of perforation
Improvement noted by reduction in AC activity, shrinking of ED, corneal scarring.
Reduced corneal sensation suggests neurotrophic keratopathy
Monitor IOP

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35
Q

Differential diagnosis of bacterial keratitis?

A

keratitis due to other microorganisms (fungi, acanthamoeba, stromal herpes simplex keratitis and mycobacteria), marginal keratitis, sterile inflammatory corneal infiltrates associated with contact lens wear,
peripheral ulcerative keratitis and toxic keratitis.

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36
Q

How to investigate bacterial keratitis?

A

Corneal scraping. May not be needed for one without ED/away from visual axis/small infiltrate. Margins/base of lesion are scrpaed. Loose mucous/necrotic tissue should be removed prior to scraping. Do not break the gel surface.

Conjunctival swabs may be worthwhile. Calcium alginate swab best option.

CL cases- send lab for culture

Gram stain

MC&S reports obtained ASAP. Resistance on report doesnt always relate to topical instillation as concentration is high

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37
Q

Name some stains and their corresponding organism growth?

A

Gram- bacteria/ fungi/ microspordia

Giemsa-bacteria/ fungi/ acanthamoeba/ microspordia

Calcofluor white- Acanthamoeba/ fungi/ microspordia

ZN stain for AFB- Mycobacterium, Nocardia

Grocott- Gomori methenamine silver- Fungi, acanthamoeba, microspordia

PAS- Fungi, acanthamoeba

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38
Q

Culture mediums for scrapes and their corresponding organism growth?

A

Blood agar- most bacteria except Neisseria, Haemophilus Moraxella

Chocolate agar- Fastidious bacteria. H. influenza, neisseria, Moraxella

Sabouraud dextrose agar- Fungi

Non nutrient agar with E-coli- Acanthamoeba

Brain- heart infusion- Streptococci and Meningococci

Cooked meat broth- Anaerobic (P.acnes) and fastidious bacteria

Lowenstein Jensen- mycobacteria, nocardia

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39
Q

How is bacterial keratitis treated?

A

Hospital admission for patients with aggressive disease/poor compliance
Discontinue CL wear
Plastic eyeshield worn between drop instillation if corneal thinning

Local therapy.
1) Antibiotic monotherapy- fluoroquinolone usual choice empirically. Ciprofloxacin or Ofloxacin used in areas where resistance to earlier gen fluoroquinolones seen.
Moxifloxacin is better.
2) Antibiotic duotherapy may be preferred in aggressive disease or microscopy suggests streptococci. Needs antibiotic to cover gram +/- organisms.
3) Mydriatics- prevent PS formation and reduce pain
4) Steroids- reduce inflammation, improve comfort, minimize scarring.

Systemic antibiotics
1) Some infections eg. N. meningitidis- IM benzylpenicillin. H influenzae, N- gonorrhoea
2) Severe corneal thinning with threatened/actual perforation needs Cipro and tetracycline
3) Scleral involvement may respond to PO/IV treatment.

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40
Q

What did the SCUT trial show (Steroids for Corneal Ulcers Trial)

A

found no eventual benefit in most
cases, but severe cases (counting fingers vision or large ulcers involving the central 4 mm of the cornea) tended to do better. A positive culture result was an inclusion criterion and steroids were introduced after 48 hours of moxifloxacin.

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41
Q

How to manage apparent treatment failure with bacterial keratitis?

A

If no improvement in 24-48 hours of treatment, review abx regime.
No need to change initial therapy if favourable response seen.
If no improvement after further 48 hours, suspend treatment and rescrape with inoculation on broader media.
If cultures remain negative, perform corneal biopsy for histology and culture
Excisional keratoplasty penetrating or deep lamellar may be considered in cases resistant to medical therapy/incipient/actual perforation

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42
Q

How to manage a corneal perforation secondary to bacterial keratitis?

A

small- BCL
Tissue glue often inadequate for larger ones.
PK/corneal patch may be necessary for larger perforations.

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43
Q

How to manage the rare complication of Endophthalmitis with bacterial keratitis?

A

Rare and no specific protocol exists but treat similarly to post operative endophthalmitis

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44
Q

What are the options for visual rehabilitation with bacterial keratitis?

A

1) Keratoplasty (lamellar) for dense corneal scarring
2) Rigid CL for irregular astigmatism
3) Cataract surgery as cataract forms due to severe uveitis

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45
Q

What kind of organisms are fungi?

A

a group of microorganisms that have rigid walls and a distinct nucleus with multiple chromosomes containing both DNA and RNA.

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46
Q

What 2 main types of fungi cause keratitis?

A

Yeasts (eg Candida)
Filamentous fungi (Fusarium, Aspergillus)

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47
Q

Describe what yeasts look like on microscopy?

A

ovoid unicellular organisms that
reproduce by budding, are responsible for most cases of fungal
keratitis in temperate climates.

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48
Q

Describe what Filamentous fungi look like on microscopy?

A

multicellular organisms that produce tubular projections known as hyphae. They are the most common pathogens in tropical climates, but are not uncommon in cooler regions.
The keratitis frequently follows an aggressive course.

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49
Q

What are some predisposing factors for fungal keratitis?

A

Chronic ocular surface disease
Long term topical steroid use
Contact lens wear
Systemic immunosuppression
Diabetes

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50
Q

Symptoms of candida and filamentous fungi?

A

Gradual onset of pain, grittiness, photophobia, blurred vision and watery or mucopurulent discharge.

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51
Q

What are the clinical features of candida and filamentous fungi?

A

Candida- yellow-white densely suppurative infiltrate is typical

Filamentous keratitis- grey or yellow white stromal infiltrate with indistinct fluffy margins
Progressive infiltration with satelite lesions
Feathery branches/ring shaped infiltrate
Rapid progression with necrosis and thinning
Penetration of intact Descemet may lead to endophthalmitis

ED is not invariable sometimes present
May have anterior uveitis, hypopyon, endothelial plaque,

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52
Q

How to investigate suspected fungal keratitis?

A

*KOH preparations with direct microscopic evaluation
*Gram/Giemsa stain 50% sensitive
PAS/Calcofluor white and Methenamine silver are fungal stains
*Culture- corneal scrapes on *Sabouraud dextrose agar.
*PCR analysis of samples sensitive 90%
*Corneal biopsy if no improvement after 3-4 days and no growth from scrapings after 1 week.
*Anterior chamber tap- for resistant cases with endothelial exudate
*Confocal microscopy

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53
Q

What is the treatment for fungal keratitis?

A

*General- consider admission
*Remove epithelium over lesion enhances penetration of antifungal agents.
*Topical antifungals for 48 hours then reduced as signs permit:
*Candida with amphotericin-B /econazole/natamycin/fluconazole/ clotrimazole/ voriconazole
*Filametous fingi treated with natamycin 5%/econazole.
*Broad spectrum abx considered to prevent/address co-infection
*Cyloplegia
*Subconj fluconazole in severe cases
*Systemic antifungals for severe cases
*Tetracycline
*Superficial keratectomy- to debulk lesion
*Therapeutic keratoplasty (PK/DALK)

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54
Q

What is Microspordia in Microspordial Keratitis?

A

obligate intracellular single-celled parasites previously thought to be protozoa but now reclassified as fungi.
Cause disease in immunocompromised eg AIDS
Most common ocular manifestation is keratoconjunctivitis

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55
Q

Signs of Microspordial Keratitis?

A

Bilateral chronic diffuse PEK
Slow progressive deep stromal keratitis
Biopsy shows spores and intracellular parasites
PCR of scrapings low sensitivity

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56
Q

How is Microspordial Keratitis treated

A

Medical therapy for epithelial disease- fumagillin
HAART for AIDS
Stromal disease- topical fumagilin and oral albendazole.

Monitor for hepatic toxicity

Keratoplasty may be indicated but recurrence is high in graft periphery. Cryotherapy to residual tissue may reduce this risk

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57
Q

What is the most common infectious cause of corneal blindness in developed countries?

A

Herpetic eye disease

As many as 60% of corneal ulcers in developing countries may be due to HSV

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58
Q

What are the properties of HSV?

A

enveloped with a cuboidal capsule and has a linear double-
stranded DNA genome.

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59
Q

How many subtypes of HSV are there?

A

HSV1- infections above waist
HSV2- genital infection
Both reside in almost all neuronal ganglia.

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60
Q

How does primary infection of HSV occur?

A

occurs in childhood and is spread by droplet transmission, or less
frequently by direct inoculation. Due to protection by maternal antibodies, it is uncommon during the first 6 months of life.

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61
Q

What is the stepwise procedure which leads to recurrent HSV infections?

A
  • After primary infection the virus is carried to the sensory ganglion for that dermatome (e.g. trigeminal ganglion) where latent infection is established. Latent virus is incorporated in host DNA and cannot be eradicated with presently available
    treatment.
    *Subclinical reactivation can periodically occur, during which
    HSV is shed and patients are contagious.
    *Clinical reactivation. A variety of stress factors such as fever,
    hormonal change, ultraviolet radiation, trauma, or trigeminal
    injury may cause clinical reactivation, when the virus replicates and is transported in the sensory axons to the periphery.
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62
Q

What is the rate of ocular recurrence of HSV?

A

fter one episode is about 10%
at 1 year and 50% at 10 years. The higher the number of previous attacks the greater the risk of recurrence.

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63
Q

Risk factors for severe disease in HSV infections?

A

atopic eye disease,
childhood,
immunodeficiency or suppression, malnutrition,
measles and malaria.

