Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva Indian Medical PG Practice Questions and MCQs

Question 41: Egyptian ophthalmia is?

A. Spring catarrh
B. Trachoma (Correct Answer)
C. Interstitial keratitis
D. Xerophthalmia

Explanation: **Explanation:** **Trachoma** is historically known as **Egyptian ophthalmia** because it was highly endemic in Egypt and the Middle East, particularly noted during the Napoleonic campaigns. It is a chronic keratoconjunctivitis caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C). It remains a leading cause of preventable blindness worldwide. **Why the other options are incorrect:** * **Spring catarrh (Vernal Keratoconjunctivitis):** This is a bilateral, recurrent, seasonal allergic inflammation of the conjunctiva, typically characterized by "cobblestone" papillae. It is not associated with the term Egyptian ophthalmia. * **Interstitial keratitis:** This refers to inflammation of the corneal stroma without primary involvement of the epithelium or endothelium. It is most commonly associated with Congenital Syphilis (Hutchinson’s triad) or TB, rather than Chlamydial infection. * **Xerophthalmia:** This is a spectrum of ocular manifestations resulting from Vitamin A deficiency, ranging from night blindness to keratomalacia. **High-Yield Clinical Pearls for NEET-PG:** 1. **WHO Grading (FISTO):** **F**ollicular, **I**ntense inflammation, **S**carring (Arlt’s line), **T**richiasis, and **O**pacity (Corneal). 2. **Pathognomonic Signs:** **Herbert’s pits** (scarred follicles at the limbus) and **Arlt’s line** (horizontal scarring in the palpebral conjunctiva). 3. **SAFE Strategy:** **S**urgery (for trichiasis), **A**ntibiotics (Azithromycin 20mg/kg single dose), **F**acial cleanliness, and **E**nvironmental improvement. 4. **Vector:** The common housefly (*Musca sorbens*) acts as a mechanical vector.

Question 42: What percentage of silver nitrate is used in Credé's method?

A. 1 percent (Correct Answer)
B. 0.5 percent
C. 1.5 percent
D. 2 percent

Explanation: **Explanation:** **Credé’s prophylaxis** is a historical yet high-yield clinical method used for the prevention of **Ophthalmia Neonatorum** (neonatal conjunctivitis), specifically targeting *Neisseria gonorrhoeae*. 1. **Why 1% is Correct:** The standard procedure involves the instillation of a single drop of **1% Silver Nitrate** solution into each conjunctival sac of the newborn immediately after birth. Silver nitrate acts as a potent antiseptic by precipitating bacterial proteins. While highly effective against Gonococcus, its use has largely been replaced by erythromycin or tetracycline ointments in many regions because silver nitrate frequently causes **chemical conjunctivitis** (typically appearing within 6–24 hours and resolving spontaneously). 2. **Analysis of Incorrect Options:** * **0.5% and 1.5%:** These concentrations are not standardized for this procedure. A 0.5% concentration would be sub-therapeutic for prophylaxis, while 1.5% increases the risk of severe chemical irritation without added benefit. * **2%:** This concentration is too caustic for the delicate neonatal ocular surface and can lead to significant corneal epithelial damage or permanent scarring. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Ophthalmia Neonatorum:** Currently, *Chlamydia trachomatis* (though Silver Nitrate is specifically for *N. gonorrhoeae*). * **Incubation Periods:** * *Chemical (Silver Nitrate):* 6–24 hours. * *Gonococcal:* 2–5 days (Most hyperacute/destructive). * *Chlamydial:* 5–14 days (Most common). * **Modern Alternative:** 1% Tetracycline or 0.5% Erythromycin ointment is now preferred over Credé’s method to avoid chemical irritation.

Question 43: Herbert's pits are classically seen in which part of the eye in trachoma?

A. Limbus (Correct Answer)
B. Lid margin
C. Palpebral conjunctiva
D. Bulbar conjunctiva

Explanation: **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.

Question 44: Pharyngoconjunctival fever is caused by which of the following viruses?

