Cornea (Alex's quizlet)

t or f: the epithelium is able to regenerate

true

t or f: the stroma is able to regenerate

false

what is the average corneal thickness?

540 um

hallmark findings for punctate epithelial erosions (PEEs)

areas of epithelial loss that stain with fluorescein

superior PEEs are associated with which conditions?

SLK, VKC, floppy eyelid syndrome

inferior PEEs are associated with which conditions?

exposure keratopathy, chronic blepharitis

interpalpebral PEEs are associated with which conditions?

dry eye

diffuse PEEs are associated with which conditions?

HSK, HZO

central PEEs are associated with which conditions?

contact lens wear

hallmark findings for punctate epithelial keratitis (PEK)

areas of swollen epithelial cells that appear grey or opalescent

stain with Lissamine Green, variable staining with fluorescence

hallmark findings for superficial punctate keratitis (SPK)

areas of epithelial loss similar to PEE

stain with fluorescence

what is the difference between PEEs and SPK?

look the same under SLE

SPK is associated with inflammation, while PEEs are not

hallmark findings for subepithelial infiltrates

non-staining inflammatory cells that are below the epithelium

appear grey with indistinct margins

associated with sectoral redness

PEK is associated with which conditions?

Thygeson superficial punctate keratitis, viral infections

subepithelial infiltrates are associated with which conditions?

marginal keratitis, HZO, EKC, contact lens overwear

hallmark findings for deep infiltrates

non-staining inflammatory cells, cellular debris & tissue necrosis located in the anterior stroma

appear grey to white with indistinct margins

associated with larger area of conj hyperemia

deep infiltrates are associated with which conditions?

PUK, microbial keratitis, HSK

hallmark findings for ulceration

a deep infiltrate with overlaying staining and tissue loss

in order to be called an ulcer, what must be present?

deep infiltrate

ulcerations are associated with which conditions?

microbial keratitis, PUK

hallmark findings for corneal melting

epithelial defect with stromal loss

precursor to corneal perforation

corneal melting is associated with which conditions?

severe corneal infections, prolong topical NSAID use

hallmark findings for descemetocele

protrusion of Descemet membrane into anterior layer of the cornea

seen with severe corneal ulceration

descemetocele is associated with which conditions?

severe corneal infections

hallmark findings for epithelial edema

swelling of the epithelium seen as cyst

will be seen when the endothelium is compromised

epithelial edema is associated with which conditions?

Fuch's endothelial dystrophy

hallmark findings of corneal neovascularization

blood vessel growth into the cornea at the limbus

corneal neovascularization is associated with which conditions?

contact lens overwear, blepharitis

hallmark findings of pannus

blood vessel growth into the cornea with overlaying scar tissue

pannus is associated with which conditions?

chronic inflammation

hallmark findings for folds in Descemet's membrane

dark crisscross lines that appear in deep corneal layers

will have corneal edema

folds in Descemet's is associated with which conditions?

post-cataract surgery

*usually self-limiting

hallmark findings for breaks in Descemet's membrane

deep linear opacities that run vertically

breaks in Descemet's membrane is associated with which conditions?

hydrops associated with keratoconus

infantile glaucoma

traumatic birth

common etiologies for bacterial keratitis

Staph spp, Pseudomonas aeruginosa

common etiologies for fungal keratitis

Fusarium spp, Candida spp, Aspergillus

common etiologies for viral keratitis

herpes simplex-1, Varicella zoster

t or f: microbial keratitis is most commonly viral

false, bacterial is most common

risk factors for bacterial keratitis

CL wear (especially if non-compliant), topical steroid use, ocular surface disease, ocular trauma, previous infection

clinical findings for bacterial keratitis

deep corneal infiltrates

epithelial defect over the infiltrate and typically the size of the infiltrate

diffuse conj hyperemia

cells & flare in ant chamber

complications of bacterial keratitis

corneal scarring, irregular astigmatism, corneal neovascularization, corneal perforation

