BCSC Cornea Flashcards
How long does it take eyelashes (cilia) to re-grow when pulled out?
2 months
How long does it take eyelashes (cilia) to re-grow when cut?
2 weeks
What type of gland are the glands of Moll?
apocrine sweat glands
What type of gland are the glands of Zeis?
sebaceous glands
What are the different morphologies (and their locations) of the conjunctival epithelium?
1) stratified cuboidal over tarsus
2) columnar in the fornices
3) squamous over the globe
What is the blood supply of the bulbar conjunctiva?
anterior ciliary arteries branching from the ophthalmic artery
What is the blood supply of the palpebral conjunctiva?
It is the same as the blood supply of the eyelids
What is the sensory innervation of the conjunctiva?
Several branches of V1 (lacrimal, supraorbital, supratrochlear, infraorbital)
What are the components of the lacrimal functional unit?
1) lacrimal glands
2) ocular surface (cornea, conj, meibomian glands)
3) eyelids
4) the innervation of all the above
What is the average blink rate in adults?
Approximately 15 times/minute
What are the three (traditional) components of the tear film?
1) lipid
2) aqueous
3) mucus
From which cells is the mucus content of the tear film secreted?
conjunctival goblet cells
What is the horizontal diameter of the adult cornea?
11-12 mm
What is the vertical diameter of the adult cornea?
10-11 mm
What is the average radius of curvature of the central cornea?
7.8mm
What proportion of the refractive power of a normal human eye is contributed by the cornea?
74% (43.25 D of 58.60 D)
What are the factors present in the corneal tear film?
EGF, lactoferrin, defensins, IgA, IL1-RA, TGF-beta, TIMP 1, MMP-9
From where does the sub-basal epithelium plexus of corneal nerves originate?
Long ciliary nerves
What are the neurotransmitters present in the cornea?
1) acetylcholine
2) catecholamines
3) substance P
4) calcitonin gene-related peptide
5) neuropeptide Y
6) intestinal peptide
7) galanin
8) methionine-enkephalin
What is the histologic type of the corneal epithelium?
Stratified squamous epithelial cells
What percent of the corneal thickness does the corneal epithelium make up?
5% to 10%
How do superficial epithelial cells prevent penetration of the tear film into the stroma?
with tight junctions in between superficial epithelial cells
How many days does it take for a proliferating perilimbal basal epithelial cell to differentiate into a superficial epithelial cell?
7-14 days
What is the composition of the corneal epithelial basement membrane?
Type IV collagen, laminin
What do keratocytes do?
They are flattened fibroblasts, located between collagen lamellae in the corneal stroma, and continually digest and manufacture stromal molecules
Is Bowman layer acellular?
yes
What are the primary collagen types seen in the corneal stroma?
Types I, V, and VI
How does the lattice arrangement of collagen fibrils in the stroma contribute to corneal transparency?
It acts as a diffraction grating, which reduces light scattering by means of destructive interference
Does the refractive index of the cornea increase or decrease moving from anterior to posterior?
Decrease
How does the hydration status of the cornea vary from anterior to posterior?
Increasingly hydrated posteriorly
Of what is the Bowman layer composed?
Type I collagen fibrils (it is stronger than the stroma proper)
Of what is sclera composed?
Type I collagen, proteoglycans, elastin, and glycoproteins
What are the 3 major types of direct illumination?
1) Diffuse illumination
2) Focal illumination
3) Specular reflection
What are the 3 major types of indirect illumination?
1) Proximal illumination
2) Sclerotic scatter
3) Retroillumination
How do guttae and keratic precipitates appear on specular reflection?
Non-reflective dark areas
Sclerotic scatter takes employs what optical phenomenon?
Total internal reflection
Sclerotic scatter is effective for identifying which corneal findings?
1) epithelial edema
2) stromal infiltration
3) cornea verticillata
How is tear breakup time measured?
1) Instill fluorescein
2) Ask patient to blink 2-3 times
3) Ask patient to hold eye open without blinking and use timer
4) Amount of time required for formation of dry spot is the TBUT
What TBUT is considered normal?
> = 10 seconds
How is a Seidel test performed?
1) Apply fluorescein with a moistened strip or concentrated drop to site of suspected leakage
2) View with cobalt blue filter, and look for clear fluid streaming through the dye
Where is true positive fluorescein staining seen?
