Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva Indian Medical PG Practice Questions and MCQs

Question 71: Visual impairment in pterygium is primarily due to which refractive error?

A. Astigmatism (Correct Answer)
B. Myopia
C. Hypermetropia
D. Hazy cornea

Explanation: **Explanation:** The primary cause of visual impairment in a patient with pterygium is **Astigmatism**. **1. Why Astigmatism is the correct answer:** A pterygium is a triangular, fibrovascular proliferation of the subconjunctival tissue that grows onto the cornea. As it advances, it exerts mechanical traction on the corneal surface. This traction causes **flattening of the horizontal meridian** of the cornea, leading to **With-the-Rule (WTR) astigmatism**. Additionally, the pooling of tears at the leading edge (apex) of the pterygium can further alter the tear film and corneal curvature, contributing to irregular astigmatism. **2. Why the other options are incorrect:** * **Myopia & Hypermetropia:** These are axial or refractive errors primarily related to the length of the eyeball or the overall power of the lens/cornea. Pterygium specifically distorts the corneal contour rather than changing the axial length or spherical power. * **Hazy Cornea:** While a very large pterygium can cause opacification if it reaches the pupillary area (central visual axis), the *initial* and most common cause of decreased visual acuity is the refractive change (astigmatism) induced by the growth long before it obscures the center of the cornea. **Clinical Pearls for NEET-PG:** * **Stockers Line:** An iron deposition line seen on the corneal epithelium at the leading edge of a pterygium (indicates stability). * **Surgical Indication:** Surgery is indicated if the pterygium is progressive, causing significant astigmatism, or threatening the visual axis. * **Gold Standard Treatment:** Surgical excision with **Limbal Conjunctival Autograft (CAG)** is the preferred method to minimize the high recurrence rate. * **Fuchs' Striae:** Small whitish patches seen at the head of the pterygium.

Question 72: Which of the following conditions are caused by trachoma?

A. Entropion, corneal opacity, and dry eye
B. Entropion, corneal opacity, and ectropion (Correct Answer)
C. Entropion, ectropion, and corneal opacity
D. Entropion and corneal opacity

Explanation: ### Explanation **Trachoma**, caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C), is a leading cause of preventable blindness worldwide. The pathophysiology involves chronic follicular conjunctivitis leading to significant conjunctival scarring (**Arlt’s line**). **Why Option B is Correct:** The hallmark of cicatricial (late-stage) trachoma is the contraction of the conjunctival scar tissue. 1. **Entropion:** Scarring of the palpebral conjunctiva causes the eyelid margin to turn inward. 2. **Corneal Opacity:** This results from chronic irritation by misdirected lashes (**trichiasis**) and secondary bacterial infections, leading to ulceration and scarring. 3. **Ectropion:** While entropion is more common, **cicatricial ectropion** can also occur if the scarring involves the skin or external lamella of the lids, causing the lid margin to turn outward. **Analysis of Incorrect Options:** * **Option A:** While **Dry Eye** (Xerophthalmia) is a complication of trachoma due to the destruction of goblet cells and lacrimal ductules, Option B is the more traditional "textbook" triad of structural deformities often tested in this specific question format. * **Option C:** This repeats the correct elements but is often listed as a distractor; Option B is the standard recognized combination in clinical ophthalmology for trachomatous sequelae. * **Option D:** This is incomplete as it omits the lid margin malpositions (ectropion/entropion) that characterize the disease's morbidity. **NEET-PG High-Yield Pearls:** * **WHO SAFE Strategy:** **S**urgery (for trichiasis), **A**ntibiotics (Azithromycin 20mg/kg single dose), **F**acial cleanliness, **E**nvironmental improvement. * **Herbert’s Pits:** Pathognomonic scarred limbal follicles. * **Arlt’s Line:** Horizontal scar in the upper palpebral conjunctiva. * **Pannus:** Progressive (active) vs. Regressive (inactive) vascularization of the upper cornea.

Question 73: Epithelial xerosis of the conjunctiva is caused by?