Inappropriate use of topical steroids may enhance the development of
geographic ulceration

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64
Q

What are the signs and symptoms of HSK infection?

A

Symptoms- mild-mod discomfort/ blurry vision/ photophobia

Signs- reduced VA, central desquamation causing linear branching ulcer mostly centrally with terminal bulbs, Reduced corneal sensation, steroids worsen this, mild subepithelial haze, mild AC activity, follicular conjunctivitis, vesicular eyelid lesions, elevated IOP

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65
Q

How to investigate suspected HSV epithelial keratitis?

A

Ix unnecessary as clinical diagnosis.
Pre treatment scrapes can be sent.
PCR/immunohistochemistry
Giemsa stain

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66
Q

What are the differentials for HSK?

A

*HZK
*Healing abrasion
*Acanthamoeba keratitis
*Epithelial rejection in corneal graft
*Tyrosinaemia type 2
*Dendritiform keratopathy caused by polyquadernium-1 a preservative in *CL solution and tear replacement products

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67
Q

What is the treatment for HSK?

A

*Topical- Aciclovir 3% or Ganciclovir 0.15% gel 5x/day. Trifluridine but needs 9x/day.
*Debridement- for resistant cases. Wipe corneal surface with cotton bud remove epithelium 2mm beyond edge of ulcer.
*Signs of tx toxicity- SPEE, follicular conjunctivitis, epithelial whorling means poor/non compliance
*PO antivirals eg aciclovir 5x/day for 5-10 days for immunodeficient patients.
*Cycloplegia
*Skin lesions treated with Aciclovir cream
*Interferon monotherapy
*IOP control- avoid prostaglandins
*Topical steroids not used unless disciform keratitis can cause perforation

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68
Q

What is the aetiology of Disciform keratitis?

A

The aetiology of disciform keratitis (endotheliitis) is unclear.
It may be the result of active HSV infection of keratocytes or
endothelium, or a hypersensitivity reaction to viral antigen in the
cornea.

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69
Q

What are the symptoms and signs of Disciform keratitis?

A

Symptoms- gradual blurry vision. A clear past history of epithelial ulceration not always clear.

Signs- central stromal oedema with overlying epithelial oedema. Large KP’s under oedema, folds in descement membrane in severe cases. Wessly immune ring of deep stromal haze signifies deposition of viral antigen and host antibody complexes. IOP may be elevated. Reduced corneal sensation. Mid - stromal scarring causes interstital keratitis.

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70
Q

What is the treatment for disciform keratitis?

A
  • Initial treatment is with topical steroids (prednisolone 1% or
    dexamethasone 0.1%) with antiviral cover, both four times daily. Monitor IOP.
  • Subsequent prednisolone 0.5% OD is safe to stop antiviral cover.
  • Oral steroids are sometimes used.
  • Topical ciclosporin may be useful in epithelial ulceration and to facilitate tapering of topical steroids eg steroid related IOP elevation.
  • Fine needle diathermy and laser techniques reported to successfully address established corneal neovascularization
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71
Q

What is Necrotizing stromal keratitis?

A

Rare condition thought to result from active viral replication within the stroma with immune mediated inflammation. May be difficult to differentiate from severe disciform keratitis.

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72
Q

Signs of necrotizing stromal keratitis?

A

*Stromal necrosis and melting with profound interstitial opacification
*Anterior uveitis with KP’s
*ED may be present
*Progression to scarring/ vascularization and lipid deposition common

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73
Q

Treatment for necrotizing stromal keratitis?

A

Similar to disciform keratitis but oral antiviral supplementation initially at upper end of dose range commenced. Restoration of ED is critical

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74
Q

What is Neurotrophic keratopathy?

A

Caused by failure of re-repithelialization due to corneal anaesthesia

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75
Q

Signs of Neurotrophic keratopathy?

A

*Non healing ED
*Stroma beneath defect is grey/opaque and may thin
*Secondary bacterial and fungal infection may occur

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76
Q

Treatment for Neurotrophic keratopathy

A

*Treatment same as persistent ED. *Topical steroids to control any inflammation should be kept to a minimum

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77
Q

What is herpetic iridocyclitis and how is it treated?

A

*Occurs without signs of active corneal inflammation.
*May be associated with direct viral activity.
*IOP elevation common presumed due to trabeculitis.
*Steroid induced IOP elevation may be relatively common in herpetic irits.
*Treatment with topical steroids but adjunctive PO aciclovir may be given

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78
Q

What are the statistics and indications for prophylactic PO aciclovir use?

A

*reduces the rate of recurrence of
epithelial and stromal keratitis by about 50%

*Prophylaxis in patients with frequent debilitating recurrences, particularly if bilateral or involving an only eye. The standard daily dose of aciclovir
is 400 mg twice daily, but if necessary a higher dose can be tried, based on practice in the management of systemic herpes simplex infection. Continual use for many years has been documented for systemic indications. The prophylactic effect
decreases or disappears when the drug is stopped. Excretion is
via the kidney, so renal function should be checked periodically during long-term treatment.

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79
Q

Complications of herpetic eye disease?

A

1) Secondary bacterial infection
2) Glaucoma secondary to inflammation/chronic steroid use
3) Cataract due to prolonged steroid use/inflammation
4) Iris atrophy secondary to kerato-uveitis

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80
Q

What are the threats to keratoplasty?

A

Recurrence of herpetic eye disease and rejection are common and threaten the survival of corneal grafts.

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81
Q

What medication can help reduce the risk of graft rejection and herpetic disease recurrence?

A

*Topical antivirals given during a rejection episode may reduce epithelial viral reactivation but toxicity may delay re-epithelialization

*Prophylactic PO aciclovir (400mg) BD improves graft survival and given to patients undergoing PK for herpetic eye disease

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82
Q

What is the incidence of herpes zoster ophthalmicus?

A

Estimated that one in three people will develop the condition in their lifetime. Most patients are not immunocompromised.

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83
Q

What is the pathogenesis for HZO?

A

*Shingles involving the dermatome supplied by the ophthalmic division of the trigeminal nerve
*Ocular involvement is rarely clinically significant when disease affects maxillary division alone.
*VZV causes both chickenpox and shingles

*Primary infection with chickenpox–>virus travels retrograde manner to dorsal root and cranial nerve sensory ganglia–> remains dormant for decades–> reactivation after VZV specific cell mediated immunity fades.

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84
Q

What are the mechanisms of ocular involvement in HZO?

A

*Direct viral invasion via conjunctivitis and epithelial keratitis
*Secondary inflammation with occlusive vasculitis may cause episcleritis/scleritis, keratitis, uveitis optic neuritis, CN palsies.
*Reactivation causes necrosis and inflammation in affected sensory ganglia causing corneal anaesthesia causing neurotrophic keratopathy

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85
Q

What are the indicators that HZO may cause ocular involvement?

A

*Hutchinson sign- vesicles in the skin supplied by external nasal nerve, a branch of nasociliary nerve. Correlates to ocular involvement but not to severity

*Age- sixth and seventh decades. More severe signs in elderly

*AIDS patients have severe disease and be early indication of HIV infection.

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86
Q

What are the general features of Acute shingles?

A

Prodromal phase- 3-5 days with tiredness/fever/malaise. Superficial itch, tingling, burning.
Skin lesions- painful erythematous areas with maculopapular rash. Rash respects midline. Vesicles appear within 24 hours becoming confluent over 2-4 days. Vesicles pass through a pustular phase before crusting after 2-3 weeks. Large deep haemorrhagic lesions common in immunodeficient patients. Lesions heal to leave residual scars

Disseminated Zoster involving multiple dermatomes may indicate immunodeficiency or malignancy

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87
Q

How to investigate suspected acute shingles?

A

If uncertain, vesicular fluid for PCR or immunomicroscopy. PCR for plasma VZV DNA positive in 40%. IgM antibodies may be found in minority of early stages.

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88
Q

What is the treatment for acute shingles?

A

PO antivirals- given within 72 hours of rash onset reducing risk of post herpetic neuralgia. Aciclovir 800mg 5x/day for 7-10 days. Should NOT be used in combination with 5-FU

IV aciclovir TDS for severe disease and mod-severe immunosuppression

Systemic steroids with PO pred- controversial. Dont give immunocompromised. Thought to reduce acute pain and accelarated skin healing

ID opinion for immunocompromised patients

Symptomatic treatment for skin- drying cold compress.

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89
Q

How can acute shingles be prevented?

A

Vaccination- Zoster vaccine live (effect lost within 10 years)
Recombinant zoster vaccine- requires at least 2 vaccines has 10% incidence of local/acute systemic reaction

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90
Q

HZO related acute eye disease?

A

*Acute epithelial keratitis- in over 50% patients, resolves spontaneously over few days.Dendritic lesions with tapered ends rather than bulbs
*Conjunctivitis- with lid margin vesicles. Treatment not required in absence of corneal disease
*Episcleritis- spontaneously resolves. Mild NSAID may help
*Scleritis- Oral fluribropfen TDS. PO steroids with antivirals in severe cases
*Nummular keratitis-at the site of epithelial lesions 10 days after rash
*Stromal (interstitial) keratitis- 5% 3 weeks after onset of rash with scarring. Responds to topical steroids
*Disciform keratitis- less common than with HSV leading to corneal decompensation. Treat with steroids
*Anterior uveitis- sectoral iris ischaemia and atrophy
*Posterior uveitis- PORN and ARN.
*Monitor IOP- avoid prostaglandin analogues

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91
Q

HZO related chronic eye disease?

