Diseases of the Cornea Practice Questions

Q: Identify the stain instilled in the eye in the following image:

Fluorescein stain. ***Fluorescein stain*** - The image shows a **green-yellow fluorescence** under cobalt blue light, which is characteristic of **fluorescein dye** pooling in areas of epithelial defect or healthy tear film. - Fluorescein is a commonly used diagnostic dye in ophthalmology to visualize **corneal abrasions**, ulcers, or contact lens-related issues as it stains damaged corneal epithelial cells. *Rose Bengal stain* - **Rose Bengal** stains devitalized epithelial cells and mucus a **red or purple color**, not green or yellow. - It is particularly useful for identifying **dry eye syndrome** and herpes simplex keratitis but would appear distinctly different from the image. *Lissamine green stain* - **Lissamine green** stains damaged or devitalized conjunctival and corneal cells a **blue-green color**, similar to Rose Bengal. - While it has a greenish hue, it typically does not fluoresce and produces a distinct staining pattern different from the bright, uniform green seen with fluorescein under blue light. *Rhodamine stain* - **Rhodamine** dyes, which are typically **red or pink fluorescent**, are not routinely used as a standard ophthalmic stain for general corneal evaluation. - Its spectral properties and clinical applications are distinct from the common diagnostic dyes used on the ocular surface.

Q: Which of the following is correct about the image shown? (Recent NEET Pattern 2016-17)

A = Kayser Fleischer ring, B = Arcus senilis. ***A = Kayser Fleischer ring, B = Arcus senilis*** - Image A displays a **Kayser-Fleischer ring**, a greenish-brown ring in the periphery of the cornea, characteristic of **Wilson's disease** due to copper deposition. - Image B shows **arcus senilis**, a milky-white or grayish ring around the cornea, which is a **common age-related change** due to lipid deposits, and can appear at any age. *A = Arcus senilis, B = Kayser-Fleischer ring* - This option incorrectly identifies the lesions; the ring in image A is associated with copper deposition, not lipid deposition. - The ring in image B is clearly a common lipid ring often seen in older individuals, contrasting with the distinct appearance of a Kayser-Fleischer ring. *A = Arcus senilis, B = Hudson-Stahli line* - Image A does not show arcus senilis; its color and location are consistent with copper deposition. - Image B does not depict a Hudson-Stahli line, which is a thin, brownish-linear deposit of iron in the corneal epithelium, typically horizontal and not circumferential. *A = Hudson-Stahli line, B = Arcus senilis* - Image A's appearance, as a circumferential greenish-brown deposit, is not consistent with a linear Hudson-Stahli line. - While image B correctly identifies arcus senilis, the identification of A as a Hudson-Stahli line is incorrect.

Q: A patient presents to the OPD with the finding shown in the image. What is the most likely diagnosis?

Limbal dermoid. ***Limbal dermoid*** - A **limbal dermoid** is a congenital benign tumor typically found at the **limbus**, the junction between the cornea and sclera. - It appears as a **raised, yellowish-white mass** and may contain elements like hair follicles or sebaceous glands. *Pyogenic granuloma* - A **pyogenic granuloma** is a rapidly growing, benign vascular lesion that typically occurs after trauma or surgery. - It presents as a **red, pedunculated nodule** that bleeds easily, unlike the described finding. *Papilloma* - **Papillomas** are benign epithelial tumors caused by the human papillomavirus (HPV). - They appear as **small, fleshy growths** with a cauliflower-like surface and are less common at the limbus. *Pinguecula* - A **pinguecula** is a common, benign yellowish growth on the conjunctiva, usually located on the nasal side of the cornea. - It does not typically involve the **cornea** or appear as a raised mass like a dermoid tumor.

Q: Which of the following is not a feature of keratoconus?

Haab's striae. ***Haab's striae*** - **Haab's striae** are characteristic of congenital glaucoma, presenting as horizontal breaks in Descemet's membrane due to increased intraocular pressure and corneal stretching. - In contrast, keratoconus involves **vertical breaks in Descemet's membrane** (due to corneal thinning and protrusion), known as Vautin's striae or Vogt's striae, not Haab's striae. *Irregular astigmatism* - **Irregular astigmatism** is a hallmark of keratoconus, resulting from the asymmetric and non-uniform thinning and protrusion of the cornea. - This irregular corneal shape leads to a significant reduction in visual acuity that cannot be fully corrected with spherical or regular cylindrical lenses. *Scissoring reflex* - The **scissoring reflex** (or scissoring phenomena) is an objective finding observed during retinoscopy in patients with keratoconus, indicating significant irregular astigmatism. - It refers to the opposing movements of the retinoscopic reflex, resembling the opening and closing of scissors, as the light across the pupil is neutralized. *Munson's sign* - **Munson's sign** is a classic clinical finding in advanced keratoconus, where the lower eyelid protrudes in a V-shape when the patient looks downwards. - This protrusion is caused by the conical shape of the cornea pushing against the eyelid.