A. Trachoma
B. Diphtheria
C. Xerophthalmia (Correct Answer)
D. Pemphigus

Explanation: **Explanation:** **Why Xerophthalmia is Correct:** Epithelial xerosis is the hallmark of **Vitamin A deficiency (Xerophthalmia)**. In this condition, the lack of Vitamin A leads to **squamous metaplasia** of the conjunctival epithelium. The normal non-keratinized stratified squamous epithelium transforms into a keratinized type. This process involves the loss of **goblet cells** (which produce the mucous layer of the tear film), leading to a dry, lusterless, and non-wettable appearance of the conjunctiva. This is clinically identified as **Bitot’s spots** (WHO Grade X1B). **Why Other Options are Incorrect:** * **Trachoma & Diphtheria:** These conditions cause **Parenchymatous xerosis**. This occurs due to extensive scarring (cicatrization) of the conjunctiva, which destroys the ducts of the lacrimal glands and goblet cells. It is a secondary structural complication rather than a primary epithelial metaplasia. * **Pemphigus:** This is an autoimmune blistering disease that leads to **Cicatricial Pemphigoid** in the eye. Like Trachoma, it causes xerosis via chronic inflammation and subepithelial fibrosis (Parenchymatous), not primary nutritional epithelial xerosis. **NEET-PG High-Yield Pearls:** * **Classification:** Xerosis is divided into **Epithelial** (Vitamin A deficiency) and **Parenchymatous** (Trachoma, Stevens-Johnson Syndrome, Chemical burns). * **WHO Grading of Xerophthalmia:** * **X1A:** Conjunctival xerosis (earliest clinical sign). * **X1B:** Bitot’s spots (foamy triangular patches). * **X2:** Corneal xerosis. * **X3A/B:** Corneal ulceration/Keratomalacia. * **XS:** Corneal scar. * **XN:** Night blindness (earliest symptom). * **Treatment:** The standard WHO schedule for Vitamin A is 200,000 IU orally on Days 0, 1, and 14 (half dose for infants 6–12 months).

Question 74: Arlt's line is seen on:

A. Cornea
B. Superior palpebral conjunctiva (Correct Answer)
C. Lacrimal gland
D. Bulbar conjunctiva

Explanation: **Explanation:** **Arlt’s line** is a classic clinical sign of **Trachoma**, a chronic keratoconjunctivitis caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C). It represents horizontal scarring of the conjunctiva. 1. **Why the correct answer is right:** In the cicatricial (scarring) stage of Trachoma (WHO Stage: TS), chronic inflammation leads to the formation of a horizontal band of scar tissue. This line is specifically located on the **superior palpebral conjunctiva**, running parallel to the eyelid margin at the junction of the anterior one-third and posterior two-thirds of the tarsal plate (the sulcus subtarsalis). It occurs due to the constant friction and inflammatory focus in this specific anatomical zone. 2. **Why the incorrect options are wrong:** * **Cornea:** While Trachoma affects the cornea (causing pannus and Herbert’s pits), Arlt’s line is strictly a conjunctival scarring phenomenon. * **Lacrimal gland:** Trachoma can cause dry eye due to scarring of the ductules of the lacrimal gland, but the "line" itself is not found here. * **Bulbar conjunctiva:** Although the bulbar conjunctiva may show congestion or scarring, the characteristic linear horizontal scar (Arlt's line) is localized to the palpebral (tarsal) surface. **Clinical Pearls for NEET-PG:** * **Herbert’s Pits:** Circular depressions on the limbus (remnants of healed limbal follicles); pathognomonic for Trachoma. * **Pannus:** Neovascularization and infiltration of the upper cornea (progressive vs. regressive). * **SAFE Strategy:** WHO-recommended management (Surgery, Antibiotics—Azithromycin, Facial cleanliness, Environmental improvement). * **Entropion/Trichiasis:** Common sequelae of the scarring represented by Arlt's line.