Areas of epithelial defects
Where is staining with Rose Bengal or Lissamine Green seen?
Epithelial cells for which the protective mucin coating has been disrupted
Rose Bengal and Lissamine Green are useful for detecting which neoplasm in particular?
Corneal intraepithelial neoplasia (CIN)
What does the “Basic Secretion Test” measure?
basic (basal) tearing rate
How is the Basic Secretion Test performed?
1) Topical Anesthetic
2) Test Strip x 5 minutes
low (aqueous tear deficiency)
3-10mm equivocal
How is Schirmer I performed?
Same as Basic Secretion Test, but NO anesthetic
1) Test strip x 5 minutes
low (aqueous tear deficiency)
How is Schirmer II performed?
1) Topical Anesthetic
2) Nasal mucosa irritation with cotton swab
3) Test Strip x 2 minutes
deficient reflex tearing
What does Schirmer I measure?
Basal + Reflex tearing
What does Schirmer II measure?
Reflex tearing (after stimulation)
How is Schirmer II different from Schirmer I?
Schirmer II adds topical anesthetic and nasal irritation, and is only for 2 minutes. Schirmer II tests only reflex tearing, as opposed to reflex + basal (Schirmer I).
Does tear film hyperosmolarity indicate dry eye?
Yes
What do reduced levels of tear film lysozyme or lactoferrin indicate?
Dry eye
What is impression cytology?
The harvesting of cells from the ocular surface with a pice of filter paper for microscopic evaluation and/or flow cytometry.
What is the average central corneal thickness of the normal adult human cornea?
540 microns
Where is the thinnest zone of the cornea usually located?
1.5mm temporal to the geographic center
Increase in corneal thickness by what percentage is required for Descemet folds to be seen?
10%
What is the corneal apex?
The steepest point on the cornea
What is the corneal vertex?
The point at the intersection of the patient’s line of fixation and the corneal surface
What is the power of the posterior corneal surface?
-6 D
Total power = 43 D = 49 D - 6 D
What is the derived corneal refractive index normally used for computing central corneal power?
1.3375
Do mires of a placido disc-based topographer appear closer together or farther away in steep portions of the cornea?
Closer together
What are the three commonly used methods to describe corneal curvature?
1) axial curvature
2) instantaneous radius of curvature
3) mean curvature
What are factors that may affect the accuracy of corneal topography?
1) misalignment
2) test-to-test variation
3) focusing errors
4) tear-film effects
5) distortions
6) variation in area of coverage
What are common situations in which corneal topography is used?
1) IOL calculations
2) Contact lens fitting
3) Refractive surgery
4) Evaluation of keratoconus or other corneal ectasias
What is the normal axial resolution of ultrasound biomicroscopy (UBM)?
35 microns to 70 microns
Is UBM able to provide visualization of internal structures such as the iris in “eight-ball” hyphema?
Yes
What is the axial resolution of anterior segment OCT at present?
5 microns to 10 microns
What are the 4 forms of confocal microscopy that have been described for clinical use?
1) tandem-scanning
2) slit scanning
3) laser scanning
4) single-sided disc
What is the axial resolution of laser scanning confocal microscopes?
1-2 microns
What is the normal endothelial cell density in adults?
2400 cells/mm^2
What is the normal endothelial cell density in children?
3500 cells/mm^2
What is polymegathism?
Increased variation in individual endothelial cell areas
How can retinoscopy detect irregular astigmatism?
By demonstrating nonlinear or multiple reflexes that cannot be completely neutralized with a spherocylindrical lens
Where are conjunctival papillae most easily seen?
in the palpebral conjunctiva in regions where fibrous septa anchor the conjunctiva to the tarsus
What are conjunctival papillae?
Dilated, telangiectatic conjunctival blood vessels surrounded by edema and a mixed inflammatory cell infiltrate
What are conjunctival follicles?
Focal lymphoid nodules with accessory vascularization
Does chlamydial conjunctivitis usually present with conjunctival follicles or papillae?
Follicles
Is drug-induced conjunctivitis usually follicular or papillary?
Follicular
What are three common causes of conjunctival granulomas?
1) Cat-scratch disease
2) Sarcoid
3) Foreign body
How large must a conjunctival papilla be to be classified as “giant?”
Diameter > 0.3mm
What do dot and strand keratic precipitates usually comprise?
