Diseases of the Cornea Practice Questions

Q: Hutchinson's rule is related to which of the following conditions?

Herpes zoster ophthalmicus. **Explanation:** **Hutchinson’s Rule** is a clinical sign used to predict ocular involvement in **Herpes Zoster Ophthalmicus (HZO)**. It states that if the tip, side, or root of the nose is involved with herpetic vesicles, there is a high probability (approx. 75%) of subsequent ocular inflammation. **1. Why Option C is Correct:** The rule is based on the anatomy of the **Nasociliary nerve**, which is a branch of the Ophthalmic division (V1) of the Trigeminal nerve. The nasociliary nerve provides sensory innervation to both the **eyeball** (via long and short ciliary nerves) and the **skin of the tip of the nose** (via the external nasal nerve). Therefore, cutaneous lesions on the nose indicate that the nasociliary nerve is involved, making intraocular inflammation (keratitis, uveitis) highly likely. **2. Why Other Options are Incorrect:** * **Option A (Herpes Simplex Keratitis):** While caused by a related virus, HSV typically presents with dendritic ulcers and does not follow the dermatomal distribution or the specific nasociliary pattern associated with Hutchinson’s rule. * **Option B (Mycotic Keratitis):** This is a fungal infection usually following trauma with vegetative matter. It presents with feathery margins and satellite lesions, unrelated to viral dermatomal patterns. **High-Yield Clinical Pearls for NEET-PG:** * **Pseudodendrite:** HZO causes "pseudodendrites" (stuck-on appearance, no terminal bulbs), unlike the true dendrites of HSV. * **Most common ocular complication of HZO:** Anterior Uveitis. * **Treatment:** Oral Acyclovir (800 mg 5x daily for 7–10 days) started within 72 hours of rash onset. * **Note:** Hutchinson’s rule is not absolute; ocular involvement can occur even if the nose is spared (approx. 30% risk).

Q: True about Fuchs endothelial dystrophy are all except?

Symmetrical and bilateral condition. **Explanation:** Fuchs Endothelial Corneal Dystrophy (FECD) is a progressive, hereditary disorder characterized by the primary loss of corneal endothelial cells. **Why Option B is the Correct Answer (The "Except"):** While FECD is a **bilateral** condition, it is characteristically **asymmetrical**. Although both eyes are affected, one eye typically shows more advanced progression or severe edema than the other. In NEET-PG, distinguishing between "bilateral and symmetrical" (typical of most dystrophies) and "bilateral but asymmetrical" (typical of Fuchs) is a high-yield point. **Analysis of Other Options:** * **Option A:** FECD shows a strong female predilection (3:1 ratio) and typically manifests in the 5th to 6th decades of life (elderly). * **Option C:** **Cornea guttata** (beaten metal appearance) is the hallmark clinical sign. These are drop-like excrescences of Descemet’s membrane resulting from endothelial dysfunction. * **Option D:** Patients often complain of **early morning blurring and halos**. This occurs because the eyelids are closed during sleep, preventing tear evaporation and increasing corneal hypoxia, which worsens stromal edema. Vision improves throughout the day as evaporation reduces the swelling. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Autosomal Dominant (most common). * **Pathophysiology:** Loss of Na+/K+ ATPase pumps in the endothelium leads to stromal and epithelial edema. * **Stages:** Starts with Guttata $\rightarrow$ Stromal Edema $\rightarrow$ Bullous Keratopathy $\rightarrow$ Corneal Scarring. * **Management:** Hypertonic saline (5% NaCl) drops/ointment; definitive treatment is Keratoplasty (DMEK/DSAEK are preferred over PK).

Q: Band-shaped keratopathy is typically seen in which of the following conditions?

Juvenile Rheumatoid Arthritis (JRA). **Explanation:** **Band-shaped Keratopathy (BSK)** is characterized by the horizontal deposition of calcium salts (hydroxyapatite) in the sub-epithelial layers, specifically the **Bowman’s membrane**, the anterior stroma, and the epithelial basement membrane. **Why Juvenile Rheumatoid Arthritis (JRA) is correct:** JRA (specifically the pauciarticular type) is the most common systemic cause of **chronic non-granulomatous uveitis** in children. Chronic intraocular inflammation leads to changes in the pH of the aqueous humor and a breakdown of the blood-aqueous barrier, promoting the precipitation of calcium in the interpalpebral fissure of the cornea. This classic triad—**Chronic Iridocyclitis, Band-shaped Keratopathy, and Complicated Cataract**—is a high-yield association for JRA. **Why other options are incorrect:** * **Rheumatoid Arthritis (RA):** While RA is a common cause of ocular manifestations, it typically presents with **Scleritis, Episcleritis, or Peripheral Ulcerative Keratitis (PUK)**. It does not characteristically cause the chronic uveitis required to trigger BSK. * **SLE and DLE:** These connective tissue disorders are more frequently associated with **Keratoconjunctivitis Sicca (Dry Eye)** or retinal vasculitis rather than calcium deposition in the cornea. **Clinical Pearls for NEET-PG:** * **Appearance:** BSK starts at the periphery (3 and 9 o'clock positions) with a characteristic **"Swiss-cheese appearance"** due to clear areas where nerves pierce the Bowman’s membrane. * **Other Causes:** Hypercalcemia (Hyperparathyroidism), chronic renal failure, and long-term exposure to mercury-containing drops (Thimerosal). * **Treatment:** The treatment of choice is **chelation** using **1.5% Disodium EDTA** after removing the corneal epithelium.