A

*Neutotrophic keratopathy-in 50% but mild and settles over few months.
*Scleritis- chronic leading to patchy scleral atrophy.
*Mucous plaque keratitis in 5%
*Lipid degeneration with severe nummular/disciform keratitis
*Subconjunctival scarring
*Eyelid scarring with ptosis/cicatricial entropion, trichasis, lid notching, madarosis

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92
Q

What is post herpetic neuralgia?

A

Pain persistent for more than 1 month after rash has healed
Improves overtime- 2% affected after 5 years.
Impairs QoL lead to depression with danger of suicide. Pain clinic referral indicated.

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93
Q

How can post herpetic neuralgia be managed (local and systemic)?

A

Local
*Cold compress
*Topical capsaicin or lidocaine patches

Systemic
*Analgesia- paracetamol
*Codeine
*TCA- amitryptilline
*Carbamazepine
*Gabapentin, sustained release Oxycodone or both

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94
Q

What is interstitial keratitis and what is its presumed pathogenesis?

A

inflammation of the corneal stroma
without primary involvement of the epithelium or endothelium.
The inflammation is thought to be an immune-mediated process triggered by an appropriate antigen

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95
Q

What pathogens can cause interstitial keratitis?

A

HSV, VZV, TB, Lyme, Parasitic disease, Sarcoidosis, Cogan syndrome, Non infectious inflammatory conditions

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96
Q

When does syphillitic interstitial keratitis tend to happen?

A

Congenital infection, though acquired infection can happen.

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97
Q

What are some early and late systemic features of syphilitic interstitial keratitis?

A

Early- failure to thrive, maculopapular rash, mucosal ulcers, rhagades, organ involvement

Late- sensorineural deafness, saddle shaped nasal deformity, sabre tibiae, bulldog jaw, Hutchinson teeth, Clutton joints

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97
Q

What are some ocular features of syphilitic interstitial keratitis?

A

Anterior uveitis
Dislocated/subluxated lens
cataract
optic atrophy
salt and pepper retinopathy
Argyll Robertson pupils

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98
Q

How is syphilitic keratitis treated?

A

Topical steroids
cycloplegics
Systemic therapy under GUM/ID

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98
Q

What are some symptoms and signs of syphilitic interstitial keratitis?

A

Symptoms- presentation of congenital infection between 5-25 years. Initially severe anterior uveitis with blurring. Bilateral in 80%. Acquired is unilateral commonly.

Signs- profoundly decreased VA, Limbitis with deep stromal vascularization, granulomatous anterior uveitis, cornea clears with ghost vessels overtime, if cornea inflamed, can bleed into stroma. Healed stage ghost vessels, feathery deep stromal scarring, mild astigmatism, band keratopathy

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99
Q

What is Cogan syndrome?

A

Rare autoimmune systemic vasculitis with ocular inflammation/vestibuloauditory dysfunction developing within months of each other.
Acute phase may last months- years
Susac syndrome should be considered in the differential diagnosis

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100
Q

What are some clinical features of Cogan syndrome?

A

Vestibuloauditory - deafness, tinnitus, vertigo
Ocular- Redness, pain, photophobia, blurry vision. Corneal involvement first with bilateral peripheral anterior stromal opacities. Deeper opacities and corneal neovascularization then ensue with central progression. Uveitis, scleritis and retinal vasculitis may develop

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101
Q

What are the investigations for suspected Cogan syndrome?

A

ESR
CRP
Antibodies to ear antigen
MRI may show other inner ear abnormalities

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102
Q

What is the treatment for Cogan syndrome?

A

Topical steroids for keratitis, with addition measures as appropriate

Systemic steroids- Vestibuloauditory symptoms need immediate IV prednisolone to prevent hearing loss. Immunosuppressive therapy may be required. Sytemic steroids for scleritis/retinal vasculitis

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103
Q

What kind of pathogen is Acanthamoeba?

A

Ubiquitous free living protozoa commonly found in soil, fresh, brackish water and upper respiratory tract

104
Q

What is the active form of Acanthamoeba?

A

Cystic form is highly resilient and under appropriate environmental conditions cysts turn into trophozoites with tissue penetration and destruction

105
Q

What are the signs and symptoms of Acanthamoeba keratitis?

A

Often misdiagnosed as herpetic keratitis
Symptoms- blurry vision/discomfort. Pain severe and disproportionate to findings

Signs- epithelial surface irregular and greyish in early disease. Epithelial pseudodendrites resembling herpetic lesions form, limbitis with diffuse or focal anterior stromal infiltrates, perineural infiltrates seen in first few weeks and pathognomonic. Gradual enlargement of infiltrates to form ring abscess. Scleritis may develop which is reactive. Slow progressive stromal opacification and vascularization. Corneal melting may occur at any stage when stromal disease present.

106
Q

What are the investigations for suspected Acanthamoeba keratitis?

A

If limited response to microbial therapy, consider AK!

Staining of scrapings using PAS/ calcofluour white. Gram and Giemsa stain can also show cysts
Culture- non nutrient agar seeded with dead E-coli which trophoziotes consume
Immunohistochemistry, PCR, in vivo confocal microscopy. Corneal biopsy may be needed

107
Q

How is Acanthamoeba keratitis treated?

A

Debridement of involved epithelium is believed to help drop penetration
Topical amoebicides. Acanthamoeba cysts resistant to most antimicrobials.
1) PHMB 0.02% and chlorhexidine 0.02%. kill trophozoites and cysticidal
2) Hexamidine or propamidine (Brolene).
3) Voriconazole and other azole antifungals may be effective

A clear response may take 2 weeks

Avoid steroid use but low dose therapy delayed for at least 2 weeks until starting treatment with amoebicides for persistent inflammation.

Pain control- NSAIDS
Therapeutic keratoplasty for resistant cases eg perforation. Late scarring PK

108
Q

What is marginal keratitis and its pathogenesis?

A

caused by hypersensitivity reaction to staphylococcal exotoxins and cell wall proteins with deposition of antigen- antibody complexes in peripheral cornea with secondary lymphocytic infiltration.
Lesions culture negative but S. aureus isolated from lid margins

109
Q

What are the symptoms and signs of marginal keratitis?

A

Symptoms- mild discomfort, redness, lacrimation. Inflammation may be in both eyes

Signs- chronic blepharitis, inferior PEE’s early sign, subepithelial marginal infiltrates separated from limbus by clear zone with adjacent conj hyperaemia.
Any ED smaller than infiltrate.
Coalescense and circumferential spread
Little or no AC reaction even with large infiltrates
With no treatment may resolve in 1-4 weeks depending on severity. Occasional scarring and thinning with mild pannus

110
Q

What is the treatment for marginal keratitis?

A

Weak steroid eg FML or Pred 0.5% QDS for 1-2 weeks sometimes combined with topical abx. Oral tetracycline course for recurrent disease.

111
Q

What is Phlyctenulosis?

A

A self limiting disease but can be severe.
Mostly occurs as a result of presumed delayed hypersensitivity reaction to staphylococcal antigen, can be associated with Rosacea.

In developing countries associated with TB/Helminth infestiations

112
Q

What are the symptoms and signs of Phlyctenulosis?

A

Symptoms- photophobia, lacrimation, blepharospasm

Signs- small white limbal or conj nodule with intense local hyperaemia, limbal phlycten may extend onto cornea. Spontaneous resolution in 2-3 weeks. Healed lesion leaves triangular limbal based scar with superficial vascularization and thinning.
Very large necrotizing or miliary lesions may occur

113
Q

What are the investigations for suspected Phlyctenulosis?

A

Consider TB ix in endemic areas/risk factors present

114
Q

What is the treatment for Phlyctenulosis?

A

A short course of topical steroid accelerates healing and is often
given with a topical antibiotic. Recurrent troublesome disease may
require an oral tetracycline and it is important to treat associated
blepharitis.

115
Q

What is Rosacea and what is its aetiology?

A

chronic idiopathic dermatosis
involving the sun-exposed skin of the face and upper neck. Ocular
complications develop in 6–18% of patients.

may involve vascular factors, together with an abnormal response to commensal skin bacteria and Demodex follicular mites. Exacerbation by H. pylori infection has been suspected.

116
Q

What are the signs and symptoms of Rosacea?

A

Non specific irritation and lacrimation
Lid signs- margin telangiectasia, posterior blepharitis associated with recurrent meibomian cyst formation
Conj hyperaemia especially bulbar. Rarely cicatricial conjunctivitis, conj granulomas and phlyctenulosis may occur.

Cornea- inferior PEE, peripheral vascularization, marginal keratitis, focal/diffuse corneal thinning, perforation, corneal scarring + vascularization

117
Q

What is the treatment for Rosacea?

A

Topical- lubricants, hot compress lid hygiene, topical abx (fusidic acid, erythromycin, azithromycin) to lid margins at bedtime 4/52. Steroids for exacerbations- lowest prep to minimize thinning.

Systemic- tetracyclines alter meibomian gland function to lower fatty acid production and direct antiinflammatory effect. Severe disease may require immunosuppression, retinoids can help but worsen features.

118
Q

What are some causes of peripheral ulcerative keratitis (PUK)?

A

Marginal keratitis
Mooren ulcer
Terrien marginal degeneration
Dellen
Systemic autoimmune disease
Ocular rosacea, furrow degeneration, pellucid marginal degeneration

119
Q

What is a Mooren ulcer and how many forms are there?

A

Rare autoimmune disease with progressive circumferential peripheral stromal ulceration with later central spread.