Fibrin
What do punctate keratic precipitates usually comprise?
Neutrophils and lymphocytes
What do mutton-fat KPs usually comprise?
macrophages
Incorporation of what materials may lead to dark pigmentation of a corneal opacity?
melanin or iron salts
From where does corneal NV usually arise?
Limbal blood vessels in the palisades of Vogt
What is subepithelial fibrous ingrowth into the peripheral cornea called?
Pannus
What are the core mechanisms thought to be involved in dry eye?
1) Hyperosmolarity
2) tear-film instability
3) Inflammation
What impact does tear hyperosmolarity have on the corneal epithelium?
Induction of inflammation and subsequent disruption of tight junctions between epithelial cells
What are the two common classifications of Dry Eye?
1) Aqueous tear deficiency
2) Evaporative
What are common causes of tear-film instability?
1) MGD
2) Vitamin A deficiency
3) contact lens wear
4) Exposure
5) antihistamines
6) topical medications with preservatives such as BAK
What is the mechanism of aqueous tear deficiency in Sjogren syndrome?
T-cell mediated inflammation of the lacrimal gland –> diminished tear production and propagation of inflammatory mediators on the ocular surface
A tear meniscus of less than what height is considered abnormal?
< 0.3 mm
Of what are the filaments in ATD composed?
Strands of epithelial cells attached to the corneal surface over a core of mucus
What is the appearance of the meibomian gland in MGD?
The meibomian gland orifices may pout or show metaplasia, with a white plug of keratin extending through the glandular orifice
How does atrophy of the meibomian glands appear?
absence of the vertical lines of the meibomian glands, best seen with transillumination of the everted eyelid or infrared photography
Which classes of systemic medications are known to be associated with dry eye?
1) diuretics
2) antihistamines
3) anticholinergics
4) psychotropics
What are demulcents?
Polymers added to artificial tear solutions that can briefly substitute for glycoproteins absent in late stage dry eye.
What percent of patients with moderate to severe ATD benefit from the use of topical cyclosporine A?
50%
What is required for the generation of autologous serum tears?
3-4 red top tubes of blood
Patients with filamentary keratopathy associated with dry eye are often treated with which agent?
topical acetylcysteine 10%
Are cholinergic agents approved for the stimulation of tear secretion in Sjogren syndrome?
not presently in the US, but pilocarpine and cevimeline are approved for the treatement of xerostomia
Which medications can be effective in MGD?
1) topical azithromycin
2) topical corticosteroids
3) systemic tetracyclines (usually doxycycline 100mg bid x 3-4 weeks, tapering to 40-100mg daily)
What impact has omega-3 supplementation been seen to have on MGD?
1000mg tid x 1 year improved symptoms, tear-film stability, and meibomian secretions; other studies have demonstrated increases in tear production, which would indicate a potential role in therapy for ATD as well
With which peptides is rosacea thought to be associated?
Cathelicidin antimicrobial peptides
What are cathelicidins?
Peptides that cause neutrophil recruitment, angiogenesis, and cytokine release
What are the common ocular findings in rosacea?
1) eyelid margin telangiectasia
2) meibomian gland distortion
3) blepharitis
What are severe ocular manifestations of rosacea?
1) chronic conjunctivitis
2) marginal corneal infiltrates
3) sterile corneal ulceration
4) episcleritis
5) iridocyclitis
What is the mainstay of treatment of the ocular manifestations of rosacea?
tetracyclines
What are the 3 primary forms of blepharitis?
1) Staphylococcal
2) MGD
3) Seborrheic
What is poliosis?
Condition of having white eyelashes
In which form(s) of blepharitis is eyelash loss or whitening common?
Staphylococcal blepharitis
With what is staphylococcal blepharitis often associated?
1) matted golden crusts and ulcers on the anterior eyelid margin
2) inferior PEE
3) marginal corneal infiltrates
4) conj or corneal phlyctenules
What is phlyctenulosis?
a local corneal or conjunctival inflammation thought to be due to cell-mediated or delayed hypersensitivity response to S. aureus or M. tuberculosis
What is the common appearance of a phlyctenule?
small, rounded, elevated, gray or yellow, hyperemic, focal inflammatory nodule present at or near the limbus, accompanied by a zone of engorged vessels
What are hordeola?
Red, painful, tender, nodular masses at the eyelid margin related to glands at the eyelid margin
Hordeola of the anterior eyelid margin (external hordeola) are related to which glands?
