Diseases of the Sclera — MCQs

Diseases of the Sclera Indian Medical PG Practice Questions and MCQs

Question 11: Scleritis is associated with connective tissue disorders in what percentage of cases?

A. 35% of cases
B. 50% of cases (Correct Answer)
C. 66% of cases
D. 85% of cases

Explanation: **Explanation:** Scleritis is a severe, vision-threatening inflammation of the sclera that is frequently the first clinical manifestation of an underlying systemic autoimmune disease. **Why 50% is the correct answer:** Statistically, approximately **50% of patients** presenting with scleritis have an associated systemic disease. Among these, **connective tissue disorders (CTDs)** are the most common. Rheumatoid Arthritis (RA) is the leading systemic association, followed by Wegener’s Granulomatosis (GPA), Systemic Lupus Erythematosus (SLE), and Polyarteritis Nodosa (PAN). The inflammation in scleritis is often immune-mediated (Type III and Type IV hypersensitivity), reflecting the systemic vasculitic process occurring elsewhere in the body. **Analysis of Incorrect Options:** * **A (35%):** This underrepresents the clinical reality. While some older studies cited lower figures, modern diagnostic criteria and systemic workups consistently show a 1:2 ratio (50%) of systemic association. * **C & D (66% and 85%):** These figures are too high for general scleritis. While the association might be higher in specific subtypes (like necrotizing scleritis), for scleritis as a whole, the established high-yield figure for exams is 50%. **High-Yield Clinical Pearls for NEET-PG:** * **Most common association:** Rheumatoid Arthritis (RA). * **Most severe form:** Necrotizing scleritis with inflammation (often associated with lethal systemic vasculitis). * **Scleromalacia Perforans:** A specific type of necrotizing scleritis *without* inflammation, typically seen in elderly women with long-standing RA. * **Key Distinction:** Unlike episcleritis (which is usually idiopathic and self-limiting), scleritis is painful, involves deeper vessels that do not blanch with 10% phenylephrine, and requires systemic immunosuppression.

Question 12: In scleritis, all of the following are true EXCEPT:

A. Scleromalacia perforans are more commonly associated with systemic diseases than posterior scleritis.
B. Pain is not a prominent feature. (Correct Answer)
C. Retinal detachment is a known complication.
D. Glaucoma is a known complication.

Explanation: **Explanation:** Scleritis is a severe, vision-threatening inflammatory condition of the sclera, often associated with systemic autoimmune diseases (e.g., Rheumatoid Arthritis). **Why Option B is the correct answer (The "Except"):** Pain is the **hallmark feature** of scleritis. It is typically described as a severe, deep, boring ache that radiates to the forehead, jaw, or temple. It often worsens at night and with eye movements. The absence of pain is characteristic of episcleritis or the specific subtype "Scleromalacia Perforans," but for scleritis as a general entity, pain is a prominent and diagnostic feature. **Analysis of other options:** * **Option A:** Scleromalacia perforans (necrotizing scleritis without inflammation) is almost always associated with long-standing Rheumatoid Arthritis. While posterior scleritis can be associated with systemic disease, it is more frequently idiopathic compared to the necrotizing varieties. * **Option C:** Posterior scleritis can lead to exudative retinal detachment due to the extension of inflammation to the choroid and subretinal space. * **Option D:** Secondary glaucoma is a common complication of scleritis, resulting from trabeculitis, peripheral anterior synechiae, or ciliary body edema (angle-closure). **High-Yield Clinical Pearls for NEET-PG:** * **Phenylephrine Test:** Used to differentiate episcleritis from scleritis. In episcleritis, the congested vessels blanch; in scleritis, they do **not** blanch. * **Scleromalacia Perforans:** A unique form of necrotizing scleritis that occurs in elderly women with RA; it is characteristically **painless**. * **B-Scan Ultrasound:** The investigation of choice for Posterior Scleritis, showing the classic **"T-sign"** (fluid in Tenon’s space and optic nerve sheath).