Tx for bacterial keratitis

topical antibiotic solution/ointment (broad spectrum is used until cultures are returned)

topical cycloplegics (pain control & prevent post synechia formation)

topical steroids after 2-3 days of improvement (re-epithelialization)

oral antibiotics for gonococcal

Is Candida a yeast or filamentous fungi?

yeast

Is Fusarium a yeast or filamentous fungi?

filamentous

Is Aspergillus a yeast or filamentous fungi?

filamentous

risk factors for fungal keratitis

ocular surface disease, long term topical steroid use, trauma with vegatative matter, CL wear, immunocompromised

clinical findings for yeast fungal keratitis

conj hyperemia

endothelial plaques (collection of inflamm/immune cells)

hypopyon in ant chamber

round "button" infiltrate

**NO feathery borders or satellite lesions

complications for yeast fungal keratitis

corneal scarring, corneal perforation, endophthalmitis

Tx for yeast fungal keratitis

debridement, topical antifungal drop, topical antibiotic

clinical findings for filamentous fungal keratitis

conj hyperemia

endothelial plaques (collection of inflamm/immune cells)

hypopyon in ant chamber

feathery ulcer border

satellite lesions

complications of filamentous fungal keratitis

corneal scarring, corneal perforation, endophthalmitis

Tx for filamentous fungal keratitis

debridement, topical antifungal drop, topical antibiotic

what are the 2 life stages of Acanthamoeba keratitis?

trophozoite- active, reproducing

cyst- dormant, resistant

risk factors for Acanthamoeba keratitis

CL wear with water exposure

clinical findings of Acanthamoeba keratitis (early, intermediate, and late stages)

pain that does not match SLE findings (reported pain is worse than expected)

cells & flare in ant chamber

conj hyperemia

early: PEEs, diffuse microcystic epithelial changes, pseudodendrites

intermediate: radial perineuritis, multifocal stromal infiltrates

late: ring infiltrate

complications from Acanthamoeba keratitis

scleritis, hypopyon, corneal scarring/melting, secondary glaucoma, retinal inflammation

Tx for Acanthamoeba keratitis

refer out

topical antimicrobials (pool cleaners- PHMB, Chlorhexidine, Brolene)

t or f: dendritic keratitis has live virus replication

true

clinical findings for dendritic (epithelial) herpes keratitis

day 1-3: swollen epithelial cells in a punctate or stellate pattern

day 4: dendritic epithelial lesion

follicular conjunctivitis

cells & flare

reduced corneal sensitivity

elevated IOP (from trabeculitis)

possible eyelid vesicles

complications of dendritic (epithelial) herpes keratitis

corneal scarring, geographic ulcer, neurotrophic keratitis

Tx for dendritic (epithelial) herpes keratitis

topical antiviral drop or gel

oral antiviral medication (cheaper than topical)

topical cycloplegic

topical steroid (after epithelium heals)

what is a geographic ulcer?

enlargement of the dendritic ulcer after the use of topical steroids

what is neurotrophic keratitis (or keratopathy)?

cornea loses trigeminal nerve innervation

there is no stimulus of pain/feeling and no signal to re-epithelialize after injury

which conditions can have neurotropic keratitis?

dendritic (epithelial) herpes keratitis, herpes zoster, ocular surface disease, diabetes, topical medication toxicity

describe the 3 stages of neurotrophic keratitis

1- epithelial irregularities and PEEs

2- persistent epithelial defects with stromal involvement

3- corneal ulceration with stromal melting (EMERGENCY)

complications of neurotrophic keratitis

corneal perforation (EMERGENCY)

Tx for stage 1 neurotrophic keratitis

preservative-free AT

autologous serum

punctal occlusion

moisture chamber goggles

Tx for stage 2 neurotrophic keratitis

cenegermin (Oxervate)- contains human growth factor

amniotic membrane

scleral or bandage CL

tarsorrhaphy (join upper & lower lids)

