Diseases of the Cornea Practice Questions

Q: Treatment for dendritic ulcer includes all except:

Steroids. **Explanation:** Dendritic ulcers are the hallmark of **Herpes Simplex Keratitis (HSK)**, specifically the epithelial stage. The primary pathology is active viral replication within the corneal epithelial cells. **Why Steroids are Contraindicated (Correct Answer):** Topical steroids are strictly **contraindicated** in the presence of an active dendritic ulcer. Steroids suppress the local immune response and promote viral replication. This can lead to the expansion of the ulcer into a "geographic ulcer" and may facilitate stromal invasion or corneal perforation. **Analysis of Other Options:** * **Acyclovir (3% Ointment):** This is the standard antiviral treatment. It works by inhibiting viral DNA polymerase, thereby stopping replication. * **Debridement:** Mechanical debridement of the ulcer edges (which contain the highest load of live virus) helps reduce the viral load and allows for faster healing and better penetration of antiviral drugs. * **Penetrating Keratoplasty (PK):** While not the first-line treatment for an *active* ulcer, "therapeutic PK" may be indicated in cases of impending or actual corneal perforation resulting from complications of the ulcer. **NEET-PG High-Yield Pearls:** * **Morphology:** Dendritic ulcers have a linear, branching pattern with characteristic **terminal bulbs** (knobs) that stain with Fluorescein. The bed stains with Fluorescein, while the margins (containing virus) stain with **Rose Bengal**. * **Sensation:** Corneal sensations are typically **reduced or absent** (hypoesthesia) in HSK. * **Steroid Exception:** Steroids are only used in HSK for **Disciform Keratitis** (stromal involvement), which is an immune-mediated reaction, but *only* under the cover of topical antivirals.

Q: A patient presents to the OPD with a recent onset of photophobia within 24 hours and a sloughing corneal ulcer. There is a greenish ulcer base. Which of the following can be the causative organism?

Pseudomonas. **Explanation:** The clinical presentation of a rapidly progressing, sloughing corneal ulcer with a characteristic **greenish-yellow discharge** or base is a classic hallmark of **Pseudomonas aeruginosa** keratitis. **1. Why Pseudomonas is correct:** Pseudomonas is a Gram-negative aerobe known for its high virulence. It produces enzymes like **proteases and elastases** that cause rapid liquefactive necrosis of the corneal stroma (sloughing). The distinctive greenish hue is due to the production of pigments, primarily **pyocyanin**. It is the most common cause of corneal ulcers in contact lens wearers and can lead to corneal perforation within 24–48 hours if not treated aggressively. **2. Why other options are incorrect:** * **Acanthamoeba:** Typically presents with a **ring-shaped infiltrate** and pain out of proportion to clinical findings. It has a much more chronic, indolent course compared to the rapid onset described here. * **Nocardia:** Usually presents with a "wreath-like" or **patchy infiltrate** and is often associated with trauma involving soil or post-LASIK infections. It does not produce a greenish slough. * **Herpes (HSV):** Characterized by **dendritic ulcers** (with terminal bulbs) and decreased corneal sensations. It does not cause a purulent, sloughing greenish ulcer. **Clinical Pearls for NEET-PG:** * **Pseudomonas:** Rapidly spreading, greenish discharge, common in contact lens users. * **Staphylococcus aureus:** Localized, round/oval ulcer with clear margins. * **Streptococcus pneumoniae:** Often associated with chronic dacryocystitis; causes a "hypopyon ulcer" (Ulcus Serpens). * **Fungal Keratitis:** Feathery margins, satellite lesions, and a dry, leathery appearance.

Q: A patient presents with a painless ulcer in the eye. On examination, a long, branching ulcer with desquamated epithelium is seen on the cornea. What is the most likely diagnosis?