2 forms. First affects older patients, often in one eye and responds to medical therapy.
Second form more aggressive needing immunosuppression with poor prognosis. May be bilateral with severe pain, younger patients

120
Q

What are the signs and symptoms of Mooren ulcer?

A

Symptoms: pain is prominent, may be severe. Photophobia, blurred vision

Signs: peripheral ulceration involving superficial 1/3rd of stroma with epithelial loss. An undertermined and infiltrated leading edge is characteristic. Limbitis without scleritis may be present which distinguishes from systemic disease associated PUK. Progressive circumferential and central stromal thinning. Vascularization with the bed of the ulcer upto leading edge but not beyond.

Healing stage: thinning/ vascularization, scarring

121
Q

Complications of Mooren ulcer?

A

severe astigmatism
perforation following minor trauma
secondary bacterial infection
cataracts
glaucoma

122
Q

How to treat Mooren ulcer?

A

*Top steroids: hourly with low frequency prophylactic antibiotic. If effective, taper tx over months
*Top ciclosporin may be effective but takes weeks to have effect
*Tacrolimus 0.1% ointment for refractory cases
*Artificial tears/NAC
*Excision of necrotic conjunctival tissue
*Systemic immunosuppression
*Systemic collagenase inhibitors eg doxycycline
*Lamellar keratectomy with dissection of residual central island in advanced disease
*Perforation management
*Visual rehab with keratoplasty once inflammation settled.

123
Q

What is the mechanism of PUK associated with systemic autoimmune disease?

A

PUK may precede or follow onset of systemic features.
Severe peripheral corneal infiltration, ulceration or thinning unexplained by evident ocular surface disease prompt Ix for systemic collagen vascular disease.

Immune complex deposition in peripheral cornea, episcleral and conjunctival capillary occlusion with secondary cytokine release and inflammatory cell recruitment, upregulation of collagenases and reduced activity of inhibitors.

124
Q

What systemic conditions is PUK associated with?

A

RA- Bilateral in 30% cases
Granulomatosis with polyangiitis (Wegner Granulomatosis)- 2nd most common systemic association. Ocular complications are the initial presentation in 50%
Others eg Polyarteritis nodosa, relapsing polychondriti, SLE, Crohns disease

125
Q

What are some clinical features associated with PUK?

A

Crescenteric ulceration with ED, thinning, stromal infiltrate at limbus. Spreading circumferentially and occasionally central. Extension into sclera may occur in contrast to Mooren

Limbitis, episcleritis, scleritis. As with Mooren ulcer no separation between ulcerative process and limbus

Advanced disease may lead to CL cornea/perforation

Rheumatoid paracentral ulcerative keratitis (PCUK)- distinct entity with punched out more central lesion with little infiltrate in quiet eye. Rapid perforation may occur with good response to topical ciclosporin, BCL and glue application.

126
Q

What is the treatment for systemic disease associated PUK?

A

*Topical steroids- pulsed IV steroids for acute disease and immunosuppressive/ biologics for long term management
*Lubricants
*Antibiotics prophylaxis if ED present
*PO tetracycline for anticollagenase effect
*Topical steroids worsen thinning so avoided. Relapsing polychondritis may be an exception

127
Q

What is Terrien marginal degeneration?

A

Uncommon idiopathic thinning of peripheral cornea in young adult- elderly patients.
Some associated with episcleritis/scleritis. 75% hare male and usually bilateral but asymmetrical

128
Q

What are the symptoms and signs of Terrien Marginal Degeneration?

A

Symptoms- commonly asymptomatic but gradual visual decline due to astigmatism. Few have episodic pain and inflammation.

Signs- fine yellow-white refractile stromal opacities, frequently with mild superficial vascularization starting superiorly separated from limbus by clear zone. There is no ED and may resemble arcus senilis.
Slow progressive circumferential thinning leads to peripheral gutter, outer slope of which shelves gradually with rise in central part. Band of lipid commonly seen around central edge.

129
Q

What is the treatment for Terrien Marginal Degeneration:

A

Safety spectacles if thinning ++
CL for astigmatism. Scleral/ soft lenses with rigid gas permeable
Surgery- crescenteric or annular excision of gutter with lamellar/ full thickness transplant.

130
Q

What is neurotrophic keratopathy and what is its pathogenesis?

A

loss of trigeminal innervation to cornea leading to partial/ complete anaesthesia. With loss of protective sensory stimulus, this leads to intracellular oedema/ exfoliation/ loss of goblet cells and epithelial breakdown with persistent ulcers.

131
Q

What are the causes of neurotrophic keratopathy?

A

*Trigeminal ganglion surgical ablation for neuralgia
*Stroke
*Tumour
*Peripheral neuropathy eg diabetes
*Ocular disease eg HSV, HZK

132
Q

What are the signs/symptoms of neurotrophic keratopathy?

A

Full CN exam mandatory.
Signs- reduced corneal sensation.
Stage 1: interpalpebral epithelial irregularity and stain with mild opacification, oedema and tiny focal defects
Stage 2: Large persistent ED with rolled and thickened edges and puched out configuration with underlying stromal oedema.
Stage 3: Stromal melting with secondary infection

Perforation uncommon but can happen quick with sec infection

133
Q

How to treat neurotrophic keratopathy?

A

*Discontinue toxic medication
*Lubricants
*Anticollagenase agents (NAC/tetracyclines)
*Cenergemin- topical recombinant human nerve growth factor beneficial in moderate or severe neurotrophic ulcer in adults.
*Protection of ocular surface- lid taping, botox induced ptosis, *Tarsorrhaphy
*Therapeutic silicone CL
*Amniotic membrane patching with temporary central tarsorrhaphy
*Perforation management as previously discussed
*Corneal neurotization from supratrochlear nerve using sural graft

134
Q

What is exposure keratopathy?

A

A result of incomplete lid closure (lagophthalmos) with corneal drying despite normal tear production.
Caused by neuroparalytic (Facial nerve palsy), reduced muscle tone in parkinsonism, mechanical lid scarring, eczematous skin tightening, post blepharoplasty and proptosis

135
Q

What are the symptoms and signs of exposure keratopathy?

A

Symptoms- those of dry eye
Signs- Mild PEE’s inferior 1/3rd of cornea due to lagophthalmos
Epithelial breakdown
stromal melting
inferior fibrovascular changes leading to Salzmann degeneration
Secondary infection

136
Q

What is the treatment of exposure keratopathy?

A

Reversible exposure:
*Artificial tears during day and ointment at night
*Lid taping at night
*Bandage silicone hydrogel/ scleral contact lens
*Manage proptosis by orbital decompression
*Temporary tarsorrhaphy

Permanent exposure:
*Permanent tarsorrhaphy
*Gold weight upper lid insertion for 7th nerve palsy
*Permanent central tarsorrhaphy, amniotic membrane graft/ conj flap when poor vision

137
Q

What is infectious crystalline keratopathy and which pathogen causes it?

A

Rare indolent infection in patients on long term topical steroid therapy with ED following penetrating keratoplasty.

Strep viridans commonly isolated but can be other bacteria/fungi.

138
Q

What are the signs/symptoms of infectious crystalline keratopathy?

A

Slow progressive grey white branching stromal opacities with minimal inflammation usually intact overlying epithelium.
Biofilm allows survival of microorganism, reducing antibiotic bioavailability.

139
Q

How is infectious crystalline keratopathy treated?

A

Culture/biopsy performed to determine the organism and topical antibiotics for several weeks.
Adjunctive therapies are distuption of microorganism biofilm by laser, intrastromal antibiotics and keratectomy.
With corneal scarring, corneal transplant required

140
Q

What is Thygeson superficial punctate keratitis?

A

an uncommon idiopathic, usually bilateral, condition characterized by exacerbations and remissions. It is commonly of onset in young adulthood but can affect patients of any age and may recur over decades.

141
Q

What are the signs and symptoms of Thygeson superficial punctate keratitis?

A

Symptoms- recurrent attacks of irritation, photophobia, blurry vision and watering

Signs- granular, coarse, slightly elevated greyish epithelial lesions staining with fluorescein involving central cornea. Mild subepithelial haze may be present if topical antivirals have been used. Little to no conj hyperaemia.

142
Q

What is the treatment for Thygeson superficial punctate keratitis?

A

*Topical
Lubricants
Steroids- Low potency prep BD with tapering to OW.
Ciclosporin- if response to steroids inadequate
Antivirals- not helpful

*Contact lenses
*Phototherapeutic keratectomy short term relief, recurrence is likely.

143
Q

What is filamentary keratopathy?

A

a common condition that can cause
considerable discomfort. It is thought that a loose area of epithelium acts as a focus for deposition of mucus and cellular debris.

144
Q

What are the causes of filamentary keratopathy?

A

*Aqueous deficiency (keratoconjunctivitis sicca)
*Excessive contact lens wear
*Corneal epithelial instability (recurrent erosion syndrome,
corneal graft, cataract surgery, refractive surgery and drug toxicity)
*Superior limbic keratoconjunctivitis
*Bullous keratopathy
*Neurotrophic keratopathy
*Prolonged or frequent eye closure

145
Q

What are the signs and symptoms of filamentary keratopathy?

A

Symptoms- discomfort with FB sensation, redness and photophobia

Signs- strands of degenerated epithelial cells and mucus moving with blinking attached to cornea at one end. Filaments stain with Rose Bengal Small ED at base of filaments may be seen. Chronic filaments form plaques.

146
Q

What is the treatment for filamentary keratopathy?