A. Parainfluenza virus
B. Haemophilus influenza
C. Coxsackie virus
D. Adenovirus (Correct Answer)

Explanation: **Explanation:** **Pharyngoconjunctival Fever (PCF)** is a specific clinical syndrome caused by **Adenovirus**, most commonly **serotypes 3, 4, and 7**. It typically presents as a triad of: 1. **Follicular conjunctivitis** (usually non-purulent) 2. **Pharyngitis** (sore throat) 3. **Fever** The infection is highly contagious, often spreading through respiratory droplets or contaminated water in swimming pools (hence the name "Swimming Pool Conjunctivitis"). It is usually self-limiting, lasting 7–14 days. **Analysis of Incorrect Options:** * **Parainfluenza virus:** Primarily causes respiratory infections like Croup (laryngotracheobronchitis) in children, not a specific conjunctivitis syndrome. * **Haemophilus influenzae:** This is a bacterium, not a virus. While it can cause bacterial conjunctivitis (especially in children), it does not cause the viral follicular pattern seen in PCF. * **Coxsackie virus:** Specifically Coxsackie A24 (and Enterovirus 70) are the primary causes of **Acute Hemorrhagic Conjunctivitis (AHC)**, characterized by subconjunctival hemorrhages, rather than the pharyngitis-fever triad. **High-Yield Clinical Pearls for NEET-PG:** * **Epidemic Keratoconjunctivitis (EKC):** Also caused by Adenovirus (Serotypes **8, 19, 37**). Unlike PCF, EKC is more severe, lacks systemic symptoms (no fever/sore throat), and is notorious for causing **subepithelial corneal infiltrates**. * **Transmission:** Adenovirus is resistant to many common disinfectants; handwashing and instrument sterilization (tonometers) are crucial to prevent outbreaks. * **Management:** Treatment is primarily supportive (cold compresses and artificial tears) as it is a self-limiting viral condition.

Question 45: Conjunctival xerosis is seen in -

A. Vitamin A deficiency (Correct Answer)
B. Herpetic keratitis
C. Glaucoma
D. None of the above

Explanation: **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).

Question 46: In the grading of trachoma, trachomatous inflammation - follicular is defined as the presence of which of the following?

A. 5 or more follicles in the lower tarsal conjunctiva
B. 3 or more follicles in the lower tarsal conjunctiva
C. 5 or more follicles in the upper tarsal conjunctiva (Correct Answer)
D. 3 or more follicles in the upper tarsal conjunctiva

Explanation: ### Explanation The correct answer is **C: 5 or more follicles in the upper tarsal conjunctiva.** This definition is based on the **WHO Simplified Grading System (FISTO)** for Trachoma, introduced in 1987 to facilitate field work by non-specialists. **1. Why Option C is Correct:** According to the WHO criteria, **Trachomatous inflammation—follicular (TF)** is defined as the presence of **five or more follicles** in the **central part of the upper tarsal conjunctiva**, each being at least **0.5 mm** in diameter. The upper tarsal conjunctiva is the primary site of clinical assessment because trachoma is a disease that predominantly affects the upper lid, leading to its characteristic complications like cicatricial entropion. **2. Why Other Options are Incorrect:** * **Options A & B (Lower Tarsal Conjunctiva):** Follicles in the lower conjunctiva are non-specific and can occur in various types of viral or toxic conjunctivitis. They are not diagnostic for trachoma grading. * **Option D (3 or more follicles):** This does not meet the WHO threshold. The requirement of at least five follicles ensures higher specificity for diagnosing active trachoma in endemic areas. **3. Clinical Pearls for NEET-PG:** * **WHO "FISTO" Grading:** * **T**F: Follicular (5+ follicles, >0.5mm). * **T**I: Intense (Inflammation obscuring >50% of deep tarsal vessels). * **T**S: Scarring (White fibrous bands). * **T**T: Trichiasis (At least one lash rubbing the eyeball). * **C**O: Corneal Opacity (Over the pupil). * **SAFE Strategy:** **S**urgery (for TT), **A**ntibiotics (Azithromycin), **F**acial cleanliness, **E**nvironmental improvement. * **Arlt’s Line:** Horizontal scar in the sulcus subtarsalis (seen in TS). * **Herbert’s Pits:** Scarred-down limbal follicles (pathognomonic).

Question 47: Break-up Time (BUT) test is done in which of the following conditions?

A. Sjogren's syndrome (Correct Answer)
B. Multiple sclerosis
C. SLE
D. Myasthenia gravis

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. **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:** < 10 seconds. * **Schirmer’s Test:** Another vital test for dry eyes; it measures the *quantity* of tear production (Normal: >15mm in 5 mins; Abnormal: <5mm). * **Rose Bengal/Lissamine Green Stains:** Used to identify devitalized conjunctival and corneal epithelial cells in Sjogren's.

