6.1.5. Recognises common ocular abnormalities and refers when appropriate. Flashcards
What’s the benefits of using OCT?
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3D structure
Retina, vitreous & optic nerve head
High resolution ~5µm Axial / ~15µm Transverse
Anterior eye & choroid also possible -
Quantifiable measures
Intra-retinal layer thicknesses & volumes
ONH parameters & manual callipers. Scleral lenses 200um, Disc size changes for glaucoma, Melanoma changes in choroid, Oedema for DR -
Statistical analysis
Normative values & progression - No need for pupil dilation in many people
Where is OCT indicated?
-
Suspected maculopathy
- Distortion on amsler
- AMD (standard in hospitals)
- Diabetes
- Macula detachments, holes, swelling, etc.
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Glaucoma
- RNFL thickness
- Optic disc
- Macula thickness
- Choroidal Melanoma
- Drusen Vs Exudates
- ERMs
- CRVO
What principle does OCT work upon?
Light interferometry
Depth at which light is reflected within the sample is measured. Splitter splits beam of light. One arm of the light is reflected from a mirror & the other from the retina. They then recombine to undergo interference, allowing depth & reflectivity measurement.
A scan - represents depth & reflectivity of a point in the scan
B scan - combines multiple A scans to form a cross sectional image (what we normally see!)
C scan - combines multiple B scans to form a 3D image. Looks cool but has little value except to impress the px!v
Types of Retinal Oedema & Common Associated Conditions
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3 Types
1. Diffuse retinal thickening (thick & loss of regularity)
2. Cystoid oedema (dark black pockets)
3. Sub retinal fluid (between RPE & neural retina) -
Commonly Associated Conditions
- Wet AMD
- Diabetic maculopathy
- CSR
- Secondary to cataract/ocular surgery
Drusen Vs Hard Exudates
Drusen are formed between Bruch’s membrane and the retinal pigmented epithelium
Hard exudates form within the retina predominantly at the level of the outer plexiform layer
Exudates normally by area of oedema - therefore if you see exudates, suspect oedema!
Types of PEDs & Common Associated Conditions
Lid lesions (signs of malignancy)
- Bleeding
- Asymmetrical shape
- Change in colour
- Ulceration, irregularity, telangiectasia, pearly appearance, and loss of eyelid margin architecture (notching)
- Diplopia or Proptosis indicating orbital invasion!
Cataract technique
- Retroillumination of the lens
- Optic section of the lens
Glaucoma or Glaucoma suspects technique
- Vertical elongation of cup
- Thinking of ISNT - may do OCT to double check
- Disc haems
Chalazion
- Descript - Sterile inflammation of meibomian gland (cyst) causing stagnation of secretion from the gland, leading to a more chronic lesion. Can follow an internal hordeolum
- Cause - May occur spontaneously or follow an acute hordeolum (internal), chronic bleph
- Sxs - painless lid lump, rarely induced astigmatism
- Management - warm compress & massage. Steroid or excision
Hordeolum
- Descipt - Either external (stye-acute bacterial infection of eyelash glands) or internal (meibomian gland)
- Causes - chronic bleph
- Sxs - tenderness, pain if internal sometimes, watering
- Management - warm compress & massage, if mucous discharge then antibiotic treatment using chloramphenicol
Trichiasis
- Descript - misdirected lashes
- Causes - chronic blepharitis, infection like herpes zoster, surgery, trauma
- Management - removal, laser ablation
Distichiasis
- Descript - growth of abnormal number of lashes
- Causes - intense chronic inflammation like steven johnsons, or OCP. Can be congenital!