A

*Treat underlying causes
*Topical medication changed if suspecting toxic effects. Remove preservatives
*Mechanical removal of filaments
*Mucolytics- NAC drops
*NSAIDS- eg diclofenac
*Hypertonic saline 5% QDS encourage adhesion of loose epithelium
*BCL protect cornea from shearing lid action

147
Q

What is RCES and how is it caused?

A

Recurrent corneal epithelial erosion is caused by an abnormally weak attachment between the basal cells of the corneal epithelium and their basement membrane.

Minor trauma, such as eyelid–cornea interaction during sleep, can be sufficient to precipitate detachment. Erosions may be associated with previous trauma or rarely corneal surgery and with some corneal dystrophies.

148
Q

What are the signs and symptoms of RCES?

A

Symptoms- severe pain, photophobia, redness, blepharospasm, watering wake the patient at night or in the morning. Usually a history of prior corneal abrasion

Signs- ED may not be present on exam as healing rapid but extent of loose epithelium present and reduced BUT. Infiltrate no present though greyish sloughed epithelium may be seen. No sign of abnormality once defect healed but epithelial BM disturbance eg microcysts/punctate/linear fingerprint opacities seen. Typically bilateral in stromal dystrophy.

149
Q

What is the treatment for RCES?

A

Acute
*Abx ointment QDS, Cyclo TDS
*BCL severe cases. Use abx drops rather than ointment
*Debridement of epithelium with sterile cellulose sponge/cotton tipped applicator improve comfort allow healing
*Topical diclofenac
*Topical anaesthetic reduce pain
*Hypertonic saline 5% improve epithelial adhesion
*After resolution prophylaxis lubricants

Recurrent symptoms
*Topcial lubricants gel/ ointment
*PO Doxy and to steroid to inhibit MMP’s
*Long term BCL
*Simple debridement of epithelium in involved areas with smoothing of bowman layer with diamond burr/excimer laser.
*Anterior stromal puncture for off axis areas.

150
Q

What is Xerophthalmia?

A

Vit A essential for maintaining body epithelial surfaces, immune function and synthesis of photoreceptor proteins.

Xerophthalmia refers to the spectrum ofocular disease caused by inadequate vitamin A intake and is a late manifestation of severe deficiency.

151
Q

What is the WHO grading for Xerophthalmia?

A

XN = night blindness
X1 = conjunctival xerosis (X1A) with Bitot spots (X1B)
X2 = corneal xerosis
X3 = corneal ulceration, less than one-third (X3A); more than one-third (X3B)
XS = corneal scar
XF = xerophthalmic fundus

152
Q

What are the clinical features of Xerophthalmia?

A

Symptoms- night blindness, discomfort and loss of vision

Conj- Dry conj interpalpebral zone loss of goblet cells, squamous metaplasia and keratinization
Bitot spots triangular patches of foamy keratinized epithelium.

Cornea- lustreless appearance due to secondary xerosis
Bilateral PEE’s interpalpebral zone progress to ED but reversible
Keratinization
Sterile corneal melting leading and liquiefactive necrosis (keratomalacia) leading to perforation

Retinopathy- yellowish peripheral dots and decreased electroretinogram amplitude

153
Q

What is the treatment for Xerophthalmia?

A

Keratomalacia is an indicator of very severe vitamin A deficiency
and should be treated as a medical emergency due to the risk of
death, particularly in infants.

*Systemic treatment- PO (oil-based 200 000 IU) or IM (aqueous-based 100 000 IU) vitamin A for keratomalacia. Multivitamin supplements and dietary sources of vitamin A are also administered.
*Local treatment consists of intense lubrication, topical retinoic acid and management of perforation.

154
Q

What are some common causes of corneal ectasia?

A

Keratoconus
Keratoglobus
Pellucid marginal degeneration

155
Q

What is keratoconus?

A

a progressive disorder in which central or paracentral corneal stromal thinning occurs, accompanied by
apical protrusion and irregular astigmatism. Approximately 50%
of normal fellow eyes will progress to KC within 16 years.

156
Q

How is keratoconus graded?

A

It can be graded by the highest axis of corneal power on keratometry as
mild (<48 D),
moderate (48–54 D)
severe (>54 D).

157
Q

At what ages does keratoconus present?

A

commonly during the teens or twenties, with features initially in only one eye.

158
Q

What are some systemic associations of keratoconus?

A

Down syndrome
Ehlers–Danlos
Marfan syndromes
osteogenesis imperfecta.

Ocular associations include vernal
keratoconjunctivitis, blue sclera, aniridia, Leber congenital amaurosis, retinitis pigmentosa, as well as persistent eye rubbing from
any cause.

159
Q

What are the signs and symptoms of keratoconus?

A

Symptoms- unilateral vision impairment due to progressive myopia and astigmatism. Occasionally present with hydrops

Signs- DO from a distance shows oil droplet reflex. Retinoscopy shows irregular scissoring reflex, slit lamp biomicroscopy fine vertical deep stromal stress lines (Vogt striae), disappearing with pressure on globe, epithelial iron deposits with cobalt blue filter surrounding base of the cone (Fleischer ring). Progressive corneal protrusion in cone configuration with thinning maximal at apex, bulging of lower lid in downgaze (Munson sign). Acute hydrops caused by a rupture in stretched descemet membrane allowing aqueous into cornea with pain/photophobia, decreased vision.
The break heals within 6-10 weeks oedema clears, stromal scarring develops

160
Q

How to treat acute hydrops from keratoconus?

A

treated with cycloplegia, hypertonic (5%) saline ointment and patching or a soft bandage contact lens. Accelerated resolution has been reported with intracameral gas injection in the acute stage.

161
Q

What is the treatment for keratoconus?

A

*Avoid eye rubbing
*Spectacles/ soft CL
*Rigid contact lenses sometimes scleral for higher degrees of astigmatism.
*Collagen cross linking with riboflavin drops to photosensitize the eye after UVA exposure. Can be combined with ring segment insertion. CXL used after documented progression
*Intracorneal ring segment implantation- laser/mechanical channel creation safe
*Keratoplasty- PK or DALK in severe disease. History of hydrops contraindication to DALK due to descemet membrane discontinuity
*LASIK Contraindicated

162
Q

What is pellucid marginal degeneration and when does it typically present?

A

Pellucid marginal degeneration is a rare progressive peripheral
corneal thinning disorder, typically involving the inferior cornea
in both eyes. Presentation is usually in adulthood.

163
Q

What are the symptoms and signs of pellucid marginal degeneration?

A

Symptoms- slow progressive blurring due to astigmatism
Signs- bilateral slow progressive crescenteric 1-2mm band of inferior corneal thinning extending from 4 to 8 o clock 1mm from the limbus
Epithelium is intact cornea above thinned area shows ectasia and flattened
Corneal topography- butterfly pattern with severe astigmatism and diffuse steepening of inferior cornea

164
Q

Difference in clinical signs between pellucid marginal degeneration, keratoglobus and keratoconus?

A

In pellucid marginal degeneration, Fleischer rings and Vogt striae do not occur and acute hydrops is rare.

In keratoglobus compared to keratoconus, the cornea
develops globular rather than conical ectasia and is associated with
generalized corneal thinning

165
Q

How is pellucid marginal degeneration treated?

A

Early cases- specs and CL
Surgical- large eccentric PK, thermocauterization, crescenteric lamellar keratoplasty, wedge resection of diseased tissue, epikeratoplasty, intracorneal ring segment implanation. Collagen cross linking results are encouraging

166
Q

What is keratoglobus and what are its differentials?

A

extremely rare condition that can be present at birth when differential diagnosis is from congenital glaucoma
and megalocornea and associations may be present, or acquired, with onset in adulthood

167
Q

What does corneal topography of keratoglobus show?

A

Generalised steepening

168
Q

Treatment for keratoglobus?

A

Surgery is difficult and contact lens wear is often unsatisfactory. Intrastromal ring segments and cross-linking may have utility. Special care
should be taken to protect the eyes from trauma.

169
Q

What are some important corneal epithelial dystrophies?

A

Cogan (epithelial basement membrane) dystrophy
Meesmann epithelial dystrophy

Other epithelial and subepithelial dystrophies are Lisch epithelial corneal dystrophy, subepithelial mucinous corneal dystrophy, gelatinous drop like corneal dystrophy

170
Q

What is Cogan dystrophy and what are its associations?

A

Most patients no family history. Corneal changes considered secondary to degeneration/ trauma

The occurrence of bilateral recurrent erosions with no history of trauma suggests basement membrane dystrophy.

171
Q

What is the inheritance pattern for Cogan dystrophy?

A

Sporadic condition secondary to degeneration
AD inheritance

172
Q

What does histology show for Cogan dystrophy?

A

thickening of the basement membrane with deposition of fibrillary protein between the basement membrane and the Bowman layer. Basal epithelial cell hemidesmosomes are deficient

173
Q

What is the onset and what signs are seen in Cogan dystrophy?

A

Second decade. 10% develop RCES in 3rd decade, remainder asymptomatic throughout life.

Signs- lesions best seen via retroillumination/ scleral scatter.
Dot like and microcystic epithelial lesions
Subepithelial map like patterns surrounded by faint haze
Whorled fingerprint like lines
Bleb like subepithelial pebbled glass pattern

174
Q

How is Cogan dystrophy treated?

A

Same as RCES

175
Q

What is Meesmann epithelial dystrophy and what is the inheritance pattern?

A

a rare non-progressive abnormality
of corneal epithelial metabolism, underlying which mutations in the genes encoding corneal epithelial keratins have been reported.

AD inheritance

176
Q

What does histology of Meesmann dystrophy?