Q: Fleischer's ring is seen in?

Keratoconus. ***Keratoconus*** - **Fleischer's ring** is a brownish-yellow to greenish-brown ring of **iron deposition** (hemosiderin) in the **corneal epithelium** around the base of the cone in patients with **keratoconus**. - It is a specific sign of **keratoconus**, which is a progressive thinning and steepening of the cornea, causing it to bulge into a cone shape. *Keratoglobus* - **Keratoglobus** is a rare, non-inflammatory condition where the **entire cornea** becomes thin and globularly protrudes, unlike the localized cone in keratoconus. - It typically does not present with an isolated Fleischer's ring; other corneal findings may be present. *Keratomalacia* - **Keratomalacia** is corneal softening and necrosis caused by severe **vitamin A deficiency**. - It presents with xerosis (dryness), night blindness, and eventual corneal melting and perforation. - It does not involve iron deposition in the form of a Fleischer's ring. *Trachoma* - **Trachoma** is a chronic infectious disease of the eye caused by *Chlamydia trachomatis*, leading to scarring of the conjunctiva and cornea. - It is a leading cause of preventable blindness worldwide and is not associated with Fleischer's ring.

Q: True about Mooren's ulcer:

Affects cornea. ***Affects cornea*** - **Mooren's ulcer** is a rare, severe, and idiopathic chronic **ulcerative keratitis** that primarily affects the cornea. - It involves a progressive **peripheral corneal stromal thinning** and ulceration, often extending circumferentially and centrally. *Bilateral in majority of cases* - Mooren's ulcer is **unilateral in approximately 60-80%** of cases, making bilateral presentation less common. - While it can be bilateral, especially in a more severe form, it's not the majority presentation. *Sudden loss of vision* - The vision loss associated with Mooren's ulcer is typically **gradual and progressive**, due to increasing corneal thinning, scarring, and astigmatism. - **Sudden vision loss** is not a characteristic feature of this condition and would suggest other acute pathologies. *Painless* - Mooren's ulcer is often associated with **significant pain**, **photophobia**, and **lacrimation**. - The pain can be severe and debilitating, stemming from the inflammatory process and corneal nerve involvement.

Q: Cornea derives its nutrition chiefly from:

Aqueous humour. ***Aqueous humour*** - The cornea is **avascular**, meaning it lacks its own blood vessels, and thus relies on the **aqueous humor** for metabolic support. - The aqueous humor, located in the anterior chamber, provides **glucose, amino acids, and oxygen** to the posterior surface of the cornea. *Corneal vessels* - The **cornea is avascular** under normal physiological conditions; the presence of corneal vessels (neovascularization) is typically a sign of pathology. - This avascularity is crucial for maintaining corneal transparency and optimal vision. *Perilimbal vessels* - Perilimbal vessels (at the limbus, the junction between cornea and sclera) primarily supply the **periphery of the cornea** and the limbal stem cell niche, not the entire cornea's main nutritional needs. - While they contribute some oxygen and nutrients, the **aqueous humor** is the predominant source for the central and posterior cornea. *Mucous layer* - The mucous layer, part of the tear film, primarily functions in **lubrication and adhesion** of the tear film to the corneal surface. - While it contains some dissolved oxygen from the atmosphere to supply the anterior cornea, its role in nutrient supply (glucose, amino acids) is **minimal** compared to the aqueous humor.

Q: In uveitis, site of keratic precipitate is:

Corneal endothelium. ***Corneal endothelium*** - **Keratic precipitates (KPs)** are inflammatory cellular deposits that adhere to the **posterior surface of the cornea**, specifically the endothelial layer, in uveitis. - They represent aggregates of inflammatory cells, such as macrophages and lymphocytes, that have migrated from the inflamed anterior chamber. *Lens anterior capsule* - The **anterior capsule of the lens** is a smooth, acellular membrane and does not typically accumulate inflammatory deposits like **keratic precipitates**. - While inflammatory cells can be observed in the **anterior chamber**, they do not specifically adhere to the lens capsule in this manner. *Lens posterior capsule* - Similar to the anterior capsule, the **posterior capsule of the lens** is not the site for deposition of **keratic precipitates**. - Inflammation affecting the lens would typically present as cataract formation or direct lens inflammation, not KPs. *Corneal stroma* - The **corneal stroma** is the thickest layer of the cornea and is primarily composed of collagen fibrils and keratocytes. - While inflammation can affect the stroma (e.g., in stromal keratitis), **keratic precipitates** specifically form on the **innermost layer**, the endothelium, facing the anterior chamber.

