1. Corneal Diseases-Revision
Ayesha S. Abdullah

2. 1 2 3 4
Corneoscleral Limbus

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

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

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

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

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

8. 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

9. 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

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

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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

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

21. 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

22. 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

23. 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

24. 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

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

26. Most Likely Diagnosis
FUNGAL

27. 2 Most likely differential diagnoses
Corneal Ulcer
Uveitis
Endophthalmitis

28. Signs?

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

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

31. Findings?
Denritic ulcer

32. 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

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

34. Diagnosis?
Acanthamoeba Keratitis

35. Most Likely Diagnosis
Vitamin A Deficiency

36. Diagnosis
Phlyectenular conjunctivitis
Phlyctenulosis

37. Diagnosis?
Scelritis

38. Diagnosis?
Episcleritis

39. Signs?
Corneal prosthesis in a case of failed keratoplasty