Cornea (Infectious and Non-Infectious Keratitis, Ulcers) MCQs

Ophthalmology · 71 free questions with answers & explanations.

1. A 25-year-old contact lens wearer presents with severe eye pain, photophobia, and a ring-shaped stromal infiltrate on slit-lamp examination. Corneal scraping stained with calcofluor white shows double-walled cysts. The most likely causative organism is:
2. A patient presents with a corneal ulcer showing a dendritic (branching) pattern with terminal end bulbs on fluorescein staining. The ulcer has a geographic pattern on further enlargement. What is the most likely causative agent and first-line topical treatment?
3. A farmer presents with a corneal ulcer with a dry, rough surface, satellite lesions, and feathery borders after a twig injury to the eye. Corneal scraping shows septate hyphae. The drug of choice is:
4. A patient with Stevens-Johnson syndrome develops severe dry eyes, symblepharon, and corneal vascularisation. Which layer of the corneal anatomy is most involved in limbal stem cell deficiency contributing to corneal opacification?
5. A 55-year-old patient with rheumatoid arthritis develops a peripheral corneal ulcer with an overhanging edge, thinning, and absent vascularisation progressing circumferentially. This condition is best described as:
6. A 45-year-old patient undergoes LASIK refractive surgery. Three months later she develops a slowly progressive central corneal ectasia with decreasing best-corrected visual acuity. Corneal topography shows inferior steepening. The mechanism of post-LASIK ectasia is:
7. Fuchs' endothelial dystrophy is characterised by primary progressive endothelial cell loss. In the early stage, slit-lamp examination shows:
8. A 20-year-old patient with keratoconus has a contact lens intolerance and best corrected VA of 6/36 with irregular astigmatism. Corneal topography shows inferior steepening with a SimK of 55 D. He is offered corneal collagen cross-linking (CXL). Which of the following is the minimum corneal thickness required for standard (Dresden protocol) CXL?
9. A 50-year-old man with bullous keratopathy secondary to Fuchs' dystrophy undergoes Descemet's membrane endothelial keratoplasty (DMEK). What is the key advantage of DMEK over penetrating keratoplasty (PK) and over DSAEK?
10. A 28-year-old contact lens wearer presents with severe eye pain, photophobia, and a ring-shaped stromal infiltrate with an overlying epithelial defect. Corneal sensation is markedly reduced. Confocal microscopy shows cyst-like double-walled structures. The MOST appropriate initial treatment includes:
11. A patient with a history of cold sores on the lip develops a branching, dendritic corneal ulcer with terminal bulbs on fluorescein staining. The keratocytes show multinucleated giant cells on impression cytology. Herpes simplex stromal keratitis is subsequently diagnosed. Which immunological mechanism is primarily responsible for stromal destruction in HSK?
12. A 35-year-old patient is diagnosed with Fuchs endothelial corneal dystrophy (FECD). Specular microscopy shows endothelial cell count of 950 cells/mm² (normal >2000) with pleomorphism and polymegethism. What is the GOLD STANDARD treatment at this stage when the patient develops significant corneal edema reducing vision to 6/36?
13. A woman presents with bilateral chronic ocular surface disease. Schirmer test I shows 3 mm wetting at 5 minutes. Rose Bengal staining reveals interpalpebral staining. She has rheumatoid arthritis. Which pathophysiological sequence best explains the immune mechanism underlying dry eye in Sjogren syndrome?
14. A contact lens wearer presents with a painful red eye with a ring-shaped stromal infiltrate at the mid-periphery. Corneal confocal microscopy shows highly reflective double-walled cysts. The first-line treatment is:
15. In Fuchs' endothelial corneal dystrophy, the pathological hallmark is accumulation of abnormal extracellular matrix ('guttae') composed primarily of:
16. A 40-year-old farmer presents with a corneal ulcer after injury with a vegetable matter. Slit-lamp examination reveals a gray-white infiltrate with feathery margins, satellite lesions, and an endothelial plaque. Smear with KOH mount shows septate hyphae. The most appropriate initial treatment is:
17. Corneal collagen cross-linking (CXL) for progressive keratoconus uses riboflavin and UV-A light. The Dresden protocol specifies the UV-A irradiance and total energy dose as:
18. In Acanthamoeba keratitis, the pathognomonic slit-lamp finding that distinguishes it from herpes simplex keratitis or fungal keratitis in the early stage is:
19. Fuch's endothelial corneal dystrophy progresses through four stages. The sequence of pathological events in correct order is:
20. Regarding corneal graft survival in penetrating keratoplasty, the 'high-risk' corneal bed is defined by which criteria according to current guidelines, necessitating systemic immunosuppression?