Question 75: Normal values of tear film break-up time range from:

A. 5 to 10 seconds
B. 10 to 15 seconds
C. 15 to 20 seconds
D. 15 to 30 seconds (Correct Answer)

Explanation: **Explanation:** The **Tear Film Break-up Time (BUT)** is a clinical test used to assess the **stability of the precorneal tear film**. It specifically measures the interval between a complete blink and the appearance of the first dry spot on the cornea. * **Why Option D is Correct:** In a healthy individual with a stable tear film, the normal BUT ranges from **15 to 30 seconds**. A value within this range indicates that the mucin layer (produced by conjunctival goblet cells) is adequately maintaining the interface between the aqueous layer and the corneal epithelium, preventing premature evaporation. * **Why Options A, B, and C are Incorrect:** These values represent varying degrees of tear film instability. Specifically, a BUT **less than 10 seconds** is considered diagnostic of an unstable tear film, often seen in **Evaporative Dry Eye** (due to Meibomian gland dysfunction) or **Mucin deficiency** (due to Vitamin A deficiency or Stevens-Johnson Syndrome). **High-Yield Clinical Pearls for NEET-PG:** 1. **Procedure:** It is performed by instilling **fluorescein dye** into the lower fornix and observing the tear film under a slit lamp using a **cobalt blue filter**. The patient is instructed not to blink. 2. **Significance:** BUT is the most sensitive test for **mucin deficiency** and tear film instability. 3. **Schirmer’s Test vs. BUT:** While BUT measures tear *quality/stability*, Schirmer’s test measures tear *quantity* (aqueous production). Normal Schirmer-I value is >15 mm in 5 minutes; <5 mm is diagnostic of aqueous deficiency (e.g., Sjögren’s syndrome). 4. **Rose Bengal Dye:** Used to stain dead and devitalized epithelial cells, making it useful for diagnosing Keratoconjunctivitis Sicca.

Question 76: Keratoconjunctivitis sicca refers to which type of dry eye?

A. Aqueous tear deficiency dry eye (Correct Answer)
B. Mucin deficiency dry eye
C. Lipid deficiency dry eye
D. All types of dry eye

Explanation: **Explanation:** **Keratoconjunctivitis Sicca (KCS)** specifically refers to dry eye caused by **Aqueous Tear Deficiency (ATD)**. The tear film consists of three layers: an outer lipid layer, a middle aqueous layer, and an inner mucin layer. KCS occurs when the lacrimal glands fail to produce enough of the middle aqueous component, leading to desiccation of the ocular surface. * **Why Option A is correct:** KCS is the clinical term for dry eye resulting from decreased aqueous production. It is further classified into **Sjögren’s KCS** (associated with autoimmune destruction of lacrimal glands) and **Non-Sjögren’s KCS** (associated with age, lacrimal gland duct obstruction, or systemic drugs). * **Why Option B is incorrect:** Mucin deficiency is typically caused by the destruction of **Goblet cells**, often seen in Vitamin A deficiency, Stevens-Johnson Syndrome, or chemical burns. * **Why Option C is incorrect:** Lipid deficiency is usually due to **Meibomian Gland Dysfunction (MGD)**. This leads to "Evaporative Dry Eye," where the quantity of tears is normal, but they evaporate too quickly. * **Why Option D is incorrect:** While "Dry Eye Disease" (DED) or "Xerophthalmia" are umbrella terms, KCS is a specific subset focused on aqueous volume. **High-Yield Clinical Pearls for NEET-PG:** 1. **Schirmer’s Test I:** Used to diagnose KCS. A value of **<5 mm in 5 minutes** is diagnostic of aqueous deficiency. 2. **Tear Film Break-up Time (TBUT):** An indicator of tear film stability (mucin/lipid layers). Normal is 15–35 seconds; **<10 seconds** is abnormal. 3. **Rose Bengal Stain:** Stains dead and devitalized epithelial cells, showing a characteristic "interpalpebral" pattern in KCS. 4. **Sjögren’s Syndrome Triad:** Dry eyes (KCS), dry mouth (Xerostomia), and a connective tissue disease (usually Rheumatoid Arthritis).

Question 77: Which of the following is NOT a feature of Vernal keratoconjunctivitis?

