Q.1 Which corneal layer is primarily responsible for maintaining corneal deturgescence (clarity)?
Epithelium
Bowman’s layer
Stroma
Endothelium
Explanation - The corneal endothelium maintains corneal clarity by pumping excess fluid out of the stroma.
Correct answer is: Endothelium
Q.2 What is the most common cause of infectious keratitis worldwide?
Bacteria
Virus
Fungus
Acanthamoeba
Explanation - Bacterial keratitis is the most frequent cause of infectious keratitis, especially in contact lens users.
Correct answer is: Bacteria
Q.3 Which stain is most useful for detecting corneal epithelial defects?
Giemsa
Fluorescein
Gram stain
India ink
Explanation - Fluorescein dye highlights epithelial defects under cobalt blue light.
Correct answer is: Fluorescein
Q.4 Keratoconus primarily affects which part of the cornea?
Peripheral cornea
Central and paracentral cornea
Endothelium
Limbus
Explanation - Keratoconus leads to progressive thinning and protrusion of the central/paracentral cornea.
Correct answer is: Central and paracentral cornea
Q.5 Which virus is most commonly associated with dendritic ulcers of the cornea?
Herpes simplex virus
Varicella-zoster virus
Cytomegalovirus
Epstein-Barr virus
Explanation - Herpes simplex virus causes dendritic epithelial ulcers, a hallmark of HSV keratitis.
Correct answer is: Herpes simplex virus
Q.6 What is the treatment of choice for bacterial keratitis?
Topical steroids
Topical antibiotics
Systemic antivirals
Lubricants
Explanation - Intensive topical antibiotics are first-line for bacterial keratitis to prevent perforation.
Correct answer is: Topical antibiotics
Q.7 Which corneal dystrophy is characterized by grayish opacities in the central cornea shaped like snowflakes?
Granular dystrophy
Macular dystrophy
Lattice dystrophy
Schnyder’s dystrophy
Explanation - Granular dystrophy presents with discrete white, snowflake-like opacities in the central stroma.
Correct answer is: Granular dystrophy
Q.8 Which test is most useful in early diagnosis of keratoconus?
Slit-lamp exam
Pachymetry
Keratometry
Corneal topography
Explanation - Corneal topography is the most sensitive method for detecting early keratoconus.
Correct answer is: Corneal topography
Q.9 The corneal reflex is mediated by which cranial nerves?
CN II and III
CN V and VII
CN III and VI
CN VII and IX
Explanation - Sensation is via trigeminal (V1), and motor response is via facial (VII) nerve.
Correct answer is: CN V and VII
Q.10 Which condition is associated with Kayser-Fleischer rings in the cornea?
Wilson’s disease
Keratoconus
Fuchs dystrophy
Reis-Bücklers dystrophy
Explanation - Kayser-Fleischer rings result from copper deposition at Descemet’s membrane in Wilson’s disease.
Correct answer is: Wilson’s disease
Q.11 What is the primary function of Bowman’s layer in the cornea?
Maintain hydration
Provide structural strength
Regenerate epithelium
Transmit light
Explanation - Bowman’s layer provides structural rigidity but has limited regenerative capacity.
Correct answer is: Provide structural strength
Q.12 Which condition presents with a ring-shaped corneal ulcer due to contact lens misuse?
Bacterial keratitis
Fungal keratitis
Acanthamoeba keratitis
Herpetic keratitis
Explanation - Acanthamoeba keratitis is often linked to poor contact lens hygiene and shows ring-shaped ulcers.
Correct answer is: Acanthamoeba keratitis
Q.13 What is the gold standard treatment for advanced keratoconus with severe scarring?
Contact lenses
Corneal collagen crosslinking
Intrastromal rings
Penetrating keratoplasty
Explanation - In advanced keratoconus with scarring, corneal transplantation (PK) is the definitive treatment.
Correct answer is: Penetrating keratoplasty
Q.14 Which organism commonly causes fungal keratitis following trauma with vegetative matter?
Candida
Aspergillus
Staphylococcus
Herpes simplex virus
Explanation - Filamentous fungi such as Aspergillus cause keratitis after plant/vegetative trauma.
Correct answer is: Aspergillus
Q.15 Which layer of the cornea is primarily affected in Fuchs endothelial dystrophy?
Epithelium
Stroma
Descemet’s membrane and endothelium
Bowman’s layer
Explanation - Fuchs dystrophy causes loss of endothelial cells and thickening of Descemet’s membrane.
Correct answer is: Descemet’s membrane and endothelium
Q.16 Which vitamin deficiency leads to corneal xerosis and keratomalacia?
Vitamin A
Vitamin B1
Vitamin C
Vitamin D
Explanation - Vitamin A deficiency causes xerophthalmia, Bitot’s spots, and corneal melting (keratomalacia).
Correct answer is: Vitamin A
Q.17 Which surgical procedure involves replacing only the corneal endothelium?
Penetrating keratoplasty
DALK
DSEK/DMEK
Lamellar keratoplasty
Explanation - Descemet stripping endothelial keratoplasty (DSEK/DMEK) replaces only diseased endothelium.
Correct answer is: DSEK/DMEK
Q.18 In herpes simplex keratitis, topical steroids are:
Indicated in epithelial keratitis
Contraindicated in epithelial keratitis
First-line for all types
Of no use
Explanation - Steroids worsen HSV epithelial keratitis but may be used cautiously in stromal keratitis.
Correct answer is: Contraindicated in epithelial keratitis
Q.19 What is the normal central corneal thickness?
250–350 µm
400–450 µm
500–550 µm
600–700 µm
Explanation - The average normal central corneal thickness is about 520 µm.
Correct answer is: 500–550 µm
Q.20 Band-shaped keratopathy is caused by deposition of:
Calcium
Copper
Iron
Lipids
Explanation - Band-shaped keratopathy results from calcium deposition in Bowman’s layer.
Correct answer is: Calcium
Q.21 Which clinical test detects early endothelial cell loss?
Specular microscopy
Schirmer’s test
Fluorescein staining
Tonometry
Explanation - Specular microscopy allows visualization and assessment of endothelial cell density and morphology.
Correct answer is: Specular microscopy
Q.22 Mooren’s ulcer is classified as:
Infective ulcer
Neurotrophic ulcer
Autoimmune peripheral ulcer
Traumatic ulcer
Explanation - Mooren’s ulcer is a painful, progressive, autoimmune peripheral corneal ulcer.
Correct answer is: Autoimmune peripheral ulcer
Q.23 The commonest complication of untreated corneal ulcer is:
Cataract
Glaucoma
Corneal perforation
Retinal detachment
Explanation - Progressive ulceration can lead to thinning and perforation of the cornea.
Correct answer is: Corneal perforation
Q.24 Which corneal dystrophy is autosomal recessive?
Granular
Lattice
Macular
Fuchs
Explanation - Macular corneal dystrophy is the only stromal dystrophy with autosomal recessive inheritance.
Correct answer is: Macular
Q.25 Which part of the cornea is most commonly involved in pterygium?
Superior cornea
Inferior cornea
Nasal cornea
Temporal cornea
Explanation - Pterygium most commonly encroaches from the nasal side due to sun and UV exposure.
Correct answer is: Nasal cornea