Glands of Zeis
Hordeola on the posterior eyelid margin (internal hordeola) are related to which glands?
Meibomian glands
What are chalazia?
chronic lipgranulomatous nodules involving either the meibomian glands or the glands of Zeis
What are options for management of hordeola?
Warm compresses, lid hygiene, doxycycline
Intralesional injection of what type of drug can be useful in treatment of recalcitrant small chalazia?
corticosteroids (0.1-0.2 mL triamcinolone 40mg/mL)
What are the clinical features of floppy eyelid syndrome?
1) lax superior tarsus that everts with minimal force
2) papillae on superior palpebral conjunctiva
3) mucus discharge
4) PEE
Is floppy eyelid syndrome more common in obese or normal BMI individuals?
Obese individuals
What are possible treatments for floppy eyelid syndrome?
eye shield, taping eyelids closed at night, surgical eyelid tightening
What are the clinical features of superior limbic keratoconjunctivitis (SLK)?
1) papillary reaction of superior tarsal conj
2) injection and thickening of superior bulbar conj
3) hypertrophy of superior limbus
4) punctate staining of superior bulbar conj
5) superior filamentary keratopathy
With which autoimmune disease is SLK associated?
autoimmune thyroid disease (Graves disease)
Is SLK more common in men or women?
Women (20-70 years old)
Is SLK usually self-limited?
Yes
What is the proposed mechanism of action of doxycycline in treating recurrent corneal erosion?
Inhibition of matrix metalloproteinases
What are surgical therapies for recurrent corneal erosion?
1) stromal micropuncture
2) epithelial debridement
3) PTK
What is the goal of stromal micropuncture in recurrent corneal erosion?
microcicatrization between epithelium, Bowman layer, and stroma
What are the key aspects of management of neurotrophic keratopathy?
1) remove corneal sensation reducing meds
2) maintain lubrication (with PFATs, possibly scleral contact lens to create fluid reservoir)
3) eliminate any exposure (possibly with tarsorrhaphy)
4) reduce mucus production
5) prevent bacterial infection (with antibiotics, epi defect closure with AMT)
6) reduce MMP action (possibly with tetracyclines)
7) restore trophic factors (possibly with autologous serum tears)
What is trichiasis?
an acquired condition in which eyelashes emerging from their normal origin curve inward toward the cornea
What is distichiasis?
a condition in which an extra row of lashes emerges from the ducts of the meibomian glands
What are the epithelial changes seen with topical anesthetic use?
1) Inhibition of epithlelial migration and division
2) loss of microvilli
3) reduction of desmosomes
What are dellen?
saucer-like depressions in the corneal surface, usually related to an are of dehydrated corneal stroma
What percent of the corneal limbus must be intact to ensure normal ocular resurfacing?
25-33%
Mutation in which gene can be a cause of primary limbal stem cell deficiency?
PAX6 gene (aniridia)
What are the major classes of causes of limbal stem cell deficiency (LSCD)?
1) Idiopathic
2) Traumatic
3) Iatrogenic
4) Autoimmune
5) Acquired eye disease
6) Congenital eye disease
Which topical medications can cause LSCD?
1) pilocarpine
2) beta blockers
3) antibiotics
4) antimetabolites
What are the surgical therapies for LCSD?
1) limbal or conjunctival autograft
2) limbal allograft
3) keratoprosthesis
What is the difference between primary and secondary Sjogren syndrome?
Primary Sjogren syndrome patients do not have a well-defined connective tissue disease, while those with Secondary Sjogren syndrome do.
What is the most commonly associated connective tissue disease in secondary Sjogren syndrome?
RA
What are common ocular findings in the icthyoses?
1) eyelid scaling (hyperkeratosis)
2) cicatricial ectropion
3) conjunctival thickening
What are the characteristics of an ectodermal dysplasia?
1) presence of abnormalities at birth
2) nonprogressive course
3) involvement of the epidermis plus at least one of the hair, nails, teeth or sweat glands
What are the ocular manifestations of Xeroderma Pigmentosum?
1) photophobia
2) tearing
3) blepharospasm
4) features of keratoconjunctivitis sicca
Vitamin A deficiency results in dryness associated with loss of which cells?
