Diseases of the Conjunctiva Practice Questions

Q: What is the most common cause of neonatal conjunctivitis leading to blindness?

Gonococcus. **Explanation:** **Ophthalmia Neonatorum** (neonatal conjunctivitis) is defined as conjunctival inflammation occurring within the first 30 days of life. **Why Gonococcus is the correct answer:** While *Chlamydia trachomatis* is the most common cause of neonatal conjunctivitis overall in developed countries, **Neisseria gonorrhoeae** is the most **virulent** and the most common cause of **blindness**. Gonococcus is unique because it can penetrate an intact corneal epithelium, leading to rapid corneal ulceration, perforation, and subsequent endophthalmitis if not treated urgently. It typically presents 2–5 days after birth with profuse, thick purulent discharge and marked chemosis. **Analysis of Incorrect Options:** * **A. Chlamydia:** This is the most common infectious cause overall (presenting 5–14 days after birth). While it can cause scarring, it rarely leads to rapid blindness compared to the destructive nature of Gonococcus. * **B. Chemical irritation:** Usually caused by silver nitrate (Crede’s prophylaxis). It appears within the first 24 hours and is self-limiting, never leading to blindness. * **C. Herpes simplex virus:** A rare cause (presenting 1–2 weeks after birth) characterized by vesicular skin lesions and dendritic ulcers. While serious, it is statistically less common than Gonococcus as a cause of neonatal blindness. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Periods (Chronology):** Chemical (1 day) 7 days). * **Prophylaxis:** 1% Silver nitrate (historical) or 0.5% Erythromycin ointment (current standard). * **Treatment for Gonococcal:** Systemic Ceftriaxone (25–50 mg/kg IV/IM) is mandatory due to the risk of systemic dissemination. * **Key Sign:** Always look for "profuse purulent discharge" in the question stem to identify Gonococcus.

Q: Herbert's pits are classically seen in which part of the eye in trachoma?

Limbus. **Explanation:** **Herbert’s pits** are a pathognomonic clinical feature of **Trachoma** (caused by *Chlamydia trachomatis* serotypes A, B, Ba, and C). 1. **Why Limbus is correct:** During the active stage of follicular trachoma (Stage TF/TI), lymphoid follicles develop at the **limbus** (the junction of the cornea and sclera). These are known as **Herbert’s follicles**. As these follicles heal by cicatrization, they leave behind small, circular, shallow depressions filled with clear epithelial cells. These residual depressions are called **Herbert's pits**. They are most commonly found at the upper limbus and are a permanent diagnostic sign of past trachoma. 2. **Why other options are incorrect:** * **Lid margin:** While trachoma causes scarring leading to entropion and trichiasis at the lid margin, Herbert’s pits are specifically limbal. * **Palpebral conjunctiva:** This is the site for **Arlt’s line** (horizontal scarring) and follicles, but the specific "pitted" depressions following follicular necrosis are characteristic of the limbus. * **Bulbar conjunctiva:** This area may show congestion or chemosis, but it is not the primary site for the follicular necrosis that results in Herbert’s pits. **Clinical Pearls for NEET-PG:** * **Arlt’s Line:** Horizontal scarring in the upper palpebral conjunctiva (junction of anterior 1/3rd and posterior 2/3rd). * **Safe Strategy:** WHO’s approach to Trachoma control (**S**urgery, **A**ntibiotics—Azithromycin, **F**acial cleanliness, **E**nvironmental improvement). * **Pannus:** Trachomatous pannus is typically **progressive and superior** (vascularization and infiltration of the upper cornea). * **Classification:** Remember the **WHO (FISTO)** classification: **F**ollicular, **I**ntense, **S**carring, **T**richiasis, **O**pacity.

