Diseases of the Sclera Practice Questions

Q: Ciliary staphyloma is seen in which of the following conditions?

Absolute glaucoma. **Explanation:** **Ciliary staphyloma** is a localized thinning and bulging of the sclera lined by the underlying ciliary body. It occurs due to a combination of weakened scleral integrity and chronically elevated intraocular pressure (IOP). 1. **Why Absolute Glaucoma is correct:** In absolute glaucoma, the IOP is severely and chronically elevated. This persistent pressure causes the sclera to stretch and thin, particularly in the **ciliary zone** (the area 2–8 mm behind the limbus). As the sclera thins, the dark pigment of the underlying ciliary body shines through, giving it a characteristic bluish-black appearance. 2. **Why the other options are incorrect:** * **Pathological Myopia:** This is typically associated with **Posterior staphyloma**, where the thinning occurs at the posterior pole (macular area) due to excessive axial elongation. * **Retinoblastoma:** While advanced tumors can cause globe enlargement (buphthalmos) or extraocular extension, they do not typically present as a focal ciliary staphyloma. * **Episcleritis:** This is a self-limiting, superficial inflammation of the episcleral tissues that does not lead to scleral thinning or staphyloma formation. **Clinical Pearls for NEET-PG:** * **Types of Staphyloma:** * **Anterior (Intercalary):** At the limbus; seen in secondary glaucoma following corneal perforation. * **Ciliary:** 2–8 mm from limbus; seen in Absolute Glaucoma and Scleritis. * **Equatorial:** At the exit of vortex veins; seen in Pathological Myopia. * **Posterior:** At the posterior pole; hallmark of Pathological Myopia. * **Key Sign:** The "bluish" color of a staphyloma is not due to the sclera itself, but the **uveal tissue** visible through the thinned sclera.

Q: Which of the following is the MOST common type of staphyloma in myopia?

Posterior. **Explanation:** A **staphyloma** is a localized bulging of the weak outer tunic of the eyeball (sclera or cornea) lined by uveal tissue. The correct answer is **Posterior Staphyloma** because it is a hallmark clinical feature of **Pathological (Degenerative) Myopia**. * **Why Posterior is correct:** In high myopia, the anteroposterior diameter of the globe increases significantly. This stretching leads to thinning of the sclera at the posterior pole. As the sclera weakens, it bulges backward, lined by the choroid. It is most commonly seen at the macular area or around the optic nerve head. * **Why other options are incorrect:** * **Intercalary:** This occurs at the limbus (between the iris root and the ciliary body). It is usually a sequel to secondary glaucoma or perforating injuries, not myopia. * **Ciliary:** This occurs in the region of the ciliary body (about 2-8 mm behind the limbus). It is typically caused by scleritis or absolute glaucoma. * **Equatorial:** This occurs at the equator of the eye, where the sclera is perforated by the **vortex veins**. It is often associated with chronic glaucoma or scleromalacia. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Posterior staphyloma is best visualized using **B-scan ultrasonography** or Fundus Autofluorescence. * **Associations:** It is often associated with "Foster-Fuchs spots" (subretinal neovascularization) and "Lacquer cracks" (ruptures in Bruch’s membrane). * **Most Common Overall:** While Posterior is most common in myopia, **Anterior (Ciliary/Intercalary)** staphylomas are frequently associated with long-standing raised intraocular pressure (Glaucoma).

Q: What is an intercalary staphyloma?

A bulge in the limbal area lined by the root of the iris. **Explanation:** A **staphyloma** is a localized bulging of the outer coat of the eye (sclera or cornea) lined by uveal tissue. It occurs when the sclera thins due to inflammation or high intraocular pressure, allowing the underlying pigmented uvea to prolapse and appear as a bluish-black protrusion. **Intercalary staphyloma** specifically refers to a bulge in the **limbal area**, extending from the corneoscleral junction to about 2 mm posteriorly (the root of the iris). It is typically caused by secondary glaucoma or as a complication of scleritis. **Analysis of Options:** * **Option C (Correct):** By definition, an intercalary staphyloma occurs at the limbus and is lined by the **root of the iris**. * **Option A:** A sloughing corneal ulcer can lead to an **anterior staphyloma**, where the cornea is replaced by scarred pseudocornea lined by the iris. * **Option B:** Degenerative high myopia is the classic cause of a **posterior staphyloma**, which occurs at the posterior pole (macular area). * **Option D:** Penetrating injuries, if involving the ciliary body region, may lead to a **ciliary staphyloma** (located 2–8 mm behind the limbus). **High-Yield Facts for NEET-PG:** 1. **Types of Staphyloma:** * **Anterior:** Involves the cornea (post-perforation). * **Intercalary:** Limbus to 2mm; lined by iris root. * **Ciliary:** 2mm to 8mm; lined by ciliary body. * **Equatorial:** At the equator; lined by choroid (where vortex veins exit). * **Posterior:** At the posterior pole; associated with high myopia. 2. **Clinical Sign:** The characteristic **bluish-black color** is due to the underlying uveal tissue visible through the thinned sclera. 3. **Management:** Usually involves treating the underlying cause (e.g., controlling IOP) or surgical staphylectomy in advanced cases.