A. More common in summers
B. Cobblestone appearance
C. Fascicular corneal ulcer (Correct Answer)
D. Keratoconus

Explanation: **Explanation:** **Vernal Keratoconjunctivitis (VKC)**, also known as "Spring Catarrh," is a bilateral, recurrent, seasonal allergic inflammation of the conjunctiva, typically affecting young boys in warm climates. **Why Option C is the correct answer:** A **Fascicular corneal ulcer** is a characteristic feature of **Phlyctenular keratoconjunctivitis**, not VKC. It is a wandering ulcer that moves from the limbus toward the center of the cornea, carrying a leash of blood vessels behind it. In contrast, the classic corneal involvement in VKC includes punctate epithelial keratitis, **Shield ulcers** (large, oval, indolent apical ulcers), and Trantas spots. **Analysis of Incorrect Options:** * **Option A (More common in summers):** Despite the name "Spring Catarrh," VKC peak incidence occurs during hot, dry summer months due to increased allergen exposure and heat. * **Option B (Cobblestone appearance):** This is the hallmark of the **Palpebral form** of VKC. It results from the hypertrophy of papillae on the upper tarsal conjunctiva, which are flattened at the top by pressure from the globe, resembling "cobblestones" or "pavement stones." * **Option D (Keratoconus):** There is a strong association between VKC and Keratoconus. This is primarily due to chronic, vigorous eye rubbing (the "oculodigital reflex") triggered by the intense itching characteristic of the disease. **NEET-PG High-Yield Pearls:** * **Type of Hypersensitivity:** VKC involves both Type I (IgE-mediated) and Type IV (cell-mediated) reactions. * **Horner-Trantas Spots:** White, chalky dots at the limbus composed of eosinophils and epithelial debris (seen in the Limbal form). * **Maxwell-Lyons Sign:** A "ropey" or "stringy" discharge characteristic of VKC. * **Treatment:** Mast cell stabilizers (Prophylaxis), Topical Steroids (Acute flares), and Cyclosporine (Steroid-sparing).

Question 78: Follicles of 0.5 mm size are typically seen in which of the following conditions?

A. Pharyngoconjunctival fever
B. Trachoma (Correct Answer)
C. Drug-induced follicular conjunctivitis
D. Ophthalmia neonatorum

Explanation: **Explanation:** **Follicles** are subepithelial lymphoid aggregations that appear as pale, translucent, "rice-grain" like elevations. In **Trachoma** (caused by *Chlamydia trachomatis* serotypes A, B, Ba, and C), follicles are a hallmark feature. Specifically, mature follicles in Trachoma typically measure between **0.5 mm and 5.0 mm** in diameter. They are most prominent on the upper tarsal conjunctiva and, upon necrosis, lead to the pathognomonic **Herbert’s pits** at the limbus. **Analysis of Options:** * **Pharyngoconjunctival Fever (PCF):** Caused by Adenovirus (types 3, 7). While it presents with follicles, they are usually smaller and associated with high fever and pharyngitis. * **Drug-induced Follicular Conjunctivitis:** Often caused by long-term use of topical medications like Brimonidine, Pilocarpine, or Idoxuridine. These follicles are typically more prominent in the **lower fornix** rather than the upper tarsal plate. * **Ophthalmia Neonatorum:** This is neonatal conjunctivitis occurring within the first month of life. A key high-yield fact is that **follicles are NOT seen** in infants under 3–6 months of age because the conjunctival adenoid layer (lymphoid tissue) is not yet developed at birth. **High-Yield Clinical Pearls for NEET-PG:** * **Follicles vs. Papillae:** Follicles are lymphoid aggregates (vessels run *around* the swelling), whereas papillae are vascular structures (vessel is in the *center*). * **WHO Grading of Trachoma (FISTO):** * **TF (Trachomatous Inflammation—Follicular):** Presence of 5 or more follicles (>0.5 mm) on the upper tarsal conjunctiva. * **TI (Trachomatous Inflammation—Intense):** Pronounced inflammatory thickening obscuring >50% of deep tarsal vessels. * **Safe Strategy:** The WHO-recommended management for Trachoma (Surgery, Antibiotics, Facial cleanliness, Environmental improvement).