Question 13: Which type of collagen is absent in the sclera?

A. Collagen 1
B. Collagen 2 (Correct Answer)
C. Collagen 3
D. Collagen 4

Explanation: **Explanation:** The sclera is the opaque, fibrous outer layer of the eye, primarily composed of dense connective tissue. Its main function is to maintain the shape of the globe and provide resistance to intraocular pressure. **Why Collagen Type II is the correct answer:** Collagen Type II is characteristic of **hyaline cartilage** and the **vitreous humor**. It is specifically adapted to resist compression. Since the sclera is a fibrous tissue designed to resist tensile stress rather than compression, it does not contain Type II collagen. **Analysis of Incorrect Options:** * **Collagen Type I (Option A):** This is the most abundant collagen in the sclera (approx. 80–90%). It provides the structural integrity and tensile strength necessary for the globe. * **Collagen Type III (Option C):** This is found in the sclera in smaller amounts (approx. 5–10%). It is often associated with wound healing and is found in the thin fibers of the lamina fusca. * **Collagen Type IV (Option D):** This is a key component of basement membranes. In the sclera, it is present in the basement membranes of the episcleral and intrascleral blood vessels. **High-Yield Clinical Pearls for NEET-PG:** * **Scleral Thickness:** It is thickest posteriorly at the posterior pole (1.0 mm) and thinnest at the insertion of the rectus muscles (0.3 mm)—this is the most common site for rupture in blunt trauma. * **Blue Sclera:** Occurs due to thinning of the scleral collagen, allowing the underlying uveal pigment to show through. Classically seen in **Osteogenesis Imperfecta**, Ehlers-Danlos syndrome, and Buphthalmos. * **Scleral Rigidity:** Increased in the elderly and decreased in high myopes.

Question 14: All of the following are features of episcleritis EXCEPT?

A. Redness
B. Marked pain (Correct Answer)
C. Photophobia
D. Lacrimation

Explanation: **Explanation:** The correct answer is **B. Marked pain**. Episcleritis is a benign, self-limiting inflammation of the episclera (the vascular tissue between the conjunctiva and the sclera). The hallmark of episcleritis is that it is **painless** or associated with only a mild, dull ache or gritty sensation. In contrast, **marked (severe) pain** is the cardinal clinical feature of **Scleritis**, which helps clinicians differentiate between the two conditions. * **Redness (Option A):** This is the most common presenting sign. It can be sectoral (Simple Episcleritis) or localized to a nodule (Nodular Episcleritis). The redness is due to engorgement of the superficial episcleral vessels. * **Photophobia and Lacrimation (Options C & D):** These are common, albeit mild, symptoms of ocular surface irritation. While not as prominent as in keratitis or uveitis, they frequently accompany the inflammatory process in episcleritis. **NEET-PG High-Yield Pearls:** 1. **Phenylephrine Test:** This is the gold standard for differentiation. Topical 10% Phenylephrine causes blanching (whitening) of the superficial episcleral vessels in **Episcleritis**, but fails to blanch the deep scleral vessels in **Scleritis**. 2. **Associations:** Episcleritis is usually idiopathic but can be associated with systemic conditions like Rheumatoid Arthritis, Gout, or IBD (though less frequently than scleritis). 3. **Treatment:** Most cases resolve spontaneously within 1–2 weeks. Topical NSAIDs or mild steroids are used for symptomatic relief. 4. **Scleritis Warning:** If a patient presents with "boring" pain that awakens them at night and radiates to the temple/jaw, suspect Scleritis.

Question 15: Which of the following is NOT true regarding nodular episcleritis?

A. Presents as a pink nodule
B. Is typically self-limiting
C. Can be recurrent
D. Requires aggressive treatment (Correct Answer)

Explanation: **Explanation:** **Nodular episcleritis** is a common, benign, and inflammatory condition affecting the episcleral tissues. Understanding its clinical course is essential for differentiating it from the more severe scleritis. **Why Option D is the correct answer:** Nodular episcleritis is generally a **mild, self-limiting condition**. Most cases resolve spontaneously within 2–3 weeks or require only conservative management (e.g., lubricants or mild topical NSAIDs/steroids). Unlike scleritis, it does **not** require aggressive systemic immunosuppression or intensive therapy, making Option D the false statement. **Analysis of Incorrect Options:** * **Option A (Pink nodule):** This is a classic clinical feature. It presents as a localized, firm, mobile, pinkish-red nodule, usually within the palpebral aperture. * **Option B (Self-limiting):** Most episodes are transient and resolve without leaving any permanent ocular damage or thinning of the sclera. * **Option C (Recurrent):** Recurrence is a hallmark of episcleritis. Patients often experience multiple episodes over several years, sometimes affecting different locations in the same or the fellow eye. **High-Yield Clinical Pearls for NEET-PG:** * **Phenylephrine Test:** This is the gold standard for differentiation. In episcleritis, the engorged superficial vessels **blanch (whiten)** after applying 10% Phenylephrine drops. In scleritis, the deep vascular plexus does not blanch. * **Mobility:** The nodule in episcleritis is **mobile** over the underlying sclera, whereas a scleral nodule is fixed. * **Pain:** Episcleritis typically presents with mild discomfort or a "gritty" sensation, whereas scleritis presents with **boring, severe pain** that radiates to the temple and awakens the patient at night.

Question 16: What is the thinnest part of the sclera?

A. At the entrance of the optic nerve
B. Site of entrance of ciliary nerves
C. Corneoscleral junction
D. At the insertion of recti muscles (Correct Answer)

Explanation: The sclera is the opaque, fibrous outer layer of the eye, providing structural integrity and protection. Its thickness varies significantly across different anatomical regions, which is a high-yield concept for surgical and clinical ophthalmology. ### **Explanation of the Correct Answer** **D. At the insertion of recti muscles:** The sclera is thinnest at the point immediately posterior to the insertion of the extraocular recti muscles, measuring approximately **0.3 mm**. This makes this site particularly vulnerable to rupture during trauma or accidental perforation during squint surgeries (recession/resection). ### **Analysis of Incorrect Options** * **A. At the entrance of the optic nerve:** This is actually the **thickest** part of the sclera, measuring approximately **1.0 mm to 1.3 mm**. The fibers here merge with the dural sheath of the optic nerve. * **B. Site of entrance of ciliary nerves:** While the sclera contains "emissaria" (channels) for nerves and vessels (like the long and short ciliary nerves), these are focal points of potential weakness but do not represent the thinnest overall zone of the scleral coat. * **C. Corneoscleral junction (Limbus):** At the limbus, the sclera is approximately **0.8 mm** thick. It is thicker than the muscle insertion sites but thinner than the posterior pole. ### **High-Yield Clinical Pearls for NEET-PG** * **Thickest part:** Posterior pole/Optic nerve entrance (1.0 mm). * **Thinnest part:** Just posterior to the insertion of recti muscles (0.3 mm). * **Equator thickness:** Approximately 0.4 mm to 0.6 mm. * **Lamina Cribrosa:** The sieve-like portion of the sclera through which optic nerve fibers pass; it is a site of clinical importance in glaucoma. * **Scleral Rigidity:** Important for Schiotz tonometry; high rigidity can lead to falsely high intraocular pressure readings.

Question 17: Scleritis is most commonly associated with which of the following conditions?