- Management - removal, ablation, cryotherapy
Sqamous cell papilloma
- Descript - benign epithelial tumour, skin-tag & wart like
- Causes - human papilloma virus
- Management - normally goes by itself, excision, cryotherapy & laser or chemical ablation
Serborrhoeic Keratosis (basal cell papilloma)
- Descript - light- to dark-brown plaque with a friable, greasy, verrucous surface and a ‘stuck-on’ appearance
- Causes - elderly, common, numerous
- Management - shave biopsy, excision, laser, cryotherapy
Actinic Keratosis
- Descript - hyperkeratotic plaque with distinct borders and a scaly surface that may become fissure, sandpaper like, possible malignancy
- Causes - elderly, UV, white
- Management - routine referral, excision, cryotherapy
Melanocytic naevus
- Descript - can be congenital (kissing naevus possible), compound naevus (rasied & scaly), junctional naevus (uniform & brown), intradermal naevus (most common, no malignancy potential)
- Management - complete excision if suspect melanoma
Molluscum Contagiosum
- Descript - viral infection; caused by poxvirus, very young or adults immuno compromised
- Causes - linked with AIDs, eczema, swimming pools
- Sxs - Skin nodule(s) (typically 2-3 mm diam), often with a central depression (‘umbilicated’), Can cause conjunctivitis - follicles, redness, watering, photophobia, epitheliopathy etc
- White cheesy material can be discharged
- Management - self-limiting (goes after few weeks or months), referral if no resolve for excision
Basal cell carcinoma
- Risk Factors - Old, White, UV exposure
- Types:
- Nodular - pearl like, few dilated vessels
- Nodulo-ulcerative - centre ulcerated, pearly rolled edges, telangiectasia
- Sclerosing - looks clear, margins hard to define. Don’t mistake for blepharitis!
- Management - needs referral (soon) for biopsy
Squamous cell carcinoma
- Risk Factors - Old, White, UV exposure, Immunocompromised
- Types:
- Nodular - hyperkeratotic with crusting, erosions, fissures
- Ulcerating - red base, defined “hard looking” borders with a slight crusty look
- Cutaneous horn
- Management - needs referral (urgent within a week) for biopsy
Other eyelid cysts:
- Cyst of Zeiss - cyst of anterior lid margin
- Cyst of Moll - retention cyst near canthus
- Sebaceous cyst
- Epidermal inclusion cyst - implantation of epidermis into dermis following trauma or surgery, round, firm & whitish-yellowish looking due to keratin
- Dermoid cyst
- Xanthelasma
Ectropian
- Outward rotation of lid margin
- TESTS:
- Distraction test
- if lower lid can be pulled >6mm from globe, it is lax, positive test indicates canthal tendon laxity
- Snap-back test
- with finger, pull lower lid down towards inferior orbital margin
release: lid should snap back
lid slow to return to its normal position: indicates poor orbicularis tone
- with finger, pull lower lid down towards inferior orbital margin
- Types - Involutional (age related causing laxity), Cicatricial (scarring of skin), Paralytic (facial palsy i.e. Bell’s), Mechanical (tumour, lid swelling etc), Congenital (rare bilateral condition)
- Management - less lid rubbing (induces laxity), drops, routine referral if severe
Entropian
- Inward rotation of lid margin
- TESTS:
- Distraction test
- if lower lid can be pulled >6mm from globe, it is lax, positive test indicates canthal tendon laxity
- Snap-back test
- with finger, pull lower lid down towards inferior orbital margin
release: lid should snap back
lid slow to return to its normal position: indicates poor orbicularis tone
- with finger, pull lower lid down towards inferior orbital margin
- Test of Induced Entropion (TIE-2 test)
- ask patient to look down
hold upper lid up as high as possible
ask patient to close the eyes as tightly as possible
The TIE-2 test is positive if this provokes an intermittent lower lid
entropion
- ask patient to look down
- Types - Involutional, Cicatricial (scarring & contraction of palp conj e.g. in chronic bleph), Spastic (random orbicularis contraction e.g. after surgery or blepharospasm), Congenital (rare)
- Management - Lash epilation, Lubrication, routine referral if severe
Keratocanthoma
- Descript - Rare, rapidly growing, keratin filled crater, pink dome
- Causes - white, UV, immunosuppresive therapy
- Management - spotaneous involution after growing for 2-3 months, taking up to a year!! leaving a scar! Excision also works
Conjunctival lesions
- Pinguecula
- UV protection. Lubricants. If inflammed, steroids. Referral if vision affected or cosmetically unacceptable
- Pterygium
- UV protection. Lubricants. If inflammed, steroids. Referral if vision affected or cosmetically unacceptable or astigmatism induced
- Retention cyst
- Goes by itself, or punctured with a needle using a topical anaesthetic
- Conjunctivochalasis
- Lubrication & treat chronic bleph. Conjunctival resection (cutting out tissue) if severe.