The conjunctival goblet cells, thus causing a reduction in mucus production
What is a Bitot spot?
a superficial foamy gray triangular area on the bulbar conjunctiva consisting of keratinized epithelium, inflammatory cells, debris, and Corynebacterium xerosis. The Bitot spot is seen in Vitamin A deficiency
What function does lactoferrin serve in the tear film?
Lactoferrin inhibits bacterial metabolism and facilitates tear antibody function and complement activation
What function does lysozyme serve in the tear film?
Tear lysozyme degrades bacterial cell walls
What function does beta-lysin serve in the tear film?
Tear beta-lysin disrupts bacterial plasma membranes
What are the predominant ocular flora in the an infant?
S. aureus, S. epidermidis, strep species, E. coli
How does acanthamoeba adhere to the corneal surface?
Through the expression of a mannose-binding protein that attaches to surface epithelial cells
Which bacteria are known to be able to overcome an intact corneal epithelium?
1) N. gonorrhoeae
2) N. meningitidis
3) C. diptheriae
4) Shigella species
5) H. flu biotype III
6) L. monocytogenes
What are two factors produced by psuedomonas to invade the cornea?
elastase and alkaline protease
What are the recommended culture media for aerobic bacteria in the setting of a microbial keratitis?
1) blood agar
2) chocolate agar
3) thioglycollate broth
What are the recommended culture media for anaerobic bacteria in the setting of a microbial keratitis?
1) Anaerobic blood agar
2) Phenylethyl alcohol agar in anaerobic chamber
3) Thioglycollate or meat broth
What are the recommended culture media for mycobacteria in the setting of a microbial keratitis?
1) blood agar
2) Lowenstein-Jensen agar
What are the recommended culture media for fungi in the setting of a microbial keratitis?
1) Blood agar
2) Sabourad’s agar
3) Brain-heart infusion agar
What are the recommended culture media for acanthamoeba in the setting of a microbial keratitis?
1) Non-nutrient agar with bacterial overlay
2) blood agar
3) Buffered charcoal-yeast extract agar
For which type of microbial keratitis is a Giemsa stain most often recommended?
Acanthamoeba keratitis
Are enveloped viruses (such as HSV) susceptible to damage by alcohols and general-use antiseptics?
Yes
What is the most common systemic manifestation of primary HSV infection?
URI
What is the typical manifestation of primary ocular HSV infection?
blepharoconjunctivitis
What are the classic signs of an acute primary HSV ocular infection?
1) cutaneous or eyelid margin vesicles (or ulcers on the bulbar conjunctiva)
2) dendritic epithelial keratitis
What is a common manifestation of an adenoviral keratoconjunctivitis that is rarely seen in HSV ocular infection?
conjunctival membranes or pseudomembranes
What is the mechanism of recurrent HSV ocular infection?
1) reactivation of latent virus present in an infected sensory ganglion (trigeminal ganglion)
2) transport of virus to sensory nerve endings
3) re-infection
Is recurrent ocular HSV usually unilateral or bilateral?
Unilateral (97%)
What are the common symptoms of a patient with HSV epithelial keratitis?
1) FBS
2) light sensitivity
3) redness
4) blurred vision
What is a distinguishing characteristic of the dendritic ulcers associated with HSV epithelial keratitis?
terminal bulbs
Where and how does an HSV corneal ulcer stain?
1) bed of ulcer stains with fluorescein (loss of epithelial tight junctions)
2) edges of ulcer stain with rose bengal/lissamine green (epithelial devitalization/loss of mucin binding at site of active viral replication)
The application of steroids to an active HSV epithelial keratitis can result in what?
Enlargement of a dendritic ulcer into a geographic ulcer
What are tests that can be done to confirm HSV as a cause of a dendritic epithelial keratitis?
1) intranuclear inclusions on corneal scrapings
2) tissue culture
3) ELISA
4) PCR
What treatment options are available for HSV epithelial keratitis?
1) technically, observation, as it is generally self-limited
2) epithelial debridement
3) topical antiviral therapy (topical trifluridine 1% 8x/day, topical ganciclovir gel)
4) oral antiviral therapy (acyclovir, valacyclovir)
What is the most common cause of infectious corneal blindness in the US?
HSV stromal keratitis
What is herpetic interstitial stromal keratitis?
unifocal or multifocal haze or whitening of hte stroma in the absence of epi defect
What is a ddx for herpetic interstitial stromal keratitis?