A

irregular thickening of the epithelial basement membrane and intraepithelial cysts

177
Q

What are the signs and symptoms of Meesmann dystrophy?

A

Symptoms- may be asymptomatic, mild RCES and blurring.

Signs- Myriad tiny intraepithelial cysts of uniform size with variable density maximal centrally extending towards but not reaching limbus. Cornea may be thinned, sensation reduced

178
Q

How to treat Meesmann dystrophy?

A

Treatment other than lubrication not required

179
Q

What are some Bowman layer/anterior stromal dystrophies?

A

Reis-Bucklers corneal dystrophy
Thiel- Behnke corneal dystrophy

180
Q

What is Reis bucklers corneal dystrophy?

A

may be categorized as an anterior variant of granular stromal
dystrophy (GCD type 3) and is also known as corneal basement dystrophy type I (CBD1).

181
Q

What is the inheritance pattern for Reis bucklers corneal dystrophy?

A

AD

Affected gene is TGFB1

182
Q

What does histology of Reis bucklers corneal dystrophy show?

A

Replacement of Bowman layer by connective tissue bands

183
Q

What are the signs and symptoms of Reis bucklers corneal dystrophy?

A

Symptoms- severe RCES childhood and visual impairment may occur

Signs- grey white geographic subepithelial opacities, most dense centrally, increasing in density with age to form reticular pattern
Reduced corneal sensation

184
Q

What is the treatment for Reis bucklers corneal dystrophy?

A

Tx directed at RCES. Excimer keratectomy achieves good outcome in some patients

185
Q

What is Thiel- Behnke corneal dystrophy and what is the inheritance pattern?

A

Also termed honeycomb-shaped corneal dystrophy and corneal
basement dystrophy type II (CBD2); features are generally less
severe than Reis–Bücklers.

*Inheritance. AD; gene TGFB1 and at least one other.

186
Q

What does Thiel- Behnke corneal dystrophy show?

A

Bowman layer ‘curly fibres’ on electron microscopy.

187
Q

What are the symptoms, signs and treatment for Thiel-Behnke corneal dystrophy?

A
  • Symptoms. Recurrent erosions in childhood.
  • Signs. Subepithelial opacities are less individually defined than the granular dystrophy-type lesions seen in Reis–
    Bücklers dystrophy. They develop in a network of tiny rings or honeycomb-like morphology, predominantly involving the central cornea

Treatment not always necessary

188
Q

What are some examples of stromal dystrophies?

A

*Lattice corneal dystrophy TGFB1 type
*Lattice corneal dystrophy gelsolin type
*Granular corneal dystrophy, type 1 (classic)
*Granular corneal dystrophy, type 2
*Macular corneal dystrophy
*Schnyder (crystalline) corneal dystrophy
*François central cloudy dystrophy

189
Q

What is Lattice corneal dystrophy, TGFB1 type, inheritance and histology?

A

usually regarded as the classic form of lattice dystrophy. Clinical variants (e.g. IIIA associated with more than 25 heterozygous mutations in TGFB1 have been described.

*Inheritance. AD; gene TGFB1.
*Histology. Amyloid, staining with Congo red and exhibiting green birefringence with a polarizing filter

190
Q

What are the signs and symptoms of Lattice corneal dystrophy, TGFB1 type?

A

Symptoms- Recurrent erosions end of first decade in classic form when typical stromal signs not yet present. Blurring occurs later
Signs- refractile anterior stromal dots, coalescing into fine filamentous lattice spreading gradually sparing periphery.
Generalised stromal haze may progressively impair vision.

191
Q

How to treat Lattice corneal dystrophy, TGFB1 type?

A

PK or DALK.
Recurrence not uncommon

192
Q

What is Lattice corneal dystrophy, gelsolin type, inheritance and histology?

A

Also known as LCD2 and Meretoja syndrome, this is a systemic
condition rather than a true corneal dystrophy.
*Inheritance. AD; gene GSN.
*Histology shows amyloid deposits in the corneal stroma.

193
Q

What are the signs and symptoms of Lattice corneal dystrophy, gelsolin type?

A

*Ocular symptoms. Ocular irritation and late impairment of vision; erosions are rare.

*Ocular signs
○Sparse stromal lattice lines spread centrally from the periphery.
○Corneal sensation is impaired.

*Systemic features. Progressive cranial and peripheral neuropathy, mask-like facies and autonomic features. Homozygous disease is rare but severe.

194
Q

What is the treatment for Lattice corneal dystrophy, gelsolin type?

A

Keratoplasty may rarely be required in later life.

195
Q

What is Granular corneal dystrophy, type 1 (classic), inheritance and histology?

A

*Inheritance. AD; gene TGFB1. Homozygous disease gives
more severe features.

*Histology. Amorphous hyaline deposits staining bright red
with Masson trichrome

196
Q

What are the symptoms and signs of Granular corneal dystrophy, type 1 (classic)?

A

Symptoms- glare and photophobia with blurring as progression occurs, recurrent erosions uncommon
Signs- Discrete white central anterior stromal deposits resembling sugar granules, breadcrumbs separated by clear stroma. Gradual increase in number and size of deposits with deeper and outward spread with limbal sparing. Gradual confluence and diffuse haze leads to visual impairment. Corneal sensation impaired

197
Q

What is the treatment for Granular corneal dystrophy, type 1 (classic)?

A

by penetrating or deep lamellar keratoplasty is usually required by the fifth decade. Superficial recurrences
may require repeated excimer laser keratectomy.

198
Q

What is Granular corneal dystrophy, type 2, inheritance and histology?

A

Also known as Avellino and combined granular-lattice dystrophy.
*Inheritance. AD; gene TGFB1.
*Histology shows both hyaline and amyloid.

199
Q

What are the symptoms and signs of Granular corneal dystrophy, type 2?

A

*Symptoms. Recurrent erosions tend to be mild. Visual impairment is a later feature.

*Signs are usually present by the end of the first decade in heterozygotes. Fine superficial opacities progress to form stellate or annular lesions, sometimes associated with deeper linear opacities.

200
Q

What is the treatment for Granular corneal dystrophy, type 2?

A

*Treatment is usually not required. Corneal trauma accelerates
progression; refractive surgery is contraindicated.

201
Q

What is macular corneal dystrophy, inheritance and histology?

A

*Inheritance. Autosomal recessive (AR); gene CHST6; the condition is relatively common in Iceland.
*Histology. Aggregations of glycosaminoglycans intra- and
extracellularly; stain with Alcian blue and colloidal iron

202
Q

What are the signs and symptoms of macular corneal dystrophy?

A

*Symptoms. Early (end of first decade) visual deterioration; recurrent erosions are very common.
*Signs
○Dense but poorly delineated greyish-white spots centrally in the anterior stroma and peripherally in the posterior stroma. There is no clear delineation between opacities, which may be elevated.
○Progression occurs together with anterior stroma haze involving the central cornea initially.
○Eventual involvement of full thickness stroma extending to limbus with no clear zone
○Thinning is an early feature with thickening from oedema due to endothelial dysfunction

203
Q

What is the treatment for macular corneal dystrophy?

A

*Treatment. Penetrating keratoplasty. Recurrence is common.

204
Q

What is schnyder (crystalline) corneal dystrophy, inheritance pattern and histology?

A

This is a disorder of corneal lipid metabolism, associated in some
patients with systemic dyslipidaemia. The use of crystalline in the name is no longer recommended as corneal crystals are not a
ubiquitous feature.
*Inheritance. AD; gene UBIAD1.
*Histology. Phospholipid and cholesterol deposits.

205
Q

What are the symptoms and signs of schnyder (crystalline) corneal dystrophy?

A

*Symptoms. Visual impairment and glare.

*Signs
○Central haze is an early feature, progressing to more widespread full-thickness involvement over time
○Subepithelial crystalline opacities are present in only around 50%.
○Prominent corneal arcus is typical and gradually progresses centrally leading to diffuse haze

206
Q

What is the treatment for schnyder (crystalline) corneal dystrophy?

A

excimer keratectomy or corneal transplantation.

207
Q

What is Francois central cloudy dystrophy, inheritance, signs, symptoms and treatment?

A

It is not certain that this entity is a dystrophy; it may be clinically
indistinguishable from the degeneration posterior crocodile
shagreen.
*Inheritance. AD has been reported, but not clearly established.

*Symptoms. Almost always none.

*Signs
○Cloudy greyish polygonal or rounded posterior stromal opacities, most prominent centrally

*Treatment is not required.

208
Q

What are some descemet membrane and endothelial dystrophies?

A

Fuchs endothelial corneal dystrophy
Posterior polymorphous corneal dystrophy
Congenital hereditary endothelial dystrophy

209
Q

What is Fuchs endothelial corneal dystrophy and inheritance pattern?

A

characterized by bilateral accelerated endothelial cell loss. It is more common in women and is associated with a slightly increased prevalence of open-angle glaucoma.

*Inheritance. Most sporadic, with occasional AD inheritance. Mutation in COL8A2 has been identified in an early-onset variant and in the TCF4 gene in most other cases.

210
Q

What are the symptoms and signs of Fuchs endothelial corneal dystrophy?

A

*Symptoms. Gradually worsening blurring, particularly in the morning, due to corneal oedema. Onset is usually in middle age or later.

*Signs
○Cornea guttata: the presence of ‘excrescences’ on Descemet membrane secreted by abnormal endothelial cells
○Specular reflection- tiny dark spots caused by disruption of regular endothelial mosaic. Progression to beaten metal appearance
○Endothelial decompensation gradually leads to central stromal oedema and blurry vision, worse in the morning
○Epithelial oedema in severe cases with microcysts and bullae and discomfort. Rupture of bullae leads to acute pain due to exposed nerve fibres.
○Subepithelial scarring and peripheral vascularization in longstanding cases

211
Q

What is the treatment for Fuchs endothelial dystrophy?