Q: A 33-year-old man presents with pain and watering of the eyes. On examination, there is a 3x2 mm greyish-white corneal ulcer with indistinct, elevated margins. The lesion is surrounded by feathery, finger-like infiltration into the adjacent corneal stroma. Minimal hypopyon is also observed. Based on the information provided, what should microbiological investigation be directed against?

Aspergillus spp.. **Explanation:** The clinical presentation is classic for **Fungal Keratitis (Keratomycosis)**. The diagnosis is clinched by the presence of a greyish-white ulcer with **indistinct, elevated margins** and characteristic **feathery, finger-like infiltrates** (satellite lesions) extending into the stroma. These features are pathognomonic for filamentous fungi, of which **Aspergillus spp.** and *Fusarium* are the most common causative agents. The presence of a "sterile" hypopyon is also frequently seen in fungal infections due to the penetration of toxins into the anterior chamber. **Analysis of Incorrect Options:** * **B. Pseudomonas spp.:** Bacterial ulcers typically present with a rapid onset, a "soupy" or liquefied appearance, and often a greenish-yellow discharge. They lack the dry, feathery borders seen here. * **C. Herpes simplex virus:** Dendritic or geographic ulcers are characteristic of HSV. These are epithelial defects with terminal bulbs and do not typically present with stromal feathery infiltrates unless there is secondary disciform keratitis. * **D. Acanthamoeba spp.:** This is usually associated with contact lens wear and presents with excruciating pain out of proportion to clinical signs, often showing a characteristic **ring-shaped infiltrate**. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factor:** History of trauma with **vegetative matter** (e.g., a branch or leaf) is the most common predisposing factor for fungal keratitis. * **Microbiology:** Gold standard investigation 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. Amphotericin B is preferred for *Candida*.

Q: Which of the following is not a cause for interstitial keratitis?

Pneumococcus. **Explanation:** **Interstitial Keratitis (IK)** is a chronic non-ulcerative inflammation of the corneal stroma, characterized by cellular infiltration and vascularization (neovascularization) without primary involvement of the epithelium or endothelium. It is primarily an **immune-mediated (Type IV hypersensitivity)** response to a systemic infection rather than a direct invasion by the pathogen. **Why Pneumococcus is the correct answer:** * **Pneumococcus (*Streptococcus pneumoniae*)** is a pyogenic bacterium that typically causes **acute bacterial keratitis** (hypopyon ulcers). It leads to rapid tissue destruction, suppuration, and ulceration of the corneal epithelium. It does not trigger the chronic, immune-mediated stromal inflammation characteristic of Interstitial Keratitis. **Why the other options are incorrect:** * **Syphilis:** The most common cause of IK. Congenital syphilis typically presents with bilateral IK (often part of Hutchinson’s triad), while acquired syphilis usually presents unilaterally. * **Tuberculosis:** A well-known cause of IK, usually presenting as a unilateral, peripheral sectoral inflammation. * **Leprosy:** Chronic infection by *Mycobacterium leprae* can lead to IK, often associated with thickened corneal nerves and avascular keratitis. **High-Yield Clinical Pearls for NEET-PG:** * **Hutchinson’s Triad:** Interstitial keratitis, Hutchinson’s teeth (notched incisors), and 8th nerve deafness. * **Salmon Patch Appearance:** A characteristic clinical sign of the active stage of syphilitic IK, caused by intense deep vascularization in the stroma. * **Ghost Vessels:** After the inflammation subsides, the cleared vessels remain as empty channels in the stroma, visible on slit-lamp examination. * **Other Causes:** Cogan syndrome (IK + vestibuloauditory symptoms), Sarcoidosis, and viral infections (HSV, VZV, Mumps).

Q: Herpetic keratitis is treated by:

Idoxuridine. **Explanation:** **1. Why Idoxuridine is Correct:** Herpetic keratitis is caused by the **Herpes Simplex Virus (HSV)**. The mainstay of treatment is antiviral therapy. **Idoxuridine** was the first antiviral agent developed for clinical use; it is a pyrimidine analogue that inhibits viral DNA synthesis by substituting for thymidine. While newer drugs like Acyclovir and Ganciclovir are now preferred due to lower toxicity, Idoxuridine remains the classic pharmacological answer for treating epithelial HSV keratitis. **2. Why Other Options are Incorrect:** * **Analgesics (A):** While they may provide symptomatic relief for pain, they do not treat the underlying viral infection. * **Atropine (B):** Atropine is a cycloplegic used as an *adjunct* therapy in keratitis to relieve ciliary spasms and prevent posterior synechiae, but it is not the primary curative treatment. * **Steroids (C):** **Contraindicated** in active epithelial (dendritic) herpetic keratitis. Steroids promote viral replication and can lead to the formation of a "Geographic ulcer" or even corneal perforation. **3. High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Topical **Acyclovir (3%)** or **Ganciclovir (0.15%)** are currently the drugs of choice. * **Classic Sign:** The hallmark of HSV epithelial keratitis is the **Dendritic Ulcer** (linear branching with terminal bulbs), which stains with Fluorescein. * **The "Steroid Rule":** Never use steroids in a dendritic ulcer. Steroids are only used in *Stromal* (Disciform) keratitis under strict antiviral cover. * **Trifluorothymidine (Trifluridine):** Another antiviral used, especially for cases resistant to Idoxuridine.

