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Toronto Notes 2019 Cornea
Treatment
• sameascornealabrasionuntilre-epithelializationoccurs
• topicalhypertonicsalineointmentatbedtimefor6-12mo,topicallubrication
• bandagecontactlens,anteriorstromalpunctureorphototherapeutickeratectomyforchronic
recurrences
Corneal Ulcer
Etiology
• localnecrosisofcornealtissueduetoinfection
■ infection is usually bacterial; rarely viral, fungal, or protozoan (Acanthamoeba)
• secondarytocornealexposure,abrasion,foreignbody,contactlensuse(50%ofulcers) • alsoassociatedwithconjunctivitis,blepharitis,keratitis,vitaminAdeficiency
Clinical Features
• pain,photophobia,tearing,foreignbodysensation,decreasedVA(ifcentralulcer)
• cornealopacitythatnecrosesandformsanexcavatedulcerwithinfiltrativebase
• overlyingcornealepithelialdefectthatstainswithfluorescein
• maydevelopcornealedema,conjunctivalinjection,anteriorchambercells/flare,hypopyon,corneal
hypoesthesia (in viral keratitis)
• bacterialulcersmayhavepurulentdischarge,viralulcersmayhavewaterydischarge
Complications
• decreasedvision,cornealperforation,iritis,endophthalmitis
Investigations
• Seideltest:fluoresceindroponthecorneaundercobaltbluefilterisusedtodetectleakingpenetrating lesions; any aqueous leakage will dilute the green stain at site of wound
Ophthalmology OP17
Treatment
• urgentreferraltoophthalmology
• culturepriortotreatment
• topicalantibioticseveryhour
• musttreatvigorouslytoavoidcomplications
Table 7. Corneal Abrasion vs. Corneal Ulcer
Crater defect with lymphocytic infiltration
Normal Cornea
Abrasion
Ulcer
Figure 14. Corneal abrasion vs. ulcer
Abrasion vs. Ulcer on Slit-Lamp
An abrasion appears clear while an ulcer is more opaque
Steroid treatment for ocular disorders should only be prescribed and supervised by an ophthalmologist, as they can impair corneal healing, exacerbate herpetic keratitis, and elevate IOP
Time Course History of Trauma Cornea
Iris Detail
Corneal Thickness Extent of Lesion
Abrasion
Acute (instantaneous) Commonly
Clear
Clear
Normal
Limited to epithelium
Ulcer
Subacute (days) Rare
White, necrotic area Obscured
May have crater defect/thinning Extension into stroma
Herpes Simplex Keratitis
• usuallyHSVtype1(90%ofpopulationarecarriers)
• maybetriggeredbystress,fever,sunexposure,andimmunosuppression
Clinical Features
• pain,tearing,foreignbodysensation,redeye,mayhavedecreasedvision,andeyelidedema
• corneal hypoesthesia
• classicformofHSVinfectiousepithelialkeratitisisadendritic(thinandbranching)lesionwith
terminal end bulbs in epithelium that stains with fluorescein
• HSVmaycauseotherformsofinfectiousepithelialkeratitis,aswellasstromalkeratitis(whichmaybe
infectious or immune-mediated), and endotheliitis (presumably immune-mediated but possible role of live virus)
Complications
• cornealscarring(canleadtolossofvision)
• chronicinterstitialkeratitisduetopenetrationofvirusintostroma • secondaryiritis,secondaryglaucoma
Treatment
• topicalantiviralsuchastrifluridine,orsystemicantiviralsuchasacyclovir
• debridementofdendrite
• nosteroidsinitially–mayexacerbatecondition
• ophthalmologistmustexercisecautionifaddingtopicalsteroidsforstromalkeratitis,endotheliitisor
iritis, and patients covered with antiviral prophylaxis
© Julian Kirk-Elleker 2006