Diseases of the Cornea Practice Questions

Q: Keratomalacia is associated with which of the following infections?

Measles. **Explanation:** **Keratomalacia** is the most severe stage of **Xerophthalmia**, characterized by rapid, liquefactive necrosis of the corneal stroma. It typically occurs in children with severe Vitamin A deficiency. **Why Measles is the Correct Answer:** Measles (Rubeola) is a major precipitating factor for keratomalacia in developing countries. The infection causes a "triple threat" to the cornea: 1. **Metabolic Stress:** It acutely depletes systemic Vitamin A stores. 2. **Direct Damage:** The virus causes viral keratitis and conjunctivitis. 3. **Secondary Infection:** It leads to immunosuppression, predisposing the cornea to secondary bacterial or fungal infections. This combination leads to rapid corneal melting and perforation. **Analysis of Incorrect Options:** * **Herpes Simplex (HSV):** Typically causes dendritic or geographic ulcers and disciform keratitis. While it can cause stromal melting (necrotizing keratitis), it is not classically associated with the systemic nutritional deficiency defined as keratomalacia. * **Varicella Zoster (VZV):** Causes Herpes Zoster Ophthalmicus (HZO) characterized by pseudodendrites and neurotrophic keratopathy, but not the liquefactive necrosis seen in keratomalacia. * **Diphtheria:** *Corynebacterium diphtheriae* is known for causing **membranous conjunctivitis**. While it can lead to corneal ulceration, it is not the primary infectious trigger for keratomalacia. **High-Yield Clinical Pearls for NEET-PG:** * **WHO Classification of Xerophthalmia:** Keratomalacia is classified as **X3A** (involving 1/3 of the cornea). * **Bitot’s Spots (X1B):** Triangular, foamy patches on the bulbar conjunctiva (Corynebacterium xerosis). * **Treatment:** Immediate administration of Vitamin A (200,000 IU orally on days 0, 1, and 14) is life-saving and sight-saving. * **Measles Vaccine:** Is considered a key intervention in preventing nutritional blindness worldwide.

Q: Which of the following is not an association for Keratoconus?

Senile cataract. **Explanation:** Keratoconus is a progressive, non-inflammatory thinning and ectasia of the cornea, leading to irregular astigmatism. It is frequently associated with systemic connective tissue disorders and conditions that involve chronic eye rubbing. **Why Senile Cataract is the correct answer:** Senile cataract is an age-related degenerative change of the crystalline lens. There is no pathophysiological link between the development of keratoconus (which typically manifests in puberty or early adulthood) and senile cataracts (which occur in the elderly). While a patient with keratoconus will eventually age and develop cataracts, it is not considered a clinical "association" or risk factor. **Analysis of Incorrect Options:** * **Marfan Syndrome:** This is a systemic connective tissue disorder (Fibrillin-1 mutation). The structural weakness in the collagen matrix of the cornea in these patients predisposes them to keratoconus. * **Leber Congenital Amaurosis (LCA):** Patients with LCA often have poor vision from birth and frequently perform the **"Oculodigital sign"** (poking/rubbing eyes to stimulate the retina). Chronic mechanical trauma from eye rubbing is a major risk factor for keratoconus. * **Vernal Keratoconjunctivitis (VKC):** This is a severe allergic condition. The intense itching leads to vigorous, chronic eye rubbing, which is the primary mechanism linking VKC to the development of keratoconus. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Associations:** "MR. T" (Down's, Marfan's, Retinitis pigmentosa, Atopic dermatitis, Turner syndrome). * **Early Sign:** Fleischer’s ring (iron deposition at the base of the cone). * **Late Sign:** Munson’s sign (indentation of the lower lid on downgaze). * **Acute Hydrops:** Caused by a rupture in **Descemet’s membrane**, leading to sudden corneal edema. * **Treatment of Choice (Early):** C3R (Corneal Collagen Cross-linking with Riboflavin) to stop progression.

Q: What is the recommended time frame for performing a corneal transplant after death?