A

*Conservative- NaCl 5%, reduce IOP and hair dryer for corneal dehydration
*Ruptured bullae comfort with BCL, cycloplegia, antibiotics and lubricants
*Posterior lamellar (DSAEK, DMEK) and PK have high success rate
*Eyes with poor visual potential conjunctival flaps, amniotic membrane transplants

212
Q

Why is cataract surgery relevant in Fuchs endothelial dystrophy?

A

may worsen the corneal status because of endothelial cell loss and protective steps should be taken to reduce this.

Modern machines using torsional phacoemulsification use less ultrasound time than the older
machines, which used longitudinal phacoemulsification and are therefore less likely to cause endothelial loss.

A ‘triple procedure’ (combined cataract surgery, lens implantation
and keratoplasty) may be considered in eyes with corneal oedema. Corneal oedema is less likely to occur after
cataract surgery if the central corneal thickness is less than 630–640 µm.

213
Q

What is posterior polymorphous corneal dystrophy, inheritance symptoms, signs and treatment?

A

There are three forms of posterior polymorphous dystrophy, PPCD1–3. Associations include iris abnormalities, glaucoma and
Alport syndrome. The pathological basis involves metaplasia of endothelial cells.

*Inheritance is usually AD. The gene VSX1 has been implicated in PPCD1, PPCD2 is caused by mutations in COL8A2 and PPCD3 by ZEB1 mutations.

*Symptoms. Usually absent, with incidental diagnosis.

*Signs. Subtle vesicular, band-like or diffuse endothelial lesions

*Treatment is not required.

214
Q

What is Congenital Hereditary Endothelial Dystrophy (CHED)?

A

Congenital hereditary endothelial dystrophy (CHED) is a rare
dystrophy in which there is focal or diffuse thickening of Descemet
membrane and endothelial degeneration. CHED2 is a more
common and more severe form than CHED1 and is occasionally
associated with deafness (Harboyan syndrome).

215
Q

What is the inheritance pattern for CHED?

A

○CHED1 is AD with the gene locus on chromosome 20. CHED1 may not be distinct from PPCD.

○CHED2 is AR; gene SLC4A11.

216
Q

What are the symptoms, signs and treatment for CHED?

A

*Symptoms
Photophobia and watering are common in CHED1, but not in CHED2.

*Signs
○Corneal clouding and thickening are neonatal in CHED2 and develop during the first year or two in
CHED1.
○Visual impairment is variable and visual acuity may surpass that expected from the corneal appearance.
○Nystagmus is more common in CHED2.

*Treatment. Lamellar or penetrating keratoplasty.

217
Q

What is arcus senilis?

A

Arcus senilis (gerontoxon, arcus lipoides) is the most common
peripheral corneal opacity. Frequently occurs in elderly. Associated with dyslipidaemia in younger individuals

Signs:
Stromal lipid deposition initially in superior and inferior perilimbal cornea progressing circumferentially to form a band 1mm wide. Band wider in vertical than horizontal meridian. Central border is diffuse and peripheral edge is sharp separated from limbus by clear zone that may undergo mild thinning.

218
Q

What is Vogt limbal girdle?

A

An innocuous condition that is present in upto 60% of individuals over 40
Consists of whitish crescentic limbal bands composed of chalk-like flecks centred at 9 and/or 3 o’clock, more often nasally. There may be irregular central extension.

Type 1: variant of band keratopathy with swiss cheese hole pattern and clear area separating lesion from scleral margin

Type 2: more prevalent and distinguished by absence of holes and juxtalimbal clear zone. Histological changes similar to pinguecula and pterygium

219
Q

What are corneal farinata?

A

a visually insignificant condition characterized by bilateral, minute, flour-like deposits in the deep stroma, most prominent centrally

220
Q

What is crocodile shagreen?

A

characterized by asymptomatic, greyish-white, polygonal stromal opacities separated by relatively clear spaces.

The opacities most frequently involve the anterior two-thirds of the stroma (anterior crocodile shagreen), although on occasion they may be found more posteriorly (posterior
crocodile shagreen). It may be indistinguishable from François
central cloudy dystrophy

221
Q

What is west indian punctate keratopathy?

A

an unusual condition of unknown cause that is seen in elderly asymptomatic individuals, generally of West Indian origin. Males are more affected than females. Affects one eye but can be bilateral.

Lesions are round 0.5mm or less located at level of bowman membrane extending into superficial stroma. Usually have a central dot intensely white in colour surrounded by paler halo merging with adjacent cornea. No treatment required

222
Q

What is primary lipid keratopathy?

A

rare and occurs apparently
spontaneously. It is characterized by white or yellowish, often with a crystalline element, stromal deposits consisting of cholesterol, fats and phospholipids and is not associated with vascularization

223
Q

What is secondary lipid keratopathy?

A

more common and associated with previous ocular injury or dis1ease that has resulted in corneal vascularization. The most common causes are herpes simplex and herpes zoster keratitis

224
Q

What is the treatment for lipid keratopathy?

A

aimed at medical control of the
underlying inflammatory disease. Other options include:
○Photocoagulation or needle cautery (suture needle grasped with cautery forceps) of feeder vessels.
○Penetrating keratoplasty may be required in advanced but quiescent disease, though vascularization, thinning and reduced sensation may affect the outcome.

225
Q

What is band keratopathy and what causes it?

A

age-related deposition of calcium
salts in the Bowman layer, epithelial basement membrane and anterior stroma.

Causes: chronic anterior uveitis (mainly in children with JIA), glaucoma, phthisis bulbi, silicone oil in AC, chronic corneal oedema, severe chronic keratitis, Age related affecting otherwise healthy individuals, Metabolic (metastatic calcification) secondary to hypercalcemia is uncommon.
Hereditary causes are familial and ichthyosis

226
Q

What are the signs of band keratopathy?

A

○Peripheral interpalpebral calcification with clear cornea separating the sharp peripheral margins of the band from
the limbus
○Gradual central spread to form a band-like chalky plaque containing transparent small holes and occasionally clefts.
○Advanced lesions may become nodular and elevated with
considerable discomfort due to epithelial breakdown.

227
Q

What is the treatment for band keratopathy?

A

Treat if vision threatened or eye uncomfortable.
Chelation simple for mild cases. Corneal epithelium overlying opacity and solid layer of calcification is scraped off. Cornea then rubbed with cotton tipped applicator dipped in EDTA until all calcium removed. 15-20 mins for this step. >1 session may be needed. Re-epithelialization takes many days.

○Other modalities: diamond burr, excimer laser keratectomy and lamellar keratoplasty

228
Q

Whats is spheroidal degeneration and what is seen on histology?

A

Spheroidal degeneration (Labrador keratopathy, climatic droplet
keratopathy) typically occurs in men whose working lives are spent outdoors. Ultraviolet exposure is likely to be an aetiological factor. The condition is relatively innocuous but visual impairment may occur. A secondary form can follow inflammation or injury.

*Histology. Irregular proteinaceous deposits in the anterior stroma that replace the Bowman layer.

229
Q

What are the signs for Spheroidal degeneration?

A

○Amber-coloured granules in the superficial stroma of the peripheral interpalpebral cornea.
○Increasing opacification, coalescence and central spread.
○Advanced lesions commonly protrude above the corneal surface and the surrounding stroma is often
hazy. The conjunctiva can be involved.

230
Q

What is the treatment for spheroidal degeneration?

A

Protection against ultraviolet damage with sunglasses and superficial keratectomy or lamellar keratoplasty in a minority.

231
Q

What is Salzmann nodular degeneration?

A

Salzmann nodular degeneration consists of nodules of hyaline tissue,
usually located anterior to the Bowman layer. It can occur in any
form of chronic corneal irritation or inflammation such as trachoma,
dry eye, chronic blepharitis and chronic allergic keratoconjunctivitis.

232
Q

What are the signs of Salzmann nodular degeneration?

A

○Superficial stromal opacities progressing to elevated whitish or blue–grey nodular lesions that may be round or elongated

○The base of a nodule may be associated with pannus and epithelial iron deposition.

233
Q

What is the treatment for Salzmann nodular degeneration?

A

Lubrication together with control
of the cause. Removal is via manual superficial keratectomy – the lesions can often be ‘peeled’ away and the surface flattened with a diamond burr.
Adjunctive mitomycin C applied for 10
seconds with a sponge may reduce the recurrence rate, though some authorities restrict its use to reoperations. Excimer laser
phototherapeutic keratectomy or lamellar keratoplasty are occasionally required.

234
Q

What is advancing wave like epitheliopathy, risk factors and treatment?

A

an irregular advancing epithelial plaque encroaching gradually on
the cornea, typically originating at the superior limbus and sometimes extending circumferentially from a pterygium. vision may be affected with central involvement.

risk factors include contact lens wear, certain contact lens solutions, topical glaucoma medication, prior ocular surgery and some skin conditions such as rosacea.

Treatment of the cause may be curative, but otherwise is with 1%
silver nitrate solution to the adjacent limbus or cryotherapy (1–2
seconds twice) to the limbus and abnormal tissue. Distinction
from neoplasia may occasionally warrant impression cytology or
excision biopsy

235
Q

What are some examples of Metabolic keratopathy?