Q: Which clinical variety of scleritis is associated with collagen diseases?

All of the above. **Explanation:** Scleritis is a severe, vision-threatening inflammation of the sclera that is frequently associated with systemic autoimmune conditions (collagen vascular diseases) in approximately **30-50% of cases**. The most common association is **Rheumatoid Arthritis (RA)**, followed by Wegener’s Granulomatosis and Polyarteritis Nodosa (PAN). **Why "All of the above" is correct:** All clinical subtypes of anterior scleritis—whether necrotizing or non-necrotizing—can be the initial manifestation of an underlying collagen disease. * **Non-necrotizing Nodular Scleritis (Option B):** This is characterized by firm, immobile nodules. While often idiopathic, a significant portion of patients have underlying systemic inflammatory diseases. * **Necrotizing Nodular Scleritis (Option A):** This is a more severe form characterized by extreme pain and scleral thinning. It has a much higher correlation with systemic vasculitis and collagen diseases compared to non-necrotizing forms. * **Scleromalacia Perforans (Option C):** This is a specific type of **painless necrotizing scleritis** occurring almost exclusively in elderly women with long-standing **Rheumatoid Arthritis**. It leads to extreme scleral thinning, exposing the underlying uvea. **High-Yield Clinical Pearls for NEET-PG:** * **Most common systemic association:** Rheumatoid Arthritis (RA). * **Scleromalacia Perforans:** Key features are "Painless" and "RA association." * **Investigation of choice:** To rule out systemic involvement, order ESR, CRP, RF (Rheumatoid Factor), and c-ANCA. * **Treatment:** Unlike episcleritis (which responds to topical drops), scleritis requires **systemic NSAIDs, steroids, or immunosuppressants**. * **Phenylephrine Test:** Used to differentiate episcleritis from scleritis. In scleritis, the deep scleral vessels **do not blanch** with 10% phenylephrine.

Q: What is the commonest cause of posterior staphyloma?

High myopia. **Explanation:** **Posterior staphyloma** is defined as a localized bulging of the weak sclera lined by uveal tissue (choroid) at the posterior pole of the eye. **Why High Myopia is the Correct Answer:** High myopia (Pathological Myopia) is the **most common cause** of posterior staphyloma. In high myopia, the progressive elongation of the anteroposterior axis of the eyeball leads to excessive stretching and thinning of the posterior sclera. As the sclera weakens, it bulges outward, often involving the optic disc and macula. This is a hallmark feature of pathological myopia and is often associated with "lacquer cracks" and Forster-Fuchs spots. **Analysis of Incorrect Options:** * **A. Glaucoma:** While chronic high intraocular pressure can cause scleral stretching in children (Buphthalmos), it typically leads to **intercalary or ciliary staphyloma** in adults, rather than posterior staphyloma. * **B. Retinal Detachment:** This is often a *complication* of high myopia and posterior staphyloma, but it is not the causative mechanism for the staphyloma itself. * **C. Iridocyclitis:** This is an inflammation of the anterior uvea. While severe scleritis can lead to scleral thinning, it is not a primary cause of the classic posterior staphyloma seen in clinical practice. **NEET-PG High-Yield Pearls:** * **Types of Staphyloma:** 1. **Intercalary:** At the limbus (root of iris). 2. **Ciliary:** Over the ciliary body (2–8 mm behind limbus). 3. **Equatorial:** At the exit of vortex veins. 4. **Posterior:** At the posterior pole (associated with High Myopia). * **Diagnosis:** Posterior staphyloma is best visualized using **B-scan Ultrasonography** or Optical Coherence Tomography (OCT). * **Key Association:** It is one of the "Hallmark" signs of Pathological Myopia (defined as refractive error > -6D or axial length > 26.5mm).

Question 1

Ciliary staphyloma is seen in which of the following conditions?

Accepted Answer

Absolute glaucoma

Answer

Pathological myopia

Answer

Retinoblastoma

Answer

Episcleritis

Question 2

Which of the following is the MOST common type of staphyloma in myopia?

Accepted Answer

Posterior

Answer

Intercalary

Answer

Equatorial

Answer

Ciliary

Question 3

What is an intercalary staphyloma?

Accepted Answer

A bulge in the limbal area lined by the root of the iris

Answer

Sloughing corneal ulcer

Answer

Degenerative high myopia

Answer

Penetrating injuries

Question 4

Which clinical variety of scleritis is associated with collagen diseases?

Accepted Answer

All of the above

Answer

Necrotizing nodular scleritis

Answer

Non-necrotizing nodular scleritis

Answer

Scleromalacia perforans

Question 5

What is the commonest cause of posterior staphyloma?

Accepted Answer

High myopia

Answer

Glaucoma

Answer

Retinal detachment

Answer

Iridocyclitis

Diseases of the Sclera — MCQs

Diseases of the Sclera — MCQs

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