Neurotrophic ulcer. ***Neurotrophic ulcer***- The defining feature of a **neurotrophic ulcer** is the **painless** nature of the epithelial defect, resulting from damage to the **trigeminal nerve** (CN V1) leading to loss of corneal sensation.- The ulcer morphology, described as a persistent epithelial defect (ulcer) with a desquamated, **geographic** or long-branching appearance, is characteristic of the poor healing seen in the setting of chronic denervation.*Fungal ulcer*- Fungal ulcers typically cause marked pain, photophobia, and conjunctival injection, which contrasts sharply with the painless presentation in this patient.- Morphologically, they are often characterized by elevated, gray-white ulcers with **feathery borders** and commonly exhibit satellite lesions or an underlying **immune ring**.*Dendritic ulcer*- A **dendritic ulcer** is pathognomonic for **Herpes Simplex Virus (HSV) keratitis** and is usually associated with significant pain and foreign body sensation.- While it is branching, it stains vividly, and its key features are **terminal bulbs** at the ends of the branches, differentiating it from the desquamated, geographic type of defect seen in neurotrophic disease.*Bacterial corneal ulcer*- Bacterial corneal ulcers are extremely painful, rapidly progressive, and associated with profound inflammation, ciliary injection, and often significant **anterior chamber reaction (hypopyon)**.- They usually present as dense, whitish-yellow **stromal infiltrates** with an overlying epithelial defect, not a painless, superficially desquamated pattern.

Q: Which condition is treated using an Intacs ring, as shown in the image?

Keratoconus. ***Keratoconus*** - The image displays **Intacs**, which are intracorneal ring segments specifically designed to treat **keratoconus** by flattening the steep cornea. - This procedure provides structural support to the weakened, cone-shaped cornea, thereby improving uncorrected and best-corrected visual acuity by reducing **myopia** and **astigmatism**. *Cataract* - Cataract treatment involves the surgical removal of the opacified natural lens, typically through **phacoemulsification**. - An **intraocular lens (IOL)** is implanted in place of the natural lens, not a ring within the corneal stroma as shown. *Corneal ulcer* - A corneal ulcer is an active infection of the cornea and is treated primarily with intensive **topical antimicrobial** therapy (antibiotics, antifungals, or antivirals). - Placing a foreign body like an Intacs ring is contraindicated in an active infection and would worsen the condition. *Glaucoma* - The goal of glaucoma treatment is to lower **intraocular pressure (IOP)** to prevent optic nerve damage. - This is managed with medications (eye drops), **laser procedures** (e.g., trabeculoplasty), or **filtration surgery** (e.g., trabeculectomy), none of which involve corneal ring implants.

Q: A patient presents with guttate lesions in one eye and bullous keratopathy in the other eye. What is the most likely diagnosis?

Fuchs' endothelial dystrophy. ***Fuchs' endothelial dystrophy*** - This condition involves progressive loss of corneal endothelial cells and deposition of abnormal basement membrane material (**guttae**). The presence of **guttate lesions** represents early disease. - As the disease progresses and the remaining endothelial cells fail to pump fluid effectively, the cornea swells, leading to epithelial and stromal edema, clinically described as **bullous keratopathy**. *Interstitial keratitis* - This is non-ulcerative inflammation predominantly affecting the **corneal stroma**, often associated with systemic infections like **congenital syphilis** or Cogan's syndrome. - It typically causes stromal clouding and deep **neovascularization** (ghost vessels) but does not primarily involve guttate lesions or asymmetric endothelial failure. *Viral corneal ulcer* - Viral ulcers (like those caused by **HSV**) present acutely with epithelial defects, often in a dendritic or geographic pattern, and cause significant inflammation. - They are acute processes characterized by surface epithelial involvement, not characterized by the slowly progressive, **endothelial-based changes** (guttae and bullae) seen in Fuchs' dystrophy. *Keratoconjunctivitis* - This is a general term for inflammation affecting both the cornea and conjunctiva, commonly seen in **adenoviral infections** or severe dry eye (**KCS**). - The primary findings are typically conjunctival injection and punctate epithelial erosions, not the specific endothelial deposits (**guttae**) or resulting severe edema (**bullous keratopathy**) characteristic of Fuchs' dystrophy.

Q: A child from slums presents with cheese like lesion on temporal side of Cornea. What is the diagnosis?

