Corneal Diseases-Revision Ayesha S. Abdullah 20.04.2017

1 2 3 4 Corneoscleral Limbus

What is the horizontal diameter of an adult cornea ? 8.7 9.7 10.7 11.7 12.7 Verticle-------10.6 mm Horizontal---11.7 mm Thickness Central portion----0.52 mm Peripheral portion----1 mm

Horizontal Corneal diameter is most likely to change in which of the following conditions? Microcornea Keratoconus Corneal Dystrophy Corneal Ectasia Post-refractive surgery

The central corneal thickness of an adult cornea is about 400 micron 500 micron 600 micron 700 micron 800 micron

Which of the following structures of the cornea is least innervated? Epithelium Bowman’s layer Stroma Limbus Endothelium Which is the most innervated?

The epithelial cell are shed every Week Fortnightly Month 3 months Never What is the significance of this fact?

Which of the following corneal injuries is most likely to heal as corneal opacity? Injury to epithelial Wing cell layer Injury to epithelial Basal cell layer Injury to epithelial Basement membrane Injury to Bowman’ s membrane Injury to stroma

Epithelium, Bowman’s layer, Stroma, Descemet’s Membrane, Endothelium Match the Function with the Layer Epithelium, Bowman’s layer, Stroma, Descemet’s Membrane, Endothelium 1. Assists in healing of corneal ulcers 2. Barrier to aqueous solutions 3. Keeps cornea dehydrated 4. Main refractive component 5. Maintains healthy endothelium 6. Tough layer maintains shape of the cornea

Which of the following parts of the cornea is least vascular? Corneal Limbus Central Cornea Deep Cornea Peripheral Cornea Superficial Cornea Ans. B

Which of the following cranial nerves is responsible for corneal sensations? 3rd 4th 5th 6th 7th Ans C Frontal, Nasociliary, Lacrimal – it is nasociliary

Which of the following facts is most responsible for the transparency of cornea Absence of blood vessels Endothelial pump mechanism Regular structure of stroma Scarcity of cell nuclei in stroma Tight junctions of the epithelial cells

Which of the following statements relate best to punctate corneal erosions? A. Stain well with Rose Bangal Are a specific sign for corneal dystrophy Stain poorly with fluorescein Heal as corneal opacity Are extremely painful

Which of the following statements relates best to Superficial Punctate epithelial keratitis? It is pathognomonic of fungal corneal infections It is shed epithelial cells Stains well with Fluorescein Stains with rose bengal Heals poorly with corneal scars

A 65 year old male who underwent cataract developed significant corneal oedema. Which of the following could be the most likely cause? Endothelial decompensation Chronic elevation of IOP Epithelial loss Corneal stromal injury Toxic reaction to irrigation fluids during surgery

A 45 year old lady presented with watering of the eye A 45 year old lady presented with watering of the eye. On examination she had corneal filaments. Which of the following is the most likely diagnosis? Corneal ulcer Conjunctivitis Dry eyes Blepharitis Meibomian Gland Dysfunction Small coma shaped mucus strands One end attached with epithelium

Corneal Panus is most suggestive of which of the following pathological process? Acute infection Allergy Chronic inflammation Chronic infection Carcinogenesis Inflammatory or degenerative ingrowth of fibro vascular tissue from limbus

Which of the following pathogens can produce corneal infection in intact epithelium? Haemophilus Pseudomonas Staphylococcus Streptococcus Mycobacterium 1.Neisseria gonorrhoeae 2.Corynebacterium diphtheriae 3.Listeria 4.Haemophilus

Which of the following refractive state is most likely to be seen in a case of keratoconus? Hypermetropia Simple Myopia Pathological Myopia Astigmatism Irregular Astigmatism

What organism is most commonly cultured from corneal foreign bodies after wooden trauma? Pseudomonas Staphylococcus Neisseria Sporothrix Aspergilus

A 35 year old patient presents with corneal ulcer A 35 year old patient presents with corneal ulcer. Outline the treatment for this patient. Topical antibiotics – combination therapy with fortified amino glycoside and fortified cephalosporin or monotherapy with fluoroquinolone. Initial instillation at hourly intervals. Cycloplegic eye drops Oral or injectable NSAIDs for pain relief IOP lowering medications if the IOP rises

Missing some important risk factor A 60 year old patient presented with corneal ulcer and was provided maximum treatment. He did not respond to treatment. List four important causes for the poor response to treatment. Wrong diagnosis Wrong treatment Drug toxicity Missing some important risk factor

Match the sign with the type of corneal ulcer A) Viral, B) Fungal, C) Staphylococcal, D) Pseudomonas, E) Acanthamoeba 1. Oval, yellow-white, densely opaque stromal suppuration surrounded by relatively clear cornea 2. Thick mucopurulent exudate, diffuse liquefactive necrosis and semi-opaque ground glass appearance of adjacent stroma 3. Greyish-white ulcer with indistinct margins Surrounded by feathery infiltrates 4. Blurred vision and disproportionate pain Patchy anterior stromal infiltrates, Perineural infiltrates 5. Branching lesion with reduced corneal sensitivity

List three most likely differential diagnoses for a patient presenting with dendritic corneal ulcer. Herpes zoster keratitis Healing corneal abrasion Pseudodendrites due to soft contact lens Drug toxicity Name any three topical medications used for the specific treatment of viral corneal ulcer. Acycloguanosine Trifluorothymidine Adenine arabinoside Idoxuridine

Three most likely DDx Pneumococcus Keratitis Pseudomonas Keratitis Gonococcus Keratitis Fungal Keratitis

Most Likely Diagnosis FUNGAL

2 Most likely differential diagnoses Corneal Ulcer Uveitis Endophthalmitis

Signs?

Treatment? Natamycin, econazole with some broad spectrum antibiotic eye drops, cycloplegics and oral NSAIDs need to be prescribed.

What immediate Lab investigations would you request for this patient to arrive at a diagnosis? Gram, Giemsa, Wetmount KOH preparation of corneal scrapping

Findings? Denritic ulcer

Treatment Antiviral therapy Acycloguanosine 3% ointment Trifluorothymidine 1% drops Adenine arabinoside 3% ointment, 0.1% drops Idoxuridine Cycloplegics NSAIDs Name any 3 ocular complications that this patient can develop. (any 3 of these) Conjunctivitis, episcleritis, scleritis, anterior uveitis, optic neuritis, cranial nerve palsies, neurotrophic keratopathy

Exposure keratitis is associated with the paralysis of which of the following cranial nerves?   3rd 4th 5th 6th 7th

Diagnosis? Acanthamoeba Keratitis

Most Likely Diagnosis Vitamin A Deficiency

Diagnosis Phlyectenular conjunctivitis Phlyctenulosis

Diagnosis? Scelritis

Diagnosis? Episcleritis

Signs? Corneal prosthesis in a case of failed keratoplasty