Q: Conjunctival xerosis is seen in -

Vitamin A deficiency. **Explanation:** **Conjunctival xerosis** is a hallmark clinical feature of **Vitamin A deficiency (VAD)**. The underlying pathophysiology involves the loss of mucus-secreting **goblet cells** and the transformation of the normal non-keratinized stratified squamous epithelium into a keratinized state (squamous metaplasia). This leads to a dry, lusterless, and "muddy" appearance of the conjunctiva, typically starting in the interpalpebral area. * **Vitamin A Deficiency (Correct):** It is the leading cause of xerophthalmia. According to the WHO classification, conjunctival xerosis is graded as **X1A**. It often precedes the development of Bitot’s spots (X1B), which are foamy triangular deposits on the bulbar conjunctiva. * **Herpetic Keratitis (Incorrect):** This is a viral infection caused by HSV, characterized by dendritic ulcers and decreased corneal sensations, rather than generalized conjunctival drying. * **Glaucoma (Incorrect):** This refers to a group of diseases characterized by optic neuropathy and increased intraocular pressure. While some chronic glaucoma medications (containing preservatives like BAK) can cause dry eye, the disease itself does not cause conjunctival xerosis. **High-Yield Clinical Pearls for NEET-PG:** * **WHO Classification of Xerophthalmia:** * X1A: Conjunctival xerosis * X1B: Bitot’s spots * X2: Corneal xerosis * X3A/X3B: Corneal ulceration/Keratomalacia * **Earliest Symptom:** Night blindness (Nyctalopia - XN). * **Earliest Sign:** Conjunctival xerosis (X1A). * **Treatment:** Oral Vitamin A (200,000 IU on days 0, 1, and 14 for children >1 year).

Q: Break-up Time (BUT) test is done in which of the following conditions?

Sjogren's syndrome. **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. **1. Why Sjogren’s Syndrome is Correct:** Sjogren’s syndrome is an autoimmune disorder characterized by lymphocytic infiltration of exocrine glands, leading to **Keratoconjunctivitis Sicca (Dry Eye)**. In this condition, the deficiency of the aqueous layer (and often the mucin layer) leads to an unstable tear film that evaporates rapidly. A **BUT of less than 10 seconds** is considered abnormal and diagnostic of tear film instability, a hallmark of Sjogren’s syndrome. **2. Why the Other Options are Incorrect:** * **Multiple Sclerosis:** A demyelinating CNS disease. While it can cause Optic Neuritis, it does not directly affect tear film stability. * **SLE (Systemic Lupus Erythematosus):** While SLE can occasionally cause secondary Sjogren’s, the BUT test is specifically a diagnostic tool for the *manifestation* of dry eyes (Sjogren's), not the systemic pathology of SLE itself. * **Myasthenia Gravis:** A neuromuscular junction disorder presenting with ptosis and diplopia; it does not involve the tear film layers. **High-Yield Clinical Pearls for NEET-PG:** * **Procedure:** BUT is performed by instilling **Fluorescein dye** and observing the eye under a cobalt blue filter on a slit lamp. * **Normal Value:** 15 to 35 seconds. **Abnormal:** 15mm in 5 mins; Abnormal: <5mm). * **Rose Bengal/Lissamine Green Stains:** Used to identify devitalized conjunctival and corneal epithelial cells in Sjogren's.

Q: Which of the following is seen in vernal catarrh?

Papillary hypertrophy. **Explanation:** **Vernal Keratoconjunctivitis (VKC)**, or "Spring Catarrh," is a bilateral, recurrent, external ocular inflammation primarily affecting young boys in warm climates. It is a **Type I and Type IV hypersensitivity reaction** to exogenous allergens. 1. **Why Papillary Hypertrophy is Correct:** The hallmark of VKC is the formation of **papillae**. These are vascularized tufts of inflammatory cells (primarily eosinophils, mast cells, and plasma cells). In the palpebral form, these papillae enlarge and flatten to form the characteristic **"Cobblestone" or "Pavement stone" appearance**. Papillae have a central vascular core, which distinguishes them from follicles. 2. **Why Other Options are Incorrect:** * **Follicles:** These are lymphoid aggregations (without a central vessel) typically seen in **Viral conjunctivitis** (e.g., Adenovirus), **Chlamydial infections** (Trachoma), or drug-induced reactions. * **Pannus formation:** This refers to superficial vascularization and scarring of the cornea. While VKC can involve the cornea (Shield ulcers, Trantas dots), a classic pannus is the hallmark of **Trachoma** (superior pannus) or Phlyctenular keratoconjunctivitis. **High-Yield Clinical Pearls for NEET-PG:** * **Trantas Dots:** White, chalky dots at the limbus consisting of eosinophils and epithelial debris (Pathognomonic for Limbal VKC). * **Shield Ulcer:** A sterile, transverse oval ulcer in the upper cornea due to mechanical rubbing by giant papillae. * **Maxwell-Lyons Sign:** A ropey, stringy discharge characteristic of VKC. * **Treatment:** Mast cell stabilizers (Cromolyn) for prophylaxis; Topical steroids for acute exacerbations.