21. In Thygeson's superficial punctate keratopathy, the clinical observation distinguishing it from other causes of SPK (viral, chlamydial, toxic) is:
22. Descemet Membrane Endothelial Keratoplasty (DMEK) has replaced DSAEK as the gold standard endothelial keratoplasty in many centres. The key outcome advantage of DMEK over DSAEK is:
23. Acanthamoeba keratitis classically presents with pain disproportionate to clinical signs and a ring infiltrate. Which stage must be distinguished clinically because it mimics herpetic stromal keratitis?
24. In Fuchs endothelial corneal dystrophy, the primary molecular abnormality involves mutations most commonly in:
25. A patient with active herpes zoster ophthalmicus develops disciform keratitis 3 weeks after the rash. The mechanism underlying this form of stromal keratitis is:
26. The Amsler-Krumeich classification of keratoconus stages is based primarily on which clinical parameters?
27. Thygeson's superficial punctate keratitis (SPK) is characterised by all of the following EXCEPT:
28. In Acanthamoeba keratitis, the clinical feature that most strongly distinguishes it from herpes simplex stromal keratitis is:
29. A patient on long-term topical steroids for keratoconus develops an acute hydrops episode. The mechanism is:
30. Fuchs' endothelial dystrophy follows a pathogenetic sequence. Which of the following correctly describes the earliest histopathological change?
31. A contact lens wearer presents with a painful red eye, ring infiltrate at mid-peripheral cornea, and radial perineuritis (pain with periocular pressure). The most likely diagnosis and first treatment step is:
32. In Fuchs' endothelial corneal dystrophy (FECD), the protein responsible for accelerated endothelial cell apoptosis and guttata formation has been linked to mutations in which gene?
33. Which corneal refractive surgery technique results in a corneal flap created at a stromal depth of approximately 160 microns, with preservation of Bowman's layer entirely?
34. In keratoconus, corneal collagen cross-linking (CXL) with riboflavin and UVA light primarily works by:
35. Acanthamoeba keratitis most commonly presents with pain disproportionate to clinical signs. The pathological basis for this severe pain is:
36. Fuchs' endothelial corneal dystrophy (FECD) shows characteristic 'beaten metal' appearance on specular microscopy. The genetic defect most commonly implicated in late-onset FECD is:
37. Descemet membrane endothelial keratoplasty (DMEK) has largely superseded DSAEK for Fuchs' endothelial dystrophy. The primary advantage of DMEK over DSAEK is:
38. In keratoconus, the Amsler-Krumeich grading system classifies Grade IV keratoconus as:
39. Acanthamoeba keratitis is classically associated with contact lens use. The MOST characteristic early clinical sign that helps distinguish it from fungal or herpes simplex keratitis is:
40. Fuchs' endothelial corneal dystrophy is characterized by bilateral, primary endothelial dysfunction. Which of the following correctly describes the histopathological finding and clinical consequence?
41. Acanthamoeba keratitis is most commonly associated with which risk factor, and which investigation is most specific for diagnosis?
42. Fuchs' endothelial corneal dystrophy (FECD) is characterized by endothelial guttae and progressive endothelial cell loss. The modern surgical treatment that selectively replaces the diseased endothelium is:
43. A 34-year-old rice paddy farmer presents with a rapidly progressive corneal ulcer. Slit lamp shows a 5 mm stromal infiltrate with feathery edges, satellite lesions, and an immune ring (Wessely ring). Confocal microscopy shows linear branching structures. The MOST effective initial treatment is:
44. Fuchs' endothelial corneal dystrophy (FECD) is caused by progressive loss of corneal endothelial cells. The gold-standard surgical treatment when visual acuity drops below 6/18 from corneal edema is:
45. A contact lens wearer presents with severe pain, photophobia, and a ring-shaped corneal infiltrate. Corneal scraping stained with calcofluor white reveals double-walled cysts with polygonal morphology. Which organism is responsible and what is the first-line treatment?
46. A 30-year-old patient presents with recurrent episodes of painful red eye, blurred vision, and tearing. Slit-lamp examination reveals a geographic, map-shaped epithelial defect with dendritic borders that stains with rose Bengal at its edges but not with fluorescein at the centre. This morphology is characteristic of:
47. A patient with a history of trauma by vegetable matter develops a corneal ulcer with a feathery margin, satellite lesions, and endothelial plaques. No hypopyon is initially seen. Corneal scraping potassium hydroxide (KOH) preparation is positive. Which organism is most likely and what is the most specific treatment?