Keratomalacia. ***Keratomalacia*** - The appearance of **"cheese-like" lesions** on the cornea, especially on the **temporal side**, in a child from underprivileged settings suggests **corneal melting due to severe vitamin A deficiency**, characteristic of keratomalacia. - This condition is typically associated with **malnutrition** and can lead to irreversible blindness if not treated promptly with **vitamin A supplementation**. *Phlyctenular keratoconjunctivitis* - This condition is characterized by **nodular lesions (phlyctenules)** on the cornea or conjunctiva, often seen in children with a **hypersensitivity reaction** to microbial antigens like tuberculosis. - Phlyctenules typically appear as small, white, elevated lesions, but are not described as "cheese-like" and their typical location and appearance differ from the image shown. *Corneal ulcer* - A corneal ulcer is an **open sore** on the cornea that can be caused by infection (bacterial, viral, fungal, protozoal) or trauma. - While it can appear whitish due to corneal infiltration, a "cheese-like" appearance specifically on the temporal side in a malnourished child points more directly to keratomalacia. *Pterygium* - A pterygium is a **fleshy, triangular growth** of conjunctival tissue that extends onto the cornea, typically from the nasal side, and is associated with **UV light exposure**. - Its appearance is distinct from the diffuse, cheesy lesion seen in the image, and it is less common in young children.

Q: The procedure being performed in the image is:

Fluorescein staining with cobalt blue light. ***Fluorescein staining with cobalt blue light*** - The image shows a bright **fluorescent green** color on the surface of the eye, which is characteristic of **fluorescein dye** being illuminated by a **cobalt blue light** - This technique is used to detect **epithelial defects** or **abrasions** on the cornea or conjunctiva, as the dye adheres to areas where cells are damaged - Fluorescein is a **water-soluble** dye that stains areas where the **epithelial barrier is breached** - Essential for diagnosing **corneal ulcers**, **abrasions**, and **foreign body tracks** *Rose Bengal staining* - Rose Bengal is another vital dye used to stain **dead or degenerating cells** on the ocular surface - Stains areas of **poor mucin coverage** and is useful in diagnosing **dry eye syndrome** - Does NOT produce the characteristic **bright green fluorescence** seen with fluorescein under cobalt blue light *Schirmer's test* - This test is used to measure **tear production**, not to visualize epithelial defects - Involves placing a **filter paper strip** in the lower eyelid and measuring tear wetting - Used in diagnosis of **dry eye syndrome** and **keratoconjunctivitis sicca** *Slit lamp examination* - A general examination technique using a **biomicroscope** to examine anterior segment structures - Does not involve the use of dyes or produce the **fluorescent green** appearance - While fluorescein staining can be viewed with a slit lamp using a cobalt blue filter, the procedure shown specifically refers to the **staining technique** itself

Q: The following appearance of eye is seen in:

Wilson's disease. ***Wilson's disease (Correct)*** - The image shows a **Kayser-Fleischer ring**, a greenish-brown or golden-brown pigment ring in the peripheral cornea (Descemet's membrane), which is **pathognomonic for Wilson's disease** - Wilson's disease is an **autosomal recessive** disorder of copper metabolism (mutation in ATP7B gene), leading to copper accumulation in various tissues, including the cornea, liver, and basal ganglia - **Slit-lamp examination** is required for optimal visualization of the ring *Arcus senilis (Incorrect)* - This is a **grayish-white lipid** deposition in the peripheral cornea, common in elderly patients - It has a **clear zone** (lucid interval) between the ring and the limbus, unlike Kayser-Fleischer ring which extends to the limbus - Not pathological in elderly but may indicate hyperlipidemia in younger patients *Band keratopathy (Incorrect)* - This appears as **calcium deposition** in a horizontal band across the central cornea in the interpalpebral fissure - Associated with **chronic uveitis, hypercalcemia**, or chronic ocular surface disease - Has a characteristic **Swiss cheese appearance** with clear holes *Corneal foreign body (Incorrect)* - Would present as a **localized opacity or infiltrate**, not a circumferential ring - Associated with **history of trauma** and unilateral presentation - May have surrounding inflammation or rust ring if metallic

Q: Which is correct about the image shown below?