Q: Phlyctenular keratoconjunctivitis is due to hypersensitivity to which of the following allergens?

Mycobacterium tuberculosis proteins. **Explanation:** **Phlyctenular Keratoconjunctivitis** is a localized **Type IV (Delayed) Hypersensitivity reaction** of the conjunctiva and cornea to endogenous microbial proteins to which the patient has been previously sensitized. **Why Option C is Correct:** Historically and most commonly in developing countries like India, the most frequent allergen is **Tuberculoprotein** (derived from *Mycobacterium tuberculosis*). Other common triggers include *Staphylococcus aureus* (cell wall proteins), and rarely, *Moraxella axenfeld* or fungal antigens like *Candida albicans*. The "phlycten" represents a lymphocytic infiltration in the subepithelial layer. **Why Other Options are Incorrect:** * **Options A & D (Pollen and Animal fur):** These are common triggers for **Type I (Immediate) Hypersensitivity** reactions, such as Seasonal Allergic Conjunctivitis (SAC) or Vernal Keratoconjunctivitis (VKC), characterized by IgE-mediated mast cell degranulation and itching. * **Option B (Chemicals):** These typically cause **Toxic Conjunctivitis** or direct chemical burns, which are irritant-mediated rather than a specific delayed hypersensitivity response to microbial proteins. **High-Yield Clinical Pearls for NEET-PG:** * **The Phlycten:** A characteristic pinkish-white nodule surrounded by a localized zone of hyperemia. It typically moves from the limbus toward the center of the cornea. * **Fascicular Ulcer:** A wandering corneal ulcer that carries a leash of blood vessels behind it; it is a classic complication of phlyctenular keratitis. * **Symptoms:** Intense photophobia (especially when the cornea is involved), lacrimation, and blepharospasm. * **Management:** Topical steroids for the ocular lesion, but it is **mandatory** to rule out systemic Tuberculosis (via Chest X-ray and Mantoux test) or treat associated staphylococcal blepharitis.

Q: Leber cells are most commonly seen in which of the following conditions?

Trachoma. **Explanation:** **Trachoma** (caused by *Chlamydia trachomatis* serotypes A, B, Ba, and C) is a chronic keratoconjunctivitis characterized by a mixed follicular and papillary response. **Leber cells** are large, multinucleated macrophages containing phagocytosed debris (necrotic material). They are found within the follicles of Trachoma. Their presence indicates follicular necrosis, which is a hallmark of the disease and eventually leads to the characteristic scarring (Arlt’s line). **Analysis of Incorrect Options:** * **A. Vernal Keratoconjunctivitis (VKC):** This is a Type I IgE-mediated hypersensitivity reaction. The predominant cells are **eosinophils** and mast cells. Characteristic findings include "cobblestone" papillae and Horner-Trantas dots. * **B. Phlyctenular Conjunctivitis:** This is a Type IV delayed hypersensitivity reaction to endogenous antigens (most commonly Tubercular protein). It is characterized by a "phlycten" (a small nodule) consisting of a perivascular cuff of **lymphocytes**. * **C. Ophthalmia Neonatorum:** This is acute conjunctivitis in a newborn. Depending on the etiology (e.g., *N. gonorrhoeae*), it typically presents with a massive **purulent discharge** and polymorphonuclear leucocytes, not necrotic follicles. **High-Yield Clinical Pearls for NEET-PG:** * **H. P. Bodies (Halberstaedter-Prowazek):** Intracytoplasmic inclusion bodies seen in Trachoma (epithelial cells). * **Herbert’s Pits:** Scarred-down limbal follicles, pathognomonic for Trachoma. * **SAFE Strategy:** WHO-recommended management (Surgery, Antibiotics, Facial cleanliness, Environmental improvement). * **Drug of Choice:** Single dose of Oral Azithromycin (20 mg/kg).