Within 2 hours of death. **Explanation:** The viability of corneal tissue is highly dependent on the health of the **corneal endothelium**, which does not regenerate. To ensure a successful transplant (Keratoplasty), the donor eyes must be harvested as soon as possible to prevent autolysis and exposure-related damage. * **Why Option B is Correct:** In ideal clinical practice, the recommended time frame for enucleation (removal of the eye) or in-situ corneal excision is **within 2 hours of death**. This minimizes the risk of endothelial cell loss and ensures the graft remains clear after surgery. While harvesting can technically be performed up to 6 hours post-mortem (especially if the body is refrigerated), the "ideal" or "recommended" standard taught for competitive exams like NEET-PG is 2 hours. * **Why Options A & C are Incorrect:** While harvesting within 30 minutes or 1 hour would provide excellent tissue, it is logistically impractical in most clinical settings. These time frames are not the standard recommendation. * **Why Option D is Incorrect:** By 5 hours, significant epithelial sloughing and endothelial degradation may have begun, especially if the cadaver was kept at room temperature. While 6 hours is often cited as the *upper limit*, it is not the *recommended* ideal window. **High-Yield Clinical Pearls for NEET-PG:** * **Storage Media:** Short-term (48 hours) in **MK Medium**; Intermediate (up to 2 weeks) in **Optisol-GS** (most common); Long-term (months) via **Cryopreservation**. * **Age Limit:** Donor age is ideally between 2 to 70 years. * **Contraindications for Donation:** Death of unknown cause, HIV, Hepatitis B/C, Rabies, Syphilis, Leukemia, and Creutzfeldt-Jakob disease. * **Endothelial Count:** A donor cornea is generally considered suitable for transplant if the endothelial cell count is **>2000 cells/mm²**.

Q: Disciform herpetic keratitis involves which layer of the cornea?

Endothelium. **Explanation:** **Disciform Keratitis** is a type of **Endotheliitis** caused by a delayed-type hypersensitivity reaction (Type IV) to the Herpes Simplex Virus (HSV) antigen. 1. **Why Endothelium is correct:** In disciform keratitis, the primary site of inflammation is the **corneal endothelium**. The inflammatory process leads to endothelial pump failure, resulting in localized, disc-shaped stromal edema. A hallmark clinical finding is the presence of **Keratic Precipitates (KPs)** directly underlying the area of edema, signifying endothelial involvement. 2. **Why other options are incorrect:** * **Epithelium:** Epithelial involvement is characteristic of *Dendritic* or *Geographic* ulcers (active viral replication), not disciform keratitis. * **Descemet’s Membrane:** While it may show folds (striate keratopathy) due to overlying edema, it is a basement membrane and not the primary site of the immunological trigger. * **Basement Membrane:** This layer is involved in epithelial adhesion; damage here leads to recurrent epithelial erosions, not the deep stromal edema seen in disciform disease. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Central/paracentral disc-shaped stromal edema, KPs, and often increased Intraocular Pressure (IOP). * **Wessely Ring:** An immune ring of stromal precipitation may sometimes be seen surrounding the edema. * **Sensation:** Corneal sensations are typically **diminished or absent** (a classic HSV feature). * **Management:** Unlike epithelial herpes (where steroids are contraindicated), Disciform Keratitis is treated with **topical steroids** to dampen the immune response, always covered by **prophylactic topical antivirals** (e.g., Ganciclovir/Acyclovir) to prevent viral reactivation.

Q: Which of the following is NOT true about herpetic keratitis?

Corneal guttata. **Explanation:** Herpetic keratitis is caused by the **Herpes Simplex Virus (HSV)** and is a leading cause of corneal blindness. It typically presents in various clinical forms depending on whether the infection is an active viral replication (epithelial) or an immune-mediated response (stromal/endothelial). **Why "Corneal Guttata" is the correct answer:** Corneal guttata refers to drop-like collagenous deposits on the Descemet membrane, representing focal dysfunction of the corneal endothelial cells. This is the hallmark clinical sign of **Fuchs’ Endothelial Corneal Dystrophy (FECD)**, a genetic degenerative condition. It is not caused by viral infections like HSV. **Analysis of incorrect options:** * **Dendritic Ulcer:** This is the most characteristic presentation of **Epithelial Keratitis**. It features a linear, branching ulcer with "terminal bulbs" that stain brightly with fluorescein. * **Stromal Keratitis:** This occurs due to an immune-mediated response to viral antigens. It can present as *Interstitial Keratitis* (infiltrates and vascularization) or *Necrotizing Stromal Keratitis* (direct viral invasion leading to necrosis/perforation). * **Disciform Keratitis:** This is a form of **Endotheliitis**. It presents as a central, disc-shaped area of stromal edema without significant infiltration, caused by a delayed hypersensitivity reaction to the virus. **High-Yield Clinical Pearls for NEET-PG:** * **Staining:** Dendritic ulcers stain with **Fluorescein** (base of the ulcer) and **Rose Bengal** (devitalized cells at the margins). * **Sensation:** A key diagnostic feature of herpetic keratitis is **decreased corneal sensations** (hypoesthesia). * **Treatment:** Topical **Acyclovir (3%)** or Ganciclovir is the drug of choice for epithelial disease. **Steroids** are strictly contraindicated in dendritic ulcers but are the mainstay of treatment for Disciform Keratitis (always used under antibiotic/antiviral cover).