Q: Which of the following statements about band-shaped keratopathy is true?

Sarcoidosis can be a cause.. **Band-shaped Keratopathy (BSK)** is a degenerative condition characterized by the deposition of **calcium salts** (hydroxyapatite) in the subepithelial layers, specifically the **Bowman’s membrane**, the anterior stroma, and the epithelial basement membrane. ### **Explanation of Options:** * **Option D (Correct):** BSK is associated with systemic conditions that cause **hypercalcemia**, such as **sarcoidosis**, hyperparathyroidism, vitamin D toxicity, and milk-alkali syndrome. Chronic ocular inflammation (like juvenile idiopathic arthritis-associated uveitis) and long-term exposure to mercurial preservatives are also common causes. * **Option A & B (Incorrect):** The hallmark of BSK is the deposition of **calcium**, not iron. Furthermore, this deposition occurs primarily in the **Bowman’s membrane**, not the Descemet’s membrane. (Note: Iron deposition in the cornea is seen in conditions like Fleischer rings in keratoconus or Hudson-Stahli lines). * **Option C (Incorrect):** Since the deposits are calcium-based, the treatment of choice is **chelation using EDTA** (Ethylenediamine tetraacetic acid), a calcium-chelating agent, followed by mechanical scraping (debridement). ### **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** It typically starts at the periphery (3 and 9 o’clock positions) and progresses centrally as a horizontal "band." * **Lucent Zones:** A characteristic feature is the presence of **clear "holes"** within the calcium plaque, which represent areas where corneal nerves pierce the Bowman’s membrane. * **Clear Margin:** There is always a distinct **clear zone** between the peripheral edge of the calcification and the limbus (due to the absence of Bowman's membrane at the limbus). * **Most Common Ocular Cause:** Chronic uveitis (especially in children with JIA).

Question 1

Hutchinson's rule is related to which of the following conditions?

Accepted Answer

Herpes zoster ophthalmicus

Answer

Herpes simplex keratitis

Answer

Mycotic keratitis

Answer

None of the above

Question 2

True about Fuchs endothelial dystrophy are all except?

Accepted Answer

Symmetrical and bilateral condition

Answer

Commonly seen in the elderly female

Answer

Cornea guttatae is characteristic

Answer

Patient typically complains of seeing halos in the morning

Question 3

Band-shaped keratopathy is typically seen in which of the following conditions?

Accepted Answer

Juvenile Rheumatoid Arthritis (JRA)

Answer

Rheumatoid Arthritis (RA)

Answer

Systemic Lupus Erythematosus (SLE)

Answer

Discoid Lupus Erythematosus (DLE)

Question 4

A 33-year-old man presents with pain and watering of the eyes. On examination, there is a 3x2 mm greyish-white corneal ulcer with indistinct, elevated margins. The lesion is surrounded by feathery, finger-like infiltration into the adjacent corneal stroma. Minimal hypopyon is also observed. Based on the information provided, what should microbiological investigation be directed against?

Accepted Answer

Aspergillus spp.

Answer

Pseudomonas spp.

Answer

Herpes simplex virus

Answer

Acanthamoeba spp.

Question 5

Band shaped keratopathy is typically seen in which of the following conditions?

Accepted Answer

Chronic uveitis

Answer

Rheumatoid arthritis

Answer

Systemic lupus erythematosus

Answer

Discoid lupus erythematosus

Question 6

Corneal transparency is due to all of the following EXCEPT:

Accepted Answer

Hypercellular stroma

Answer

Na+–K+ pump

Answer

Normal intraocular pressure

Answer

Peculiar arrangement of lamellae

Question 7

Which of the following is not a cause for interstitial keratitis?

Accepted Answer

Pneumococcus

Answer

Syphilis

Answer

Leprosy

Answer

Tuberculosis

Question 8

Herpetic keratitis is treated by:

Accepted Answer

Idoxuridine

Answer

Analgesics

Answer

Atropine

Answer

Steroids

Question 9

The corneal transparency is maintained by –

Accepted Answer

Endothelium

Answer

Keratocytes

Answer

Bowman's membrane

Answer

Descemet's membrane

Question 10

Which of the following statements about band-shaped keratopathy is true?

Accepted Answer

Sarcoidosis can be a cause.

Answer

Iron deposition occurs in Bowman's membrane.

Answer

Calcium deposition occurs in Descemet's membrane.

Answer

Iron chelating agents are used for treatment.

Diseases of the Cornea — MCQs

Diseases of the Cornea — MCQs

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