Q: A 6-year-old unvaccinated child presents with acute membranous conjunctivitis. Which of the following is TRUE about acute membranous conjunctivitis?

Peeling the membrane can cause bleeding.. **Explanation:** **1. Why Option B is Correct:** Acute membranous conjunctivitis is characterized by the formation of a **true membrane** on the palpebral conjunctiva. This occurs when the inflammatory exudate is rich in fibrin, which coagulates not just on the surface, but also involves the **superficial layers of the conjunctival epithelium**. Because the membrane is structurally integrated with the underlying tissue, any attempt to peel it off results in the tearing of the epithelium and small capillaries, leading to a **raw, bleeding surface**. **2. Analysis of Incorrect Options:** * **Option A:** This describes a **pseudomembrane** (seen in conditions like Adenoviral EKC or Vernal Keratoconjunctivitis). Pseudomembranes consist of coagulated exudate deposited *on* the epithelium and can be peeled easily without bleeding. * **Option C:** *Corynebacterium diphtheriae* is the classic causative agent of **true membranous conjunctivitis**, not a false (pseudo) membrane. In an unvaccinated child, Diphtheria must be the primary clinical suspicion. * **Option D:** The membrane *can* be removed manually, but it is discouraged in the acute phase due to the risk of significant bleeding and subsequent scarring (symblepharon). **3. High-Yield Clinical Pearls for NEET-PG:** * **Common Causes:** *C. diphtheriae* (most common in unvaccinated), virulent *Streptococcus pyogenes*. * **Clinical Stages:** 1. Stage of Infiltration (brawny edema), 2. Stage of Suppuration (membrane sloughing), 3. Stage of Cicatrization (scarring). * **Complications:** Symblepharon (adhesion of lids to eyeball), Trichiasis, and **Corneal Ulceration** (due to toxic enzymes or secondary infection). * **Treatment:** Immediate topical and systemic Penicillin/Erythromycin; Anti-diphtheritic serum (ADS) is critical if Diphtheria is suspected.

Q: Tear lysozyme levels are decreased in which of the following conditions?

Keratoconjunctivitis sicca. **Explanation:** **1. Understanding the Concept:** Lysozyme is a major antibacterial enzyme secreted by the **main and accessory lacrimal glands**. It accounts for about 20-40% of total tear protein. In conditions where there is primary lacrimal gland dysfunction or atrophy, the concentration of lysozyme in the tear film drops significantly. **Keratoconjunctivitis Sicca (KCS)**, specifically the aqueous-deficient subtype (often seen in Sjögren’s syndrome), is characterized by the hypofunction of the lacrimal glands. Therefore, a **decrease in tear lysozyme levels** is a classic biochemical marker for KCS and is used as a diagnostic indicator of lacrimal secretory capacity. **2. Analysis of Options:** * **A. Keratoconjunctivitis sicca (Correct):** As explained, the primary pathology involves reduced aqueous production from the lacrimal glands, leading to a direct fall in lysozyme levels. * **B & C. Stevens-Johnson Syndrome (SJS) and Ocular Pemphigoid (Incorrect):** While these conditions cause severe "dry eye," the primary mechanism is **mucin deficiency** due to the destruction of conjunctival goblet cells and scarring of the lacrimal gland ducts (obstructive) rather than a primary failure of lysozyme production itself. While lysozyme may eventually decrease in late stages, KCS is the classic textbook association for this specific biochemical change. **3. NEET-PG High-Yield Pearls:** * **Schirmer’s Test:** Used to measure aqueous tear production. <5mm in 5 minutes is diagnostic for dry eye. * **Tear Film Break-up Time (BUT):** Measures mucin deficiency/tear stability. Normal is 15–35 seconds; <10 seconds is abnormal. * **Rose Bengal Stain:** Stains dead and devitalized epithelial cells (useful in KCS). * **Lactoferrin:** Another antibacterial protein that, like lysozyme, is decreased in aqueous-deficient dry eye.

Q: Topical sodium cromoglycate is used in the treatment of which condition?

Vernal catarrh. ### Explanation **Correct Answer: B. Vernal catarrh** **Why it is correct:** Vernal Keratoconjunctivitis (VKC), or Vernal catarrh, is a bilateral, recurrent, seasonal allergic inflammation of the conjunctiva. It is primarily a **Type I hypersensitivity reaction** mediated by IgE and mast cell degranulation. **Sodium cromoglycate** is a **mast cell stabilizer**; it works by preventing the release of inflammatory mediators (like histamine) from mast cells. It is used as a prophylactic agent to reduce the frequency and severity of acute attacks in VKC. **Why the other options are incorrect:** * **Phlyctenular conjunctivitis:** This is a **Type IV hypersensitivity reaction** (delayed) to endogenous bacterial proteins (most commonly Tubercular or Staphylococcal). Treatment focuses on topical steroids and treating the underlying cause, not mast cell stabilization. * **Subconjunctival haemorrhage:** This is usually a self-limiting condition caused by the rupture of a small conjunctival vessel. It requires no specific treatment other than reassurance, as the blood resorbs within 1–2 weeks. * **Trachoma:** This is a chronic infectious keratoconjunctivitis caused by *Chlamydia trachomatis*. The mainstay of treatment is the **SAFE strategy**, specifically antibiotics like Azithromycin or Tetracycline. **High-Yield Clinical Pearls for NEET-PG:** * **VKC Hallmarks:** Characterized by "cobblestone" papillae on the superior tarsal conjunctiva, **Horner-Tranta’s dots** (limbal white dots), and **Shield ulcers** (sterile indolent ulcers). * **Drug of Choice for Acute Attack:** Topical steroids are used for rapid relief of symptoms, while mast cell stabilizers (Cromoglycate) or dual-action agents (Olopatadine) are used for long-term maintenance. * **Cytology:** Conjunctival scrapings in VKC characteristically show an abundance of **eosinophils**.

Question 1

What is the most common cause of neonatal conjunctivitis leading to blindness?

Accepted Answer

Gonococcus

Answer

Chlamydia

Answer

Chemical irritation

Answer

Herpes simplex virus

Question 2

Herbert's pits are classically seen in which part of the eye in trachoma?

Accepted Answer

Limbus

Answer

Lid margin

Answer

Palpebral conjunctiva

Answer

Bulbar conjunctiva

Question 3

Conjunctival xerosis is seen in -

Accepted Answer

Vitamin A deficiency

Answer

Herpetic keratitis

Answer

Glaucoma

Answer

None of the above

Question 4

Break-up Time (BUT) test is done in which of the following conditions?

Accepted Answer

Sjogren's syndrome

Answer

Multiple sclerosis

Answer

SLE

Answer

Myasthenia gravis

Question 5

Which of the following is seen in vernal catarrh?

Accepted Answer

Papillary hypertrophy

Answer

Follicles

Answer

Pannus formation

Answer

All of the above

Question 6

Phlyctenular keratoconjunctivitis is due to hypersensitivity to which of the following allergens?

Accepted Answer

Mycobacterium tuberculosis proteins

Answer

Pollen

Answer

Chemicals

Answer

Animal fur

Question 7

Leber cells are most commonly seen in which of the following conditions?

Accepted Answer

Trachoma

Answer

Vernal keratoconjunctivitis

Answer

Phlyctenular conjunctivitis

Answer

Ophthalmia neonatorum

Question 8

A 6-year-old unvaccinated child presents with acute membranous conjunctivitis. Which of the following is TRUE about acute membranous conjunctivitis?

Accepted Answer

Peeling the membrane can cause bleeding.

Answer

The membrane is easy to peel.

Answer

Diphtheria causes a false membrane.

Answer

The membrane cannot be removed.

Question 9

Tear lysozyme levels are decreased in which of the following conditions?

Accepted Answer

Keratoconjunctivitis sicca

Answer

Stevens Johnson syndrome

Answer

Ocular pemphigoid

Answer

All of the above

Question 10

Topical sodium cromoglycate is used in the treatment of which condition?

Accepted Answer

Vernal catarrh

Answer

Phlyctenular conjunctivitis

Answer

Subconjunctival haemorrhage

Answer

Trachoma

Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva — MCQs

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