Q: Which of the following fungal infections most commonly causes corneal ulcers?

Aspergillus. **Explanation:** **Aspergillus** is the most common cause of fungal keratitis (corneal ulcers) worldwide, particularly in tropical and subtropical regions like India. Fungal ulcers typically occur following **vegetative trauma** (e.g., injury with a branch, leaf, or agricultural product). Aspergillus species are ubiquitous filamentous fungi that easily invade the corneal stroma, often leading to a characteristic "dry," grayish-white infiltrate with feathery margins. **Analysis of Incorrect Options:** * **Trichophyton:** This is a dermatophyte primarily responsible for superficial skin, hair, and nail infections (Tinea). It rarely involves the cornea. * **Mucor:** While Mucor can cause devastating **Rhino-oculo-cerebral mucormycosis** (especially in uncontrolled diabetics), it typically presents as an invasive orbital cellulitis rather than a primary corneal ulcer. * **Sporothrix:** This causes Sporotrichosis ("Rose gardener’s disease"), which usually presents as chronic granulomatous nodules along lymphatic channels. Ocular involvement is rare and usually affects the conjunctiva or lacrimal apparatus. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause in India:** *Aspergillus* is the overall leader, though *Fusarium* is also highly prevalent in southern regions. * **Most common cause in temperate climates/USA:** *Candida* (yeast). * **Clinical Signs:** Look for **feathery margins**, **satellite lesions**, and a **fixed hypopyon** (which does not shift with head position due to its thick, fibrinous nature). * **Diagnosis:** Gold standard is corneal scraping for **KOH mount** (shows hyphae) and culture on **Sabouraud’s Dextrose Agar (SDA)**. * **Treatment:** Topical **Natamycin (5%)** is the drug of choice for filamentous fungi like Aspergillus.

Q: Which of the following type of corneal degeneration is associated with formation of drop-like excrescences of hyaline material which project into the anterior chamber around the corneal periphery?

Hassall-Henle bodies. ### Explanation **Correct Answer: B. Hassall-Henle bodies** **Hassall-Henle bodies** are a physiological age-related change characterized by the formation of small, drop-like excrescences of hyaline material. These represent focal thickenings of the **Descemet’s membrane** that project into the anterior chamber. Crucially, they are located in the **corneal periphery**. While they are histologically identical to "Guttata," the term Hassall-Henle bodies is reserved for these peripheral changes seen in normal aging, whereas central guttata are characteristic of Fuchs' endothelial dystrophy. **Analysis of Incorrect Options:** * **A. Vogt's limbal girdle:** This is a common, benign, age-related degeneration appearing as narrow, crescentic white lines in the interpalpebral area of the peripheral cornea (nasal and temporal). It involves subepithelial elastotic degeneration, not Descemet’s membrane. * **C. Lipoid keratopathy:** This involves the deposition of lipids (cholesterol, lecithin) in the corneal stroma. It can be primary or secondary (following vascularization due to trauma or keratitis) and presents as opaque, yellowish-white deposits. * **D. Hyaline degeneration:** This is a broad term often associated with Salzmann’s nodular degeneration or Spheroidal degeneration. It involves the replacement of Bowman’s membrane and superficial stroma with hyaline material, but it does not project from the Descemet’s membrane into the anterior chamber. **High-Yield Clinical Pearls for NEET-PG:** * **Hassall-Henle bodies = Peripheral** (Normal aging). * **Corneal Guttata = Central** (Pathological; hallmark of Fuchs' Endothelial Corneal Dystrophy). * Both appear as "beaten silver" or "orange peel" appearances on specular microscopy. * **Arcus Senilis** is the most common peripheral corneal degeneration, involving lipid deposition starting at the superior and inferior poles.