1) VZV keratitis
2) Acanthamoeba keratitis
3) syphilis
4) EBV keratitis
5) mumps keratitis
6) Lyme disease
7) sarcoid
8) Cogan syndrome
Where is the primary source of inflammation in herpetic disciform keratitis?
The endothelium (although stromal and epithelial edema are the more visible signs on exam)
Is there active viral replication in HSV stromal keratitis?
No, HSV stromal keratitis is thought to be primarily inflammatory
Is a treatment dose or prophylactic dose of antiviral drug used with HSV stromal keratitis?
A prophylactic dose (e.g., trifluridine qid, acyclovir 400 bid, or valacyclovir 500 daily)
Can herpetic infection lead to neurotrophic keratopathy?
Yes
What is the common appearance of a neurotropic ulcer?
rolled edges with gray, elevated appearance
What percent of all cases of zoster involve V1?
15%
What percent of cases of zoster involving Vq have ocular involvement?
70%
How do the pseudodendrites of herpes zoster differ from the true dendrites of HSV epithelial keratitis?
1) lack of central ulceration
2) minimal staining with fluorescein or rose bengal
3) blunt ends rather than bulbous
What are the two forms of epithelial keratitis seen in HZO?
1) punctate epithelial keratitis
2) dendritic epithelial keratitis
What percent of patients with ocular manifestations of zoster develop diminished corneal sensation?
50%
What are the current treatment options for HZO antiviral therapy?
1) famciclovir 500mg PO tid
2) valacyclovir 1g PO tid
3) acyclovir 800mg PO 5x/day
all 7-10 days, ideally started within 72 hours of onset of skin lesions
Can amitriptyline reduce the duration of postherpetic neuralgia if given early in the course of HZO?
yes
What are the three forms of EBV keratitis?
1) subepithelial
2) anterior to midstroma ring-shaped opacities
3) deep or full-thickness infiltrates
What is the impact of antiviral therapy on the corneal manifestations of EBV infection?
Unknown at present
How can a diagnosis of CMV keratitis be confirmed?
PCR testing of aqueous obtained by AC tap during active disease. One may consider simultaneous serum testing to distinguish between systemic and local disease.
Is CMV keratitis responsive to famciclovir, acyclovir, or its derivatives?
No. However, it is responsive to ganciclovir. and valganciclovir.
What are the 3 classic clinical patterns associated with adenoviral eye infection?
1) simple follicular conjunctivitis (multiple serotypes)
2) pharyngoconjunctival fever (serotypes 3 or 7)
3) epidemic keratoconjunctivitis or EKC (serotypes 8, 19, 37, subgroup D)
Which of the adenoviral eye diseases has significant corneal involvement?
Epidemic keratoconjunctivitis (EKC)
What are the common findings of EKC?
1) follicular conjunctiviis with pseudomembranes or true membranes and petechial hemorrhages
2) corneal erosions
3) punctate epithelial keratitis (due to adenoviral replication in the epithelium)
For how long after the onset of symptoms in EKC does viral shedding typically occur?
10-14 days
To which virus family does molluscum contagiosum belong?
The poxviridae
What are the common clinical features of molluscum contagiosum infection?
1) follicular conjunctivitis
2) PEK
3) Smooth nodule with umbilicated central core
How can molluscum contagiosum lesions be managed?
1) excision
2) cryotherapy
3) incision of central portion of the lesion
Which serotypes of HPV are associated with malignant transformation?
16 and 18
Which viruses cause Acute Hemorrhagic Conjunctivitis (AHC)?
1) Enterovirus type 70
2) Coxsackievirus A24
3) Adenovirus type 11
What are the clinical features of Acute Hemorrhagic Conjunctivitis (AHC)?
1) petechial hemorrhages of bulbar and tarsal conj
2) eyelid edema
3) chemosis
4) PEK
5) Preauricular adenopathy
What is Demodex?
a genus of mites whose presence can be suggested by waxy “sleeves” around eyelashes extending from the eyelid margin
Are conjunctival membranes typically seen in H. influenzae conjunctivitis?
No
Do most cases of bacterial conjunctivitis resolve without treatment?
Yes, within 2-7 days.
Is gonococcal conjunctivitis generally indolent or rapidly progressive?
rapidly progressive
What is the recommended therapy for a non-penicillin-allergic patient with gonococcal conjunctivitis?
