Diseases of the Conjunctiva Practice Questions

Q: Which of the following is NOT a cause of tear film deficiency?

Systemic Vitamin C deficiency. To understand tear film deficiency, one must recall the three layers of the tear film: **Mucin** (inner), **Aqueous** (middle), and **Lipid** (outer). A deficiency in any of these leads to Dry Eye Disease (Keratoconjunctivitis Sicca). ### Why "Systemic Vitamin C deficiency" is the correct answer: Vitamin C (Ascorbic acid) is essential for collagen synthesis and wound healing. While its deficiency causes Scurvy (leading to corkscrew hair and bleeding gums), it is **not** a primary cause of tear film deficiency. In contrast, **Vitamin A deficiency** is a major cause of tear film instability because it leads to the loss of conjunctival goblet cells, resulting in mucin deficiency and Xerophthalmia. ### Analysis of Incorrect Options: * **Infiltrative disease of lacrimal glands:** Conditions like Sarcoidosis, Lymphoma, or Amyloidosis destroy the lacrimal acