Diseases of the Cornea Practice Questions

Q: Which of the following is not a phase involved in corneal epithelial repair?

Cell fusion. ***Cell fusion*** - Cell fusion, the **merging of cell membranes** from two or more cells to form a single cell, is not recognized as a mechanism involved in typical corneal epithelial repair. - Corneal epithelial healing primarily relies on the coordinated actions of **migration**, **proliferation**, and **differentiation** of existing cells. *Cell migration* - **Epithelial cells** at the wound edge flatten and migrate to cover the denuded area, forming a monolayer. - This initial phase is crucial for rapidly **closing the defect** and preventing infection. *Cell adhesion* - New cells need to **adhere to the underlying basement membrane** and to each other to maintain structural integrity. - **Integrins** and other adhesion molecules play a critical role in re-establishing proper connections. *Cell proliferation* - Once the defect is covered by migrating cells, **basal cells** begin to proliferate to restore the original cell layers and thickness of the epithelium. - This phase rebuilds the **stratified squamous epithelium**.

Q: Topical antifungal of choice for Aspergillus infection of the eye?

Natamycin. ***Natamycin*** - **Natamycin (Natacyn) 5%** is the **only FDA-approved topical antifungal** for ophthalmic use and is the **drug of choice** for fungal keratitis caused by filamentous fungi, including *Aspergillus*. - It is a **polyene antifungal** with excellent activity against *Aspergillus* species and has **good corneal penetration** when applied topically. - Natamycin is considered the **gold standard** for treating *Aspergillus* keratitis and is the **first-line agent** for this condition. *Fluconazole* - **Fluconazole** is a triazole antifungal with **poor activity against *Aspergillus* species**. - It is primarily effective against yeasts like *Candida* species, not filamentous fungi. - Fluconazole has **limited role** in treating *Aspergillus* eye infections and is NOT used as a topical agent for this indication. *Miconazole* - **Miconazole** is an imidazole antifungal with limited use in ophthalmic infections. - It has **poor ocular penetration** and is not considered a first-line agent for *Aspergillus* keratitis. *Clotrimazole* - **Clotrimazole** is primarily used for cutaneous and superficial fungal infections. - It has **limited systemic absorption and poor ocular penetration**, making it unsuitable for *Aspergillus* eye infections. - It is not routinely used as a topical ophthalmic antifungal agent.

Q: Munson's sign is a feature of ?

Keratoconus. ***Keratoconus*** - **Munson's sign** is observed in advanced keratoconus, where the **conical protrusion of the cornea** indents the lower eyelid on downgaze. - This sign indicates significant **corneal thinning and steepening**. *Corneal ulcer* - A **corneal ulcer** is an open sore on the cornea, often caused by infection or trauma. - It presents with pain, redness, tearing, and photophobia, and does not cause **Munson's sign**. *Pterygium* - **Pterygium** is a triangular growth of conjunctival tissue that extends onto the cornea. - It is typically associated with UV exposure and does not cause corneal shape changes leading to **Munson's sign**. *Posterior staphyloma* - A **posterior staphyloma** is an outpouching of the posterior sclera, often seen in high myopia. - This condition affects the posterior segment of the eye and does not manifest with **Munson's sign**, which is an anterior corneal finding.

Q: All are true about Bullous keratopathy except which of the following?

Seen in Macular dystrophy. ***Seen in Macular dystrophy*** - **Bullous keratopathy** is a condition caused by endothelial dysfunction leading to corneal edema and bullae formation. - While macular corneal dystrophy is a condition characterized by corneal clouding due to mucopolysaccharide deposits in the stroma, it typically does not directly cause bullous keratopathy. *Treatment is lamellar keratoplasty* - **Lamellar keratoplasty** (e.g., DSAEK, DMEK) is a common surgical treatment for bullous keratopathy, where diseased posterior corneal layers are replaced. - The goal is to replace the dysfunctional endothelium and restore corneal clarity and function. *Lenses can be prescribed for such patients* - **Contact lenses**, particularly bandage contact lenses, can be prescribed to patients with bullous keratopathy to protect the cornea and alleviate pain. - They act as a physical barrier against ruptured bullae, promoting epithelial healing and comfort. *Seen in Fuchs' dystrophy* - **Fuchs' endothelial dystrophy** is a common cause of bullous keratopathy, where there's a progressive loss of corneal endothelial cells. - This endothelial dysfunction leads to an accumulation of fluid within the cornea, causing edema and the formation of epithelial bullae.

Q: Quantification of corneal sensation is done by?

Aesthesiometer. ***Aesthesiometer*** - An **aesthesiometer** is a specialized device used to measure the **corneal sensation** or sensitivity, typically by applying a controlled stimulus to the corneal surface. - It helps in diagnosing conditions affecting **corneal nerves**, such as **diabetic neuropathy** or post-surgical nerve damage. *Pachymeter* - A **pachymeter** is an ultrasonic device used to measure the **central corneal thickness (CCT)**. - This measurement is crucial for **intraocular pressure (IOP)** interpretation and evaluating conditions like **corneal edema** or **Fuchs' endothelial dystrophy**. *Keratometer* - A **keratometer** is an ophthalmic instrument used to measure the **curvature of the anterior surface of the cornea**. - It is primarily used to assess **corneal astigmatism** and to fit **contact lenses**. *Tonometer* - A **tonometer** is an instrument used to measure **intraocular pressure (IOP)**, which is essential for diagnosing and managing **glaucoma**. - It does not quantify corneal sensation but rather the **fluid pressure within the eye**.

Q: What is the dye and filter used to diagnose corneal ulcers?

Fluorescein dye - visualized under cobalt blue filter. ***Fluorescein dye - visualized under cobalt blue filter*** - **Fluorescein dye** is applied to the eye, and it stains areas of **epithelial defects**, such as those found in corneal ulcers, appearing bright green. - The **cobalt blue filter** enhances the visibility and fluorescence of the stained areas, making corneal ulcers clearly discernible. *Lissamine green dye - visualized under green filter* - **Lissamine green** is used to identify **devitalized cells** and **mucous filaments** on the ocular surface, rather than primary corneal epithelial defects. - It is visualized under **white light or red-free filter**, not a green filter, and is less suitable for diagnosing corneal ulcers directly. *Lissamine blue dye - visualized under cobalt blue filter* - This option refers to a non-existent dye combination for routine corneal ulcer diagnosis. **Lissamine blue** is not a standard ophthalmic dye for this purpose. - While a cobalt blue filter is used with fluorescein, it is not paired with a "Lissamine blue dye." *Fluorescein dye - visualized under green filter* - **Fluorescein dye** is indeed the correct dye for diagnosing corneal ulcers by staining epithelial defects. - However, it is visualized under a **cobalt blue filter**, not a green filter, to maximize fluorescence and contrast.

Q: What is a characteristic finding in fungal corneal ulcers?

Satellite lesions. ***Satellite lesions*** - **Fungal corneal ulcers** often present with characteristic **satellite lesions**, which are smaller, adjacent infiltrates surrounding the main ulcer. - These lesions indicate the spread of fungal hyphae into the surrounding corneal stroma. - This is the **most characteristic feature** that helps distinguish fungal from bacterial keratitis. *Dendritic ulcer* - A **dendritic ulcer** is pathognomonic for **herpes simplex keratitis**, not fungal infections. - It presents as a branching, tree-like epithelial defect, which is distinct from the appearance of fungal ulcers. *Ring abscess* - A **ring abscess** is more commonly associated with **Acanthamoeba keratitis** or severe bacterial infections. - While it can occur in very advanced fungal infections, it is not a characteristic initial finding. *White hypopyon* - While fungal keratitis can present with a **white, fluffy hypopyon**, this is not specific enough to be the most characteristic finding. - Hypopyon indicates severe inflammation and can be seen in bacterial, fungal, and other severe corneal infections. - The presence of **satellite lesions** remains the key distinguishing feature for fungal etiology.

Q: All of the following are true about Keratoconus, except:

Thick cornea. ***Thick cornea*** - Keratoconus is characterized by **progressive corneal thinning** and weakening, not thickening. - This corneal thinning leads to a conical protrusion, causing significant visual distortion and irregular astigmatism. *Increased curvature of cornea and Astigmatism* - Keratoconus features **increased corneal curvature** with progressive steepening into a cone-shaped configuration. - This results in **irregular astigmatism**, a hallmark feature causing distorted vision at all distances. *Astigmatism* - **Irregular astigmatism** is a cardinal feature of keratoconus due to the asymmetric corneal shape. - Causes blurred and distorted vision that is difficult to correct with spectacles alone. *Fleischer's ring* - **Fleischer's ring** is an iron deposit ring at the base of the cone in keratoconus, visible on slit-lamp examination. - It represents hemosiderin deposition in the basal epithelial cells and is a characteristic clinical sign of keratoconus.