Radial keratoneuritis. ***Radial keratoneuritis*** - The image exhibits **radial, spoke-like opacities** in the cornea, which are characteristic of radial keratoneuritis. - This condition is associated with viral infections, particularly **herpes simplex virus (HSV)** and **varicella-zoster virus (VZV)**, causing inflammation along corneal nerves. - The spoke-like pattern represents corneal nerve inflammation with surrounding stromal infiltrates. *Keratoplasty* - **Keratoplasty** (corneal transplant) involves surgically replacing damaged corneal tissue with donor tissue. - While post-operative cases may show suture marks or graft-related changes, the radial spoke-like pattern of corneal opacities is not typical of keratoplasty. *Iridocyclitis* - **Iridocyclitis** is inflammation of the iris and ciliary body (anterior uveitis). - Primary signs include **ciliary flush**, **aqueous flare**, **cells in anterior chamber**, and **keratic precipitates** on the corneal endothelium. - The radial corneal stromal opacities seen in this image are not characteristic of iridocyclitis. *Vertical fixed pupil* - A **vertical fixed pupil** refers to an abnormally shaped pupil that is vertically elongated and non-reactive to light. - The pupil in the image appears round and normal, without vertical elongation or fixation. - This finding is unrelated to the corneal pathology shown.

Question 1

Treatment for dendritic ulcer includes all except:

Accepted Answer

Steroids

Answer

Penetrating keratoplasty

Answer

Acyclovir

Answer

Debridement of the edges of the ulcer

Question 2

A patient presents to the OPD with a recent onset of photophobia within 24 hours and a sloughing corneal ulcer. There is a greenish ulcer base. Which of the following can be the causative organism?

Accepted Answer

Pseudomonas

Answer

Acanthamoeba

Answer

Nocardia

Answer

Herpes

Question 3

A patient presents with a painless ulcer in the eye. On examination, a long, branching ulcer with desquamated epithelium is seen on the cornea. What is the most likely diagnosis?

Accepted Answer

Neurotrophic ulcer

Answer

Bacterial corneal ulcer

Answer

Fungal ulcer

Answer

Dendritic ulcer

Question 4

Following a fungal corneal ulcer, a farmer underwent corneal transplant surgery. What is the preservative used for storing the donor corneal graft and the suture material used in the procedure?

Accepted Answer

McCarey-Kaufman, Nylon

Answer

Polyethylene glycol, Nylon

Answer

Moist chamber, Vicryl

Answer

Ethanol, Silk

Question 5

Which condition is treated using an Intacs ring, as shown in the image?

Accepted Answer

Keratoconus

Answer

Glaucoma

Answer

Cataract

Answer

Corneal ulcer

Question 6

A patient presents with guttate lesions in one eye and bullous keratopathy in the other eye. What is the most likely diagnosis?

Accepted Answer

Fuchs' endothelial dystrophy

Answer

Keratoconjunctivitis

Answer

Interstitial keratitis

Answer

Viral corneal ulcer

Question 7

A child from slums presents with cheese like lesion on temporal side of Cornea. What is the diagnosis?

Accepted Answer

Keratomalacia

Answer

Phlyctenular keratoconjunctivitis

Answer

Corneal ulcer

Answer

Pterygium

Question 8

The procedure being performed in the image is:

Accepted Answer

Fluorescein staining with cobalt blue light

Answer

Rose Bengal staining

Answer

Schirmer's test

Answer

Slit lamp examination

Question 9

The following appearance of eye is seen in:

Accepted Answer

Wilson's disease

Answer

Arcus senilis

Answer

Band keratopathy

Answer

Corneal foreign body

Question 10

Which is correct about the image shown below?

Accepted Answer

Radial keratoneuritis

Answer

Keratoplasty

Answer

Iridocyclitis

Answer

Vertical fixed pupil

Diseases of the Cornea — MCQs

Diseases of the Cornea — MCQs

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