A. Polyarteritis nodosa
B. Tuberculosis
C. Rheumatoid arthritis (Correct Answer)
D. Sarcoidosis

Explanation: **Explanation:** **Scleritis** is a severe, vision-threatening inflammatory condition of the sclera. It is highly associated with systemic immune-mediated diseases, which are present in approximately **30–50%** of patients. **Why Rheumatoid Arthritis (RA) is the correct answer:** Among all systemic associations, **Rheumatoid Arthritis** is the most common, accounting for nearly 10–15% of all scleritis cases. The underlying pathophysiology involves a Type III (immune-complex mediated) and Type IV (delayed-type) hypersensitivity reaction. In RA, the chronic inflammatory state leads to vasculitis of the deep episcleral plexus, which can progress to necrotizing scleritis (Scleromalacia perforans). **Analysis of Incorrect Options:** * **A. Polyarteritis nodosa (PAN):** While PAN is a classic cause of necrotizing scleritis, it is much rarer than RA in the general population and clinical practice. * **B. Tuberculosis:** This is an infectious cause of scleritis. While important in the Indian context, infectious etiologies are significantly less common than autoimmune causes. * **D. Sarcoidosis:** Sarcoidosis more typically presents with granulomatous uveitis or conjunctival nodules rather than primary scleritis. **High-Yield Clinical Pearls for NEET-PG:** * **Scleromalacia Perforans:** This is a specific type of necrotizing scleritis without inflammation, occurring characteristically in elderly women with long-standing Rheumatoid Arthritis. * **Pain:** The hallmark of scleritis is severe, "boring" pain that radiates to the forehead or jaw and worsens at night (unlike episcleritis, which is mild/painless). * **Phenylephrine Test:** 10% Phenylephrine blanches superficial episcleral vessels (Episcleritis) but **fails** to blanch the deep episcleral vessels involved in Scleritis. * **Investigation of Choice:** B-scan Ultrasonography is used to diagnose **Posterior Scleritis** (look for the "T-sign" due to fluid in Tenon’s space).

Question 18: Staphyloma involves which of the following structures?

A. Iris with conjunctiva
B. Conjunctiva with cornea
C. Choroid with retina
D. Iris with cornea (Correct Answer)

Explanation: **Explanation:** **Staphyloma** is defined as a localized bulging of the weak outer coat of the eyeball (sclera or cornea), lined by **uveal tissue**. The hallmark of a staphyloma is the thinning of the fibrous coat to the extent that the underlying pigmented uveal tissue shines through, giving it a bluish-black appearance. **Why Option D is Correct:** The question refers specifically to **Anterior Staphyloma**, which most commonly occurs as a sequel to a perforated corneal ulcer. When the cornea perforates, the **iris** prolapses and becomes plastered to the back of the necrotic **corneal** tissue (pseudocornea). Due to increased intraocular pressure or structural weakness, this cicatrized "iris-cornea" complex bulges forward. **Analysis of Incorrect Options:** * **Option A & B:** The conjunctiva is a mucous membrane and does not form the structural wall of the globe involved in staphyloma formation. * **Option C:** While the choroid and retina are involved in **Posterior Staphyloma** (common in pathological myopia), the retina is a neurosensory layer, not the primary lining tissue that defines the "staphyloma" bulge in the context of the anterior segment. **High-Yield Clinical Pearls for NEET-PG:** 1. **Types of Staphyloma:** * **Anterior (Corneal):** Iris + Cornea (Pseudocornea). * **Intercalary:** Located at the limbus (up to the ciliary body). * **Ciliary:** Involves the ciliary body region (2–8 mm behind the limbus). * **Equatorial:** At the exit of vortex veins. * **Posterior:** At the posterior pole (associated with High Myopia). 2. **Appearance:** Characteristically **bluish** in color due to the underlying uveal pigment. 3. **Commonest Cause:** For anterior types, it is usually a perforated corneal ulcer; for posterior types, it is Pathological Myopia.

Question 19: Physiological blue sclera is seen in?

A. Elderly
B. Pregnancy
C. Premature newborn (Correct Answer)
D. None of these

Explanation: **Explanation:** The color of the sclera is primarily determined by its thickness and the degree of hydration of its collagen fibers. In a **premature newborn**, the sclera is physiologically very thin and highly translucent. This allows the underlying dark pigment of the **uveal tissue** (choroid) to shine through, giving the sclera a characteristic bluish appearance. As the child grows, the sclera thickens and becomes more opaque, turning white. **Analysis of Options:** * **Elderly (Option A):** In old age, the sclera often undergoes fatty degeneration or deposition of calcium and lipids, which typically gives it a **yellowish** tint, not blue. * **Pregnancy (Option B):** Pregnancy does not significantly alter the structural thickness or translucency of the sclera; therefore, blue sclera is not a feature of gestation. **High-Yield Clinical Pearls for NEET-PG:** * **Pathological Blue Sclera:** While physiological in newborns, a blue sclera in older children/adults is a classic sign of **Osteogenesis Imperfecta** (Type 1). * **Differential Diagnosis:** Other conditions associated with blue sclera include **Ehlers-Danlos Syndrome**, **Marfan Syndrome**, **Pseudoxanthoma Elasticum**, and **Buphthalmos** (where the sclera thins due to stretching from high intraocular pressure). * **Alkaptonuria:** Note that this condition causes brownish-black pigmentation (Ochronosis) of the sclera, not blue. * **Iron Deficiency Anemia:** Can occasionally present with a bluish scleral hue due to thinning of the collagen matrix.

Question 20: Which of the following statements about scleritis is false?

A. It is an intensely painful condition.
B. It presents with a violet-blue discoloration.
C. It is associated with Systemic Lupus Erythematosus (SLE).
D. It is the most common ocular manifestation in Crohn's Disease. (Correct Answer)

Explanation: **Explanation:** The correct answer is **D**. While scleritis is associated with Inflammatory Bowel Disease (IBD), it is **not** the most common ocular manifestation. In both Crohn’s Disease and Ulcerative Colitis, **episcleritis** is the most frequent ocular complication. Scleritis is less common but more severe, often correlating with active systemic disease. **Analysis of Options:** * **Option A (Intensely painful):** This is a hallmark feature of scleritis. Unlike episcleritis, which causes mild discomfort or grittiness, scleritis involves deep, boring pain that often radiates to the temple or jaw and frequently awakens the patient at night. * **Option B (Violet-blue discoloration):** Scleritis involves the deep episcleral vascular plexus. These vessels are large, non-blanching with phenylephrine, and give the eye a characteristic bluish-red or violaceous hue, especially visible in natural daylight. * **Option C (Associated with SLE):** Approximately 30-50% of scleritis cases are associated with systemic autoimmune diseases. While **Rheumatoid Arthritis** is the most common association, SLE, Granulomatosis with polyangiitis (GPA), and Polyarteritis Nodosa (PAN) are also significant causes. **High-Yield Clinical Pearls for NEET-PG:** * **Phenylephrine Test:** Used to differentiate episcleritis from scleritis. 10% Phenylephrine blanches superficial vessels (Episcleritis) but fails to blanch deep vessels (Scleritis). * **Necrotizing Scleritis with Inflammation:** The most severe form; can lead to **Scleromalacia Perforans** (painless thinning) when seen in long-standing Rheumatoid Arthritis. * **Investigation of Choice:** B-Scan Ultrasonography is used to diagnose **Posterior Scleritis**, showing the characteristic **"T-sign"** (fluid in Tenon’s space).

Practice by Chapter

Anatomy and Physiology of Sclera

Practice Questions

Episcleritis

Practice Questions

Scleritis: Anterior

Practice Questions

Scleritis: Posterior

Practice Questions

Infectious Scleritis

Practice Questions

Scleral Manifestations of Systemic Disease

Practice Questions

Blue Sclera Syndromes

Practice Questions

Scleral Degenerations

Practice Questions

Scleral Trauma

Practice Questions

Scleral Surgeries

Practice Questions

Necrotizing Scleritis

Practice Questions

Staphyloma

Practice Questions

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