Q: Unilateral frontal blisters with upper lid edema and conjunctivitis is seen in?

Herpes Zoster Ophthalmicus. ***Herpes Zoster Ophthalmicus*** - This condition is characterized by a **unilateral vesicular rash** (blisters) in the **trigeminal dermatome (V1)**, which includes the forehead and upper eyelid, along with significant **lid edema** and **conjunctivitis**. - **Hutchinson's sign** (lesions on the tip, side, or root of the nose) indicates a high risk of ocular involvement due to the nasociliary nerve innervation. *Acanthamoeba Keratitis* - This is an **amoebic infection** of the cornea typically associated with **contact lens wear** and often presents with severe pain and a **ring infiltrate** in the cornea. - It does not typically present with unilateral frontal blisters or significant lid edema. *Herpes Simplex* - Herpes simplex typically causes **recurrent corneal ulcers** (dendritic or geographic) and sometimes blepharitis, but not the widespread **unilateral frontal blisters** seen in the trigeminal distribution. - While it can cause conjunctivitis and lid edema, the pattern of skin lesions is the key differentiator. *Neuroparalytic Keratitis* - This condition results from **trigeminal nerve damage**, leading to corneal anesthesia and subsequent **trophic corneal ulceration**. - It presents primarily with **corneal findings** (epithelial defects, ulcers) due to impaired sensation and tear film stability, not initial vesicular skin lesions or prominent lid edema.

Question 1

Which of the following is not a phase involved in corneal epithelial repair?

Accepted Answer

Cell fusion

Answer

Cell migration

Answer

Cell adhesion

Answer

Cell proliferation

Question 2

Topical antifungal of choice for Aspergillus infection of the eye?

Accepted Answer

Natamycin

Answer

Clotrimazole

Answer

Miconazole

Answer

Fluconazole

Question 3

Munson's sign is a feature of ?

Accepted Answer

Keratoconus

Answer

Corneal ulcer

Answer

Pterygium

Answer

Posterior staphyloma

Question 4

All are true about Bullous keratopathy except which of the following?

Accepted Answer

Seen in Macular dystrophy

Answer

Lenses can be prescribed for such patients

Answer

Seen in Fuchs' dystrophy

Answer

Treatment is lamellar keratoplasty

Question 5

Quantification of corneal sensation is done by?

Accepted Answer

Aesthesiometer

Answer

Pachymeter

Answer

Keratometer

Answer

Tonometer

Question 6

What is the dye and filter used to diagnose corneal ulcers?

Accepted Answer

Fluorescein dye - visualized under cobalt blue filter

Answer

Lissamine green dye - visualized under green filter

Answer

Lissamine blue dye - visualized under cobalt blue filter

Answer

Fluorescein dye - visualized under green filter

Question 7

What is a characteristic finding in fungal corneal ulcers?

Accepted Answer

Satellite lesions

Answer

Dendritic ulcer

Answer

Ring abscess

Answer

White hypopyon

Question 8

A 30 year old man presents to the clinic with pain in the eye, watering, redness, and photophobia. Examination of his eyes shows circumcorneal congestion and keratic precipitates. Assertion: Keratic precipitates (KPs) are proteinaceous deposits that can occur in various patterns on the corneal endothelium. Reason: Mutton fat KPs are seen in granulomatous iridocyclitis and are composed of epithelioid cells and macrophages.

Accepted Answer

Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion

Answer

Both Assertion and Reason are true, and Reason is the correct explanation for Assertion

Answer

Assertion is true, but Reason is false

Answer

Assertion is false but reason is true

Question 9

All of the following are true about Keratoconus, except:

Accepted Answer

Thick cornea

Answer

Astigmatism

Answer

Increased curvature of cornea and Astigmatism

Answer

Fleischer's ring

Question 10

Unilateral frontal blisters with upper lid edema and conjunctivitis is seen in?

Accepted Answer

Herpes Zoster Ophthalmicus

Answer

Herpes Simplex

Answer

Neuroparalytic Keratitis

Answer

Acanthamoeba Keratitis

Diseases of the Cornea — MCQs

Diseases of the Cornea — MCQs

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