Tx for stage 3 neurotrophic keratitis

amniotic membrane

advanced corneal surgery

what are the 2 types of stromal herpes simplex keratitis?

immune (interstitial) & necrotizing

t or f: immune stromal herpes simplex keratitis has live virus

false

t or f: necrotizing herpes simplex keratitis has live virus

true

which is more aggressive: immune or necrotizing stromal herpes keratitis?

necrotizing

clinical findings for immune (interstitial) stromal herpes simplex keratitis

deep stromal infiltrates

intact epi & endo

cells & flare

increased IOP

complications from immune stromal herpes simplex keratitis

corneal neovas, corneal scarring

clinical findings for necrotizing stromal herpes simplex keratitis

deep stromal infiltrate

epithelial defect

significant cells & flare with hypopon developement

increased IOP

thinning of cornea

Tx for immune stromal HSK

**prescribe all at the same time

topical steroid drop

oral antiviral

topical cycloplegic

Tx for necrotizing stromal HSK

**prescribe all at the same time

topical antiviral

oral antiviral

topical cycloplegic

if perforation: penetrating keratoplasty

t or f: there is live virus with herpes simplex endotheliitis (disciform) keratitis

false

clinical findings for disciform keratitis

intact epi

disc-shaped stromal edema (from endotheliiitis)

Wessely ring (circular, immune-mediated stromal infiltrate)

granulomatous cells & flare

elevated IOP

t or f: stromal defects stain with fluorescence

if the epithelium is intact, then no

if epithelium is not intact, then maybe

complications of disciform keratitis

corneal scarring, corneal neovas, secondary glaucoma

Tx for disciform keratitis

topical steroid + oral/topical antiviral + topical cycloplegic

etiology of herpes zoster ophthalmicus

Varicella zoster (virus)

demographics of herpes zoster ophthalmicus

70-80 years old

immunocompromised

Hx of chicken pox

what are the 5 phases of herpes zoster ophthalmicus?

1. prodromal phase

2. maculopapular rash

3. epithelial keratitis

4. nummular keratitis

5. stromal (interstitial) keratitis

hallmark findings for prodromal phase of HZO (including timing)

3-5 days before appearance of the rash

can mimic upper respiratory infection

tiredness, malaise, fatigue

dermatome has tingling, itching, or burning sensation

hallmark findings for maculopapular rash phase of HZO (including timing)

vesicles appear 24 hrs after onset of symptoms

respect midline

eyelid edema

Hutchinson sign

hallmark findings for epithelial keratitis of HZO (including timing)

2-3 days after rash appears

spontaneously resolves

pseudodentrite appearance (no staining on terminal bulbs)

t or f: herpes zoster has live virus

there is NO live virus on the cornea

there is live virus on the skin

hallmark findings for nummular keratitis of HZO (including timing)

occurs 10 days after rash appears

develops at site of pseudodendrites

appear as subepithelial granular deposits with stromal haze

hallmark findings for stromal (interstitial) keratitis of HZO (including timing)

occurs 3 weeks after rash appears

deep infiltrates with intact epithelium & endothelium

how does HZO affect the conj & sclera?

conjunctivitis with follicles & pseudomembranes/membranes

episcleritis

complications from HZO

mucus plaques, neurotropic keratitis, post-herpetic neuralgia

Tx for HZO maculopapular rash

oral antiviral

topical antibiotic ointment (use when rash begins to crust over)

Tx for HZO epithelial keratitis

artificial tears

spontaneously resolves

Tx for HZO nummular/stromal/disciform keratitis

topical steroid

Tx for HZO mucus plaques

topical steroid

Tx for neurotropic keratitis/keratopathy

artificial tears

bandage CL

amniotic membrane

Cenegermin (Oxalate)

why is it important to treat HZO as quickly as possible?

reduce risk of developing post-herpetic neuralgia