Q: Which of the following is NOT a cause of enlarged corneal nerves?

Band-shaped keratopathy. **Explanation:** The presence of thickened or prominent corneal nerves is a specific clinical sign observed during slit-lamp examination. This occurs due to the proliferation of Schwann cells or the accumulation of abnormal materials within the nerve sheaths. **Why Band-shaped Keratopathy (BSK) is the correct answer:** Band-shaped keratopathy is a degenerative condition characterized by the deposition of **calcium salts (hydroxyapatite)** in the subepithelial layers, specifically the Bowman’s membrane. It is associated with chronic intraocular inflammation (e.g., Uveitis), hypercalcemia, or silicone oil in the anterior chamber. It does **not** involve the corneal nerves; rather, it presents as a horizontal "Swiss-cheese" pattern of calcification across the interpalpebral fissure. **Analysis of Incorrect Options (Causes of Enlarged Corneal Nerves):** * **Neurofibromatosis (Type 1):** A classic cause where nerve sheath tumors (neurofibromas) and thickened nerves occur throughout the body, including the cornea. * **Riley-Day Dysautonomia (Hereditary Sensory and Autonomic Neuropathy Type III):** Characterized by a lack of fungiform papillae on the tongue and prominent corneal nerves, often leading to neurotrophic keratitis. * **Multiple Endocrine Neoplasia (MEN Type 2B):** This is a high-yield association. Patients present with medullary carcinoma of the thyroid, pheochromocytoma, and mucosal neuromas. Thickened corneal nerves are a hallmark ocular finding. **NEET-PG Clinical Pearls:** To remember the causes of enlarged corneal nerves, use the mnemonic **"MEN CAN"**: * **M:** **M**EN Type 2B, **M**edullary carcinoma of thyroid * **E:** **E**dema (Corneal hydrops in Keratoconus) * **N:** **N**eurofibromatosis, **N**eoplasia * **C:** **C**ongenital Glaucoma * **A:** **A**canthamoeba keratitis (Radial keratoneuritis—highly painful) * **N:** **N**eoplasia / **N**oonan Syndrome / **N**euroleprosy (rarely)

Q: Megalocornea is not seen in which of the following conditions?

Congenital Rubella. **Explanation:** **Megalocornea** is a non-progressive, bilateral condition characterized by an increased corneal diameter (typically >13 mm) at birth, in the absence of elevated intraocular pressure. **Why Congenital Rubella is the correct answer:** Congenital Rubella Syndrome (CRS) is classically associated with **Microcornea** (corneal diameter <10 mm) and **Microphthalmos**, rather than Megalocornea. While CRS can cause "Infantile Glaucoma" (which might lead to secondary corneal enlargement or *Buphthalmos*), the primary developmental anomaly associated with Rubella is a small cornea. **Analysis of Incorrect Options:** * **Marfan Syndrome:** This is a well-known systemic association of Megalocornea. Patients often present with large corneas, flat curvatures (*Cornea Plana*), and ectopia lentis. * **Alport Syndrome:** This hereditary nephritis is associated with several ocular features, including anterior lenticonus and Megalocornea. * **Down’s Syndrome (Trisomy 21):** While Keratoconus is the most common corneal association in Down’s syndrome, Megalocornea is also a documented clinical finding in these patients. **High-Yield Clinical Pearls for NEET-PG:** 1. **Megalocornea vs. Buphthalmos:** In Megalocornea, the intraocular pressure (IOP) is normal, the optic disc is healthy, and the cornea is clear. In Buphthalmos (Congenital Glaucoma), the cornea is large but associated with high IOP, Haab’s striae, and optic disc cupping. 2. **Inheritance:** Simple Megalocornea is most commonly **X-linked recessive** (90% of cases occur in males). 3. **Other Associations:** Megalocornea is also seen in **Osteogenesis Imperfecta**, **Ehlers-Danlos Syndrome**, and **Mucopolysaccharidosis**. 4. **Surgical Risk:** Patients with Megalocornea have a very deep anterior chamber, making them prone to lens subluxation and vitreous loss during cataract surgery.