A

Cystinosis
Mucipolysaccharidoses
Wilson disease
Lecithin Cholestrol Acyltransferase deficiency
Immunoprotein deposition
Tyrosinaemia type 2
Fabry disease

236
Q

What is cystinosis?

A

a rare AR (gene: CTNS) lysosomal storage disorder characterized by widespread tissue deposition of cystine crystals, leading to paediatric renal failure and a range of other severe systemic problems.

Keratopathy may develop in the first year, with progressive deposition of crystals in the cornea and conjunctiva associated with photophobia, epithelial erosions and visual impairment.

Systemic treatment is
with cysteamine, which can be given in eye drop form to reverse
corneal crystal formation.

237
Q

What is mucopolysaccharidoses?

A

a group of lysosomal storage disorders involving enzyme dysfunction along the pathways for breakdown of glycosaminoglycans, long chain carbohydrates formerly known as mucopolysaccharides.
Altered metabolites accumulate intracellularly in various tissues.
Inheritance is mainly AR.

Keratopathy comprises
punctate corneal opacification and diffuse stromal haze and occurs in all MPS except Hunter and Sanfilippo.
Ocular features may include pigmentary retinopathy and optic
atrophy.

238
Q

What is wilson disease?

A

(hepatolenticular degeneration) is a rare condition involving the widespread abnormal deposition of copper in tissues. It is caused by a deficiency of caeruloplasmin, the major copper-carrying blood protein.
Presentation is with liver disease,
basal ganglia dysfunction or psychiatric disturbances.

A Kayser–Fleischer ring is present in 95% of patients with neurological signs and consists of a brownish-yellow zone of fine copper dusting in
peripheral Descemet membrane

deposits are preferentially
distributed in the vertical meridian and may disappear with penicillamine therapy.

Anterior capsular sunflower cataract is seen in some patients

239
Q

What is LCAT?

A

Lecithin-cholesterol-acyltransferase (LCAT) deficiency is a disorder of lipoprotein metabolism that has complete (Norum disease, with systemic manifestations including renal failure) and partial (fish eye disease, causing only corneal opacification) forms that are both AR (gene: LCAT)

Keratopathy is characterized by numerous minute greyish dots throughout the stroma, often concentrated in the periphery in an arcus-like configuration

240
Q

What is immunoprotein deposition?

A

Diffuse or focal immunoprotein deposition is uncommon manifestation of several systemic diseases, including multiple
myeloma, Waldenström macroglobulinaemia, monoclonal
gammopathy of unknown cause, some lymphoproliferative
disorders and leukaemia.

Corneal involvement may be the earliest manifestation. Bands of punctate flake-like opacities are seen,
mostly at the level of the posterior stroma. Treatment is that of the underlying disease. Severe corneal involvement may require corneal transplantation.

241
Q

What is Tyrosinaemia type 2?

A

Tyrosinaemia type 2 (oculocutaneous tyrosinaemia, Richner–Hanhart syndrome) is a very rare AR disease (gene: TAT) in which an enzyme deficiency leads to elevated plasma tyrosine levels.

Ocular involvement may occasionally be the presenting feature.
Painful palmar and plantar hyperkeratotic lesions and variable
CNS involvement are seen.
A bilateral pseudodendritic keratitis
with crystalline edges often begins in childhood and causes photophobia, watering and redness.

242
Q

What is Fabry disease?

A

X-linked lysosomal storage disorder caused by a deficiency of the enzyme alpha-galactosidase A that leads
to abnormal tissue accumulation of a glycolipid. All males with the gene develop the disease and some heterozygous females.

Ocular manifestations include
white to golden-brown corneal opacities in a vortex pattern (75%)
that may be the first feature of the disease facilitating early intervention, wedge- or spoke-shaped posterior cataract (Fabry cataract), conjunctival vascular tortuosity (corkscrew
vessels) and aneurysm formation and retinal vascular tortuosity

243
Q

What are the optical therapeutic indications for CL use?

A

Irregular astigmatism associated with keratoconus corrected with rigid CL
Superficial corneal irregularities neutralised by rigid CL with smoother optical surface. Only if irregularities are not too severe
Anisometropia in which BV cannot be achieved by specs due to anisekonia after cataract surgery with high refractive correction

244
Q

What are the ‘promotion of epithelial healing’ therapeutic indications for CL use?

A

Persistent ED- often heal if epithelium protected from constant rubbing of lids allowing hemidesosomal attachments to BM

Recurrent corneal erosions associated with BM dystrophy may require long term CL wear to reduce recurrence.

245
Q

What are the ‘pain relief’ therapeutic indications for CL use?

A

Bullous keratopathy managed with soft BCL relieving pain by protecting exposed corneal nerve endings from shearing forces of lids when blinking. Lens can flatten bullae into small cysts

Filamentary keratopathy resistant to topical therapy will achieve some comfort from soft CL use.

Other indications- thygeson superficial punctate keratitis, protect corneal epithelium from aberrant lashes in trichiasis

246
Q

What are the ‘preservation of corneal integrity’ therapeutic indications for CL use?

A

Descemetocoele- temporarily capped with tight fitting large diameter soft or scleral lens to prevent perforation and encourage healing.

Splinting and apposition of the edges of small corneal wound achieved by CL. Larger perforations sealed with glue then BCL

247
Q

What are some complications of CL use?

A

*Mechanical and hypoxic keratitis
*Immune response keratitis
*Toxic keratitis
*Suppurative keratitis (lowest risk for rigid lenses)
*CL associated giant papillary conjunctivitis

248
Q

What is the normal neonatal corneal diameter vs adult corneal diameter?

A

The normal neonatal corneal diameter is 10 mm and the adult
diameter of 12 mm is usually reached by the age of 2 years.

249
Q

What is Microcornea?

A

Microcornea is a rare autosomal dominant (sometimes sporadic)
unilateral or bilateral condition in which the horizontal corneal
diameter is 10 mm or less over 2 years of age or less than 9 mm in the newborn.

The cornea is steep on keratometry. There may be hypermetropia and a shallow anterior chamber but other dimensions are normal.

Ocular associations include glaucoma (angle-closure and open angle), congenital cataract, leukoma, persistent fetal vasculature, coloboma, optic nerve hypoplasia, aniridia and nanophthalmos. Systemic associations have been reported. Refractive error and amblyopia should
be managed appropriately.

250
Q

What is Microphthalmos?

A

a condition in which the entire eye is small, with an axial length at least two
standard deviations below the mean for age.

Simple or pure microphthalmos (nanophthalmos) refers to an eye that is structurally normal apart from a short length and complex microphthalmos to eyes with other features of dysgenesis for example: a coloboma or orbital cyst and a range of other ocular anomalies

Vision is variably affected, in conjunction with severity. It is typically sporadic but mutations in numerous genes have been implicated. Around 50% of cases may be associated with
systemic abnormalities, including of the CNS. Potential environmental causes include fetal alcohol syndrome and intrauterine infections.

251
Q

What is Nanophthalmos?

A

the entire eye is small with an axial length of less than 20 mm. Both eyes are usually affected. Ocular associations include glaucoma (especially angle-closure as the lens is large relative to the size of the eye), hypermetropia, ametropia, amblyopia and strabismus.

In childhood, management of refractive error and amblyopia are critical. Surgery for glaucoma is particularly hazardous and can result in aqueous misdirection and choroidal
effusion (‘small eye–big trouble’). Lens extraction is technically challenging, but has the advantage of deepening the anterior chamber and reducing the refractive error if a suitable high-power lens implant is inserted.

252
Q

What is Anophthalmos?

A

Anophthalmos (anophthalmia) refers to the complete absence of
any visible globe structure though a microphthalmic remnant or cyst may be present. It is associated with
other abnormalities such as absence of extraocular muscles, a short conjunctival sac and microblepharon. Causative factors are probably broadly similar to those of microphthalmos.

253
Q

What is megalocornea?

A

Rare bilateral non-progressive condition that is usually X-linked recessive. Approximately 90% of affected individuals are male. The adult horizontal corneal diameter is 13 mm or more, with a very deep anterior chamber.

There is usually high myopia and astigmatism but normal corrected visual acuity. Lens subluxation may occur due to zonular stretching and
pigment dispersion syndrome may occur. Numerous systemic associations have been reported.

254
Q

What is sclerocornea?

A

very rare, usually bilateral, condition that may be associated with cornea plana.
Sporadic cases are common, but a milder form can be inherited as AD and a more severe form as AR. Peripheral corneal opacification, with no visible border between the sclera and cornea, confers the appearance of apparently reduced corneal diameter in mild–moderate disease. Occasionally the entire cornea is involved

255
Q

What is cornea plana?

A

an extremely rare bilateral condition in which the cornea is flatter than normal – the radius of curvature is larger.
There is a corresponding reduction in refractive power resulting in high hypermetropia.

Two forms are described, cornea plana 1 (CNA1) being milder than cornea plana 2. Associated ocular
abnormalities are common.

256
Q

What is keratectasia?

A

a very rare, usually unilateral, condition thought to be the result of intrauterine keratitis and perforation.

It is characterized by protuberance between the eyelids of a severely
opacified and sometimes vascularized cornea. It is often associated with raised IOP.

257
Q

What is posterior keratoconus?

A

a sporadic condition in which there is
unilateral non-progressive increase in curvature of the posterior
corneal surface.
The anterior surface is normal and visual acuity relatively unimpaired because of the similar refractive indices of the cornea and aqueous humour. Generalized (involvement of
the entire posterior corneal surface) and localized (paracentral or central posterior indentation – types are described.

258
Q
A

kanski- frcophth part 2 (11 decks)

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