Question 48: Rosettes found at the lid margin are a feature of which condition?

A. Ulcerative blepharitis (Correct Answer)
B. Squamous blepharitis
C. Both of the above
D. None of the above

Explanation: ### Explanation **Ulcerative Blepharitis** is a chronic staphylococcal infection of the lash follicles and associated glands (Zeis and Moll). The hallmark of this condition is the formation of small pustules at the base of the eyelashes. When these pustules rupture, they form yellowish crusts that glue the lashes together. **Why "Rosettes"?** When these crusts are removed, they leave behind small, bleeding **ulcers**. The arrangement of these crusts and the underlying inflammatory reaction around the lash follicles often give a characteristic **"rosette" appearance** at the lid margin. This is a classic diagnostic sign for the ulcerative (staphylococcal) variety. **Analysis of Other Options:** * **Squamous Blepharitis:** This is a metabolic/seborrheic condition, not primarily infectious. It is characterized by **dandruff-like scales** (scurf) on the lid margins. Unlike the ulcerative type, these scales are easily removed without leaving ulcers or bleeding points, and no rosettes are formed. * **Both/None:** Since the pathology of ulceration and crusting is specific to staphylococcal infection, it does not occur in the squamous variety. **High-Yield Clinical Pearls for NEET-PG:** * **Complications of Ulcerative Blepharitis:** Chronic infection can lead to **Madrone (loss of lashes)**, **Trichiasis (misdirected lashes)**, **Poliosis (whitening of lashes)**, and **Tylosis (thickening of lid margins)**. * **Etiology:** Most commonly caused by *Staphylococcus aureus*. * **Treatment:** Requires lid hygiene (warm compresses) and topical antibiotic ointments (e.g., Bacitracin or Erythromycin). * **Key Differentiator:** Bleeding ulcers upon crust removal = Ulcerative; No ulcers/dry scales = Squamous.

Question 49: Pseudomembranous conjunctivitis is caused by which organism?

A. Neisseria gonorrhoeae
B. Staphylococcus aureus
C. Streptococcus pyogenes (Correct Answer)
D. Keratoconjunctivitis sicca

Explanation: **Explanation:** **Pseudomembranous conjunctivitis** is characterized by the formation of a "false membrane" on the conjunctiva, consisting of coagulated exudate, fibrin, and inflammatory cells. Unlike a true membrane, a pseudomembrane can be easily peeled off without significant bleeding because it does not involve the underlying epithelium. 1. **Why Streptococcus pyogenes is correct:** * **Streptococcus pyogenes** (Group A Beta-hemolytic Streptococcus) is the most common cause of pseudomembranous conjunctivitis. It produces potent exotoxins and enzymes that lead to intense inflammation and the deposition of fibrin on the conjunctival surface. Other common causes include *Staphylococcus aureus* (less common than Strep), *Adenovirus* (Epidemic Keratoconjunctivitis), and *Corynebacterium diphtheriae* (mild cases). 2. **Analysis of Incorrect Options:** * **Neisseria gonorrhoeae:** Typically causes **Hyperacute Purulent Conjunctivitis**. It is characterized by profuse, thick, creamy pus and is a medical emergency due to its ability to penetrate an intact corneal epithelium. * **Staphylococcus aureus:** While it can occasionally cause pseudomembranes, it is primarily the leading cause of **Acute Mucopurulent Conjunctivitis** and blepharoconjunctivitis. * **Keratoconjunctivitis sicca:** This is a non-infectious condition (Dry Eye Syndrome) caused by tear film instability. It does not involve membrane formation. **High-Yield Clinical Pearls for NEET-PG:** * **True Membrane vs. Pseudomembrane:** True membranes (caused by **Corynebacterium diphtheriae**) leave a bleeding surface when peeled. Pseudomembranes (caused by **Strep. pyogenes**) do not bleed upon removal. * **Viral Cause:** Adenovirus (Serotypes 8, 11, 19) is the most common viral cause of pseudomembranous conjunctivitis. * **Ligneous Conjunctivitis:** A rare, chronic form of pseudomembranous conjunctivitis caused by **Plasminogen deficiency**.

Question 50: Which of the following is seen in vernal catarrh?

A. Papillary hypertrophy (Correct Answer)
B. Follicles
C. Pannus formation
D. All of the above

Explanation: **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.

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

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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

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Pterygium and Pinguecula

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Conjunctival Trauma

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Subconjunctival Hemorrhage

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