If no corneal ulcer: 1g ceftriaxone IM x 1
If corneal ulcer: 1g ceftriaxone IV q12h x 3 days
May consider oral therapy for possibility of concomitant chlamydial infection as well
In order of prevalence, which microbes are the most common causes of neonatal bacterial conjunctivitis?
1) Chlamydia trachomatis
2) Strep viridans
3) Staph aureus
4) H. influenzae
5) Group D Strep
6) M. catarrhalis
7) E coli
8) N gonorrhoeae
What is first-line therapy for non-disseminated neonatal gonococcal conjunctivitis?
IM or IV ceftriaxone 25-50mg/kg x 1
What is first-line therapy for neonatal chlamydial conjunctivitis?
Erythromycin 12.5mg/kg PO or IV qid x 14 days
What are the 3 primary forms of Chlamydial conjunctivitis?
1) trachoma (A-C)
2) adult and neonatal inclusion conjunctivitis (D-K)
3) lymphogranuloma venereum (L1, L2, L3)
What are the clinical features of trachoma?
1) severe follicular reactino, particularly involving the superior tarsal conjunctiva
2) (late) linear scarring of the superior tarsal conjunctiva (Arlt line)
3) Herbert pits (limbal depressions resulting from involution and necrosis of follicles)
4) epithelial keratitis and superficial fibrovascular pannus
What clinical features are required for diagnosis of trachoma?
At least 2 of the following:
1) conjunctival follicles on superior tarsal conjunctiva
2) limbal follicles and Herbert pits
3) typical tarsal conjunctival scarring (Arlt line)
4) vascular pannus, particularly at superior limbus
What is first-line therapy for active trachoma?
1) tetracycline 1% ophthalmic ointment bid x 2 months
2) azithromycin 1g PO x 1 dose
What is the quickest treatment for adult chlamydial conjunctivitis?
azithromycin 1g PO x 1 dose
What is Parinaud oculoglandular syndrome?
A granulomatous conjjunctivitis associated with regional lymphadenopathy, most often caused by Cat-scratch disease, which in turn is most often caused by Bartonella henselae.
What is the classic conjunctival manifestation of Parinaud oculoglandular syndrome?
Gelatinous, hyperemic, granulomatous lesions of conjunctiva developing 3-10 days after inoculation.
What is the relative risk of corneal infection in contact lens wearers vs. non-contact lens wearers?
10x
What is the most common bacterial pathogen in contact-lens related keratitis?
Pseudomonas aeruginosa
What percent of patients with culture-proven microbial keratitis are contact lens wearers?
19%-42%
Is the epithelial demarcation of corneal ulcers usually sharp or indistinct?
Epithelial border sharp. Stromal border indistinct.
Infectious crystalline keratopathy is usually associated with which types of organisms?
alpha-hemolytic Strep species
Infectious keratitis may occur with an intact epithelium due to which kinds of organisms?
slow-growing, fastidious organisms such as mycobacteria and anaerobes
Which organisms are most commonly seen in bacterial keratitis (of all causes)?
1) Staph aureus
2) Staph epidermidis
3) Strep pneumoniae
4) Pseudomonas aeruginosa
5) Enterobacteraciae
Initial cultures are recommended for corneal infiltrates with what characteristics?
1) extension into central cornea
2) extension into deep stroma
3) large area (> 2mm)
4) history or clinical features concerning for fungal, amoebic, mycobacterial or resistant organisms
Do 3rd and 4th generation fluoroquinolones have significant activity against MRSA?
No, they have limited activity against MRSA.
What are indications that an infectious keratitis is responding to antimicrobial therapy?
1) blunting of perimeter of stromal infiltrate
2) decreased density of stormal infiltrate
3) reduction of stromal edema
4) reduction in AC inflammation
5) re-epithelialization
6) cessation of corneal thinning
Which conditions should be met to consider instituting steroids in a patient with a presumed bacterial keratitis?
1) appropriate antibiotic therapy should be initiated
2) patient must be able to return for frequent follow-up examinations
3) no additional infectious organisms (superinfections) are suspected
Atypical mycobacterial infections have been identified in patients status post which type of refractive surgery?
LASIK
What percent of infectious keratitis is due to fungal infection?
5-10%
What are classic risk factors for fungal keratitis?
1) trauma to the cornea with vegetation
2) contact lens wear
3) topical corticosteroid use