Q: A 20-year-old male complains of repeated changes in glasses prescription. This is most likely caused by:

Keratoconus. ***Keratoconus*** - **Keratoconus** is a progressive disorder where the cornea thins and protrudes into a cone shape, leading to irregular astigmatism and frequent changes in glasses prescription. - This condition commonly presents in young adults and is characterized by **rapid, repeated changes** in both spherical and cylindrical components due to progressive corneal distortion. - The irregular corneal shape makes it difficult to achieve stable, satisfactory vision correction with glasses alone. *Cataract* - A **cataract** is a clouding of the eye's natural lens, which causes blurred vision, glare, and difficulty seeing at night. - While it can cause a "myopic shift" leading to prescription changes, it is more common in older individuals (>50 years) and the changes are typically slower and less frequent than in keratoconus. *Glaucoma* - **Glaucoma** is a group of eye conditions that damage the optic nerve, often due to high intraocular pressure, leading to peripheral vision loss and eventually blindness. - It does not cause changes in refractive error or require frequent updates to glasses prescriptions. - Visual changes are related to field defects, not refractive changes. *Pathological myopia* - **Pathological myopia** is a severe form of nearsightedness where the eye elongates excessively, leading to progressive increases in myopic refractive error. - While it can cause prescription changes in young adults, the progression is typically more **gradual and predictable** (mainly increasing spherical myopia) compared to the **rapid, irregular changes** seen in keratoconus. - Keratoconus is distinguished by frequent changes in astigmatism due to irregular corneal shape, whereas pathological myopia mainly affects spherical power.

Q: For transplantation, cornea can be removed from dead body up to:

24 hours. ***24 hours*** - Corneas can be harvested from a deceased donor within **24 hours** of death, provided the body is kept in a cool environment. - This time frame allows for adequate perfusion of the corneal tissue and maintains **cellular viability** for successful transplantation. *6 hours* - While some organs have a very limited window for retrieval, **corneas** generally have a longer viability compared to highly metabolic organs. - A 6-hour window is often too short and would significantly limit the availability of corneal tissue for transplantation. *18 hours* - An 18-hour window is a reasonable period but is often extended to 24 hours under proper storage conditions. - Extending to **24 hours** maximizes the opportunity for procurement and does not significantly compromise tissue quality for corneal transplantation. *12 hours* - A 12-hour window, although longer than 6 hours, is still a conservative estimate for corneal retrieval. - With advancements in preservation techniques, the **viability period** for corneas is now widely accepted to be up to 24 hours post-mortem.

Question 1

Identify the stain instilled in the eye in the following image:

Accepted Answer

Fluorescein stain

Answer

Rose Bengal stain

Answer

Lissamine green stain

Answer

Rhodamine stain

Question 2

Which of the following is correct about the image shown? (Recent NEET Pattern 2016-17)

Accepted Answer

A = Kayser Fleischer ring, B = Arcus senilis

Answer

A = Arcus senilis, B = Kayser-Fleischer ring

Answer

A = Arcus senilis, B = Hudson-Stahli line

Answer

A = Hudson-Stahli line, B = Arcus senilis

Question 3

A patient presents to the OPD with the finding shown in the image. What is the most likely diagnosis?

Accepted Answer

Limbal dermoid

Answer

Pyogenic granuloma

Answer

Papilloma

Answer

Pinguecula

Question 4

Which of the following is not a feature of keratoconus?

Accepted Answer

Haab's striae

Answer

Irregular astigmatism

Answer

Scissoring reflex

Answer

Munson's sign

Question 5

Fleischer's ring is seen in?

Accepted Answer

Keratoconus

Answer

Keratoglobus

Answer

Keratomalacia

Answer

Trachoma

Question 6

True about Mooren's ulcer:

Accepted Answer

Affects cornea

Answer

Bilateral in majority of cases

Answer

Sudden loss of vision

Answer

Painless

Question 7

Cornea derives its nutrition chiefly from:

Accepted Answer

Aqueous humour

Answer

Corneal vessels

Answer

Perilimbal vessels

Answer

Mucous layer

Question 8

In uveitis, site of keratic precipitate is:

Accepted Answer

Corneal endothelium

Answer

Lens anterior capsule

Answer

Lens posterior capsule

Answer

Corneal stroma

Question 9

A 20-year-old male complains of repeated changes in glasses prescription. This is most likely caused by:

Accepted Answer

Keratoconus

Answer

Cataract

Answer

Glaucoma

Answer

Pathological myopia

Question 10

For transplantation, cornea can be removed from dead body up to:

Accepted Answer

24 hours

Answer

6 hours

Answer

18 hours

Answer

12 hours

Diseases of the Cornea — MCQs

Diseases of the Cornea — MCQs

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