Q: Brown discoloration of the cornea is seen in which of the following conditions?

All of the above. **Explanation:** Brown discoloration of the cornea (keratopathy) occurs due to the deposition of metallic particles or chemical pigments within the corneal layers. 1. **Siderosis (Iron deposition):** When an intraocular iron-containing foreign body is retained, it undergoes oxidation. The resulting iron salts deposit in the corneal stroma and epithelial cells, leading to a characteristic **rusty-brown** discoloration. 2. **Mustard Gas Exposure:** Delayed keratitis is a known complication of mustard gas (sulfur mustard) exposure. It leads to a "marbled" appearance of the cornea with **brownish pigmentation**, often associated with vascularization and fatty degeneration. 3. **Chalcosis (Copper deposition):** While copper is classically associated with the "Sunflower cataract" and the "Kayser-Fleischer (KF) ring" (a golden-brown ring in Descemet’s membrane), heavy copper deposition can result in a generalized **greenish-brown** hue to the cornea. **Clinical Pearls for NEET-PG:** * **Kayser-Fleischer (KF) Ring:** A pathognomonic sign of **Wilson’s Disease** (Hepatolenticular degeneration). It is a golden-brown/greenish deposit of copper in the **Descemet’s membrane**, starting at the 12 and 6 o'clock positions. * **Hudson-Stahli Line:** A horizontal brown line of **iron deposition** seen at the junction of the upper 2/3 and lower 1/3 of the cornea (physiologic aging). * **Flecked/Vortex Keratopathy (Cornea Verticillata):** Golden-brown whorl-like deposits in the basal epithelium, seen in **Fabry’s disease** or chronic **Amiodarone/Chloroquine** use. * **Stocker’s Line:** Iron line seen at the head of a **Pterygium**. * **Ferry’s Line:** Iron line seen at the edge of a **Filtering Bleb**.

Question 1

Keratomalacia is associated with which of the following infections?

Accepted Answer

Measles

Answer

Herpes simplex

Answer

Varicella zoster

Answer

Diphtheria

Question 2

Which of the following is not an association for Keratoconus?

Accepted Answer

Senile cataract

Answer

Marfan syndrome

Answer

Leber congenital amaurosis

Answer

Vernal keratoconjunctivitis

Question 3

What is the recommended time frame for performing a corneal transplant after death?

Accepted Answer

Within 2 hours of death

Answer

Within 1 hour of death

Answer

Within 30 minutes of death

Answer

Within 5 hours of death

Question 4

Disciform herpetic keratitis involves which layer of the cornea?

Accepted Answer

Endothelium

Answer

Epithelium

Answer

Descemet's membrane

Answer

Basement membrane

Question 5

Which of the following is NOT true about herpetic keratitis?

Accepted Answer

Corneal guttata

Answer

Stromal Keratitis

Answer

Dendritic Ulcer

Answer

Disciform Keratitis

Question 6

Which of the following fungal infections most commonly causes corneal ulcers?

Accepted Answer

Aspergillus

Answer

Trichophyton

Answer

Mucor

Answer

Sporothrix

Question 7

Which of the following type of corneal degeneration is associated with formation of drop-like excrescences of hyaline material which project into the anterior chamber around the corneal periphery?

Accepted Answer

Hassall-Henle bodies

Answer

Vogt's limbal girdle

Answer

Lipoid keratopathy

Answer

Hyaline degeneration

Question 8

Which of the following is NOT a cause of enlarged corneal nerves?

Accepted Answer

Band-shaped keratopathy

Answer

Neurofibromatosis

Answer

Riley-Day dysautonomia

Answer

Multiple endocrine neoplasia (MEN)

Question 9

Megalocornea is not seen in which of the following conditions?

Accepted Answer

Congenital Rubella

Answer

Marfan Syndrome

Answer

Alport syndrome

Answer

Down's syndrome

Question 10

Brown discoloration of the cornea is seen in which of the following conditions?

Accepted Answer

All of the above

Answer

Siderosis

Answer

Mustard gas exposure

Answer

Chalcosis

Diseases of the Cornea — MCQs

Diseases of the Cornea — MCQs

On this page

Practice by Chapter

Want unlimited practice?