Question 79: Phlycten is due to:

A. Exogenous allergy
B. Endogenous allergy (Correct Answer)
C. Viral keratitis
D. Fungal keratitis

Explanation: **Explanation:** **Phlyctenular Keratoconjunctivitis** is a localized inflammatory response of the conjunctiva or cornea. The correct answer is **Endogenous allergy** because the condition represents a **Type IV hypersensitivity reaction** (delayed-type) to an endogenous microbial antigen to which the patient has been previously sensitized. * **Why Endogenous Allergy is correct:** The "phlycten" is a nodule formed by a collection of lymphocytes and macrophages. It is not an infection itself but an allergic response to proteins from bacteria already present in the body. Historically, the most common trigger was **Mycobacterium tuberculosis** (Tuberculoprotein). Today, the most common cause is **Staphylococcus aureus** (cell wall proteins from chronic blepharitis). * **Why other options are incorrect:** * **Exogenous allergy:** This refers to reactions to external allergens like pollen or dust (e.g., Vernal Keratoconjunctivitis), whereas phlycten is a reaction to internal microbial proteins. * **Viral/Fungal keratitis:** These are direct infectious processes caused by the invasion of pathogens into the corneal tissue, leading to suppuration or ulceration, rather than an immunologic hypersensitivity reaction. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** A small, pinkish-white nodule near the limbus with localized hyperaemia. * **Symptoms:** Intense lacrimation, photophobia, and blepharospasm (especially when the cornea is involved). * **Key Associations:** 1. *Staphylococcus aureus* (Most common worldwide). 2. *Mycobacterium tuberculosis* (Important in developing countries). 3. *Moraxella axenfeld* and certain fungi (rare). * **Treatment:** Topical steroids (to control the allergy) and treatment of the underlying cause (e.g., lid hygiene for blepharitis or systemic anti-TB drugs).

Question 80: A 10-year-old malnourished boy presents with a nodular elevation on the limbus which is congested and stains positive with fluorescein. What is the tentative diagnosis?

A. Pterygium
B. Pinguecula
C. Phlycten (Correct Answer)
D. Nodular episcleritis

Explanation: ### **Explanation** The clinical presentation of a **nodular elevation at the limbus** in a **malnourished child** is classic for **Phlyctenular Keratoconjunctivitis (Phlycten)**. **1. Why Phlycten is Correct:** A phlycten is a localized **Type IV hypersensitivity reaction** (delayed hypersensitivity) to endogenous bacterial proteins. * **Etiology:** Historically associated with **Tuberculosis** (especially in malnourished children in developing countries), but globally, the most common cause is **Staphylococcal proteins** (associated with blepharitis). * **Clinical Features:** It starts as a greyish-pink nodule at the limbus. The hallmark is that the nodule undergoes **necrosis and ulceration** at the apex, which explains why it **stains positive with fluorescein**. **2. Why Other Options are Incorrect:** * **Pterygium:** This is a triangular fibrovascular proliferation of the conjunctiva that encroaches onto the cornea. It is a degenerative condition (UV exposure) and does not present as an acute, staining nodule. * **Pinguecula:** A yellowish, stationary deposit of hyaline/elastotic tissue. It is asymptomatic, non-vascularized, and does not ulcerate or stain with fluorescein. * **Nodular Episcleritis:** While it presents as a localized nodule, it typically affects young adults (not specifically malnourished children). Crucially, the overlying conjunctiva is intact, so it **does not stain with fluorescein**. It also blanches with 10% phenylephrine, unlike deeper scleritis. **3. NEET-PG High-Yield Pearls:** * **Triad of Phlycten:** Photophobia, Lacrimation, and Blepharospasm (more severe if the cornea is involved). * **Fascicular Ulcer:** A migratory phlycten that carries a leash of blood vessels across the cornea, leaving a superficial scar. * **Treatment:** Topical steroids (to control inflammation) and investigation for the underlying cause (Chest X-ray/Mantoux test for TB; lid hygiene for Staph).

Practice by Chapter

Conjunctivitis: Bacterial

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Conjunctivitis: Viral

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Conjunctivitis: Allergic

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Conjunctivitis: Chronic

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Degenerations of Conjunctiva

Practice Questions

Benign Tumors of Conjunctiva

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Malignant Tumors of Conjunctiva

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Conjunctival Manifestations of Systemic Diseases

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Cicatricial Conjunctival Disorders

Practice Questions

Pterygium and Pinguecula

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Conjunctival Trauma

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Subconjunctival Hemorrhage

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