- Concretions
- Lubrication. Removed using needle under topical anaesthesia.
AMD & Macular abnormalities
- PED
- If drusenoid, then regular AMD management
- If serous or fibrous with signs of AMD, then most likely urgent within 1-2 weeks as suspect wet AMD
- Macula hole
- If Lameller hole & not causing trouble with vision or too much distortion, then worth monitoring over next 6 months whilst giving amsler
- ERM
- Monitor, 1 yr recall
- If VMT, then separate management as may progress to macula hole so might require referral within 3-4 weeks if vision worse than 6/7.5
- CSR
- Routinely referred soon 3-4 weeks
- Some HES will only want to see CSR if chronic for at least 4 months because normally it will resolve itself in 6 or so weeks. Photodynamic laser
- Oedema
- Referred urgently within 2 weeks e.g. proliferative DR, CRVO, after cataract surgery
Retinitis Pigmentosa
- Descript - inherited diffuse retinal degenerative disease affecting rods then cones
- Cause - genes
- Signs - Dark adaptation trouble, VF loss, Bone-spicules, Narrower A/V, Disc pallor, Possible maculopathy
- Management - Genetic counselling, LVAs & adaptations like expanding FOV
Congenital anomalies of the Optic Disc
Without systemic associations:
- Tilted disc
- Disc drusen
- Optic disc pit
- Myelinated nerve fibres
Congenital anomalies of the Optic Disc
With systemic associations:
- Coloboma
- Morning glory
- Hypoplasia
- Megalopapilla
- Peripapillary staphyloma
- Dysplasia
Iris Melanoma
- Descript - pigmented area of iris, normally inferior
- Causes - UV, white
- Signs & Sxs - pupil distortion, causes cataracts & uveitis, raised, has surface vessels (DD from iris naevus), 3-5mm
- Management - take a photo & refer routinely for iridectomy. If angle invaded, iridocylotomy. Radiotherapy
Fuch’s Dystrophy
- Descript - bilateral endothelial loss, >women
- Causes - inherited, middle age onset
- Signs - blurring more in morning due to oedema, corneal guttata, beaten bronze appearance
Choroidal Naevus Vs Melanoma
- C - Close to ON
- O - Orange pigment lipofuscin
- N - No drusen
- S - Symptoms (F+F, visual disturbance if raised)
- T - Thickness (>2mm)
- A - Absence of halo (ring of pallor)
- N - New
- T - Too big (>5mm)
CHRPE
common benign lesion, usually congenital. Can be single or grouped (bear tracks) Linked to FAP (familial adenomatous polyposis) (liver condition) if 4 or more CHRPEs that are separated more than bear tracks are detected.
- Low malignancy risk so just monitor
Macula scan: raster cube scan
50% total RGCs at macula
GCC (ganglion cell complex i.e. innermost 5 layers, ILM, RNFL, GCL, IPL, INL)
GChart only measures thickness of GCC i.e. NRR, not things like disc swelling
Peripheral macular thickness asymmetry can occur in healthy eyes, but central macular thickness is highly symmetrical
Retinal nerve fibre layer: circumpapillary scan
- Provides thickness measurements of RNFL
- Produces a RNFL thickness map beginning and ending nasally, with superior, temporal and nasal quadrants in between
- Thickness compared to normative data base, plotted on a probability graph depicting 95%, 5% and 1% confidence limits
- The greater amount of nerve fibre layers coming from superior and inferior sections of the disc is highlighted by the double hump of RNFL thickening at those poles (absence of double hint = indicates nerve fibre loss in these areas
Macular hole
Routine referral to ophthalmology if full thickness / VA drop
Vitrectomy which can help to close hole with some slow recovery to normal VA
ERM & wrinkling of retinal surface
Routine referral if symptomatic / px wants surgery
Vitrectomy & membrane peel