48. A patient is found to have band-shaped keratopathy on slit-lamp examination — a horizontal, chalky-white opacity across the interpalpebral zone sparing the limbus by a clear peripheral zone. What is the most likely metabolic cause in a patient with longstanding uveitis?
49. A 30-year-old contact lens wearer presents with severe ocular pain, photophobia, and a ring-shaped mid-peripheral stromal infiltrate. He reports his contact lens case contaminated with tap water. Confocal microscopy shows double-walled cysts. The most appropriate treatment is:
50. A 70-year-old patient with Fuchs' endothelial dystrophy undergoes Descemet membrane endothelial keratoplasty (DMEK) rather than penetrating keratoplasty. The primary advantage of DMEK over full-thickness PK is:
51. A contact lens wearer presents with a painful red eye, photophobia, and a corneal ulcer that is ring-shaped and involves the mid-peripheral cornea. Pain is disproportionate to clinical signs. The most likely organism and the diagnostic test are:
52. Fuchs' endothelial corneal dystrophy (FECD) is characterized by which histopathological finding on Descemet's membrane and what is the current preferred surgical treatment?
53. A contact lens wearer presents with a rapidly progressive corneal ulcer. Confocal microscopy shows double-walled, spherical cysts with internal granular material. The MOST likely causative organism is:
54. Herpes simplex virus keratitis with stromal involvement characteristically shows which pattern on slit-lamp examination?
55. Fuch's endothelial corneal dystrophy is caused by dysfunction of which corneal layer, and at what level of endothelial cell count does bullous keratopathy typically develop?
56. Acanthamoeba keratitis is characterised on confocal microscopy by which finding?
57. Acanthamoeba keratitis is most commonly associated with:
58. Terrien's marginal degeneration of the cornea is distinguished from Mooren's ulcer by which key feature?
59. A contact lens wearer presents with a painful, rapidly progressive corneal ulcer with a 'ring infiltrate'. Confocal microscopy shows hyperreflective round bodies with double-walled cysts at 4-5 μm. What organism is most likely, and what is the first-line treatment?
60. A 35-year-old farmworker presents with a whitish corneal ulcer with feathery edges and satellite lesions. Hypopyon is present. KOH examination shows branching hyphae. Corneal culture is planned. Which culture medium is MOST appropriate for this organism?
61. A 28-year-old presents with recurrent corneal dendrites, decreased corneal sensation, and a history of atopic dermatitis. PCR on corneal scraping is positive for HSV-1. Which topical antiviral is preferred for acute HSV stromal keratitis (disciform)?
62. A patient with a corneal transplant (penetrating keratoplasty) develops acute graft rejection 6 months post-operatively. The EARLIEST and MOST PATHOGNOMONIC sign of immune graft rejection is:
63. Fuchs' endothelial corneal dystrophy affects primarily the corneal endothelium. The MECHANISM of corneal oedema in this condition is:
64. Interstitial keratitis with deep corneal vascularisation (salmon patch), Hutchinson's triad, and saddle-nose deformity in a teenager suggests:
65. Interstitial keratitis (IK) due to congenital syphilis presents with corneal stromal vascularization (salmon patch). The mechanism by which Treponema pallidum causes corneal inflammation despite the organism not typically being found in the cornea is:
66. The DALK (Deep Anterior Lamellar Keratoplasty) using the Anwar big-bubble technique creates a dissection plane at the level of:
67. Salzmann's nodular degeneration of the cornea characteristically follows which pre-existing corneal condition, and its histopathological hallmark is:
68. In the pathogenesis of diabetic macular oedema (DME), the mechanism of action of fenofibrate (used in FIELD and ACCORD-EYE trials) in reducing diabetic retinopathy progression is attributed to:
69. Central serous chorioretinopathy (CSCR) is pathogenetically driven primarily by dysfunction of which cell type?
70. Congenital retinoschisis (X-linked) shows a characteristic OCT finding of splitting at which retinal layer, and which electroretinographic abnormality is diagnostic?
71. For a patient with high-risk characteristics on fluorescein angiography (FFA) following a branch retinal vein occlusion (BRVO), the Branched Retinal Vein Occlusion Study (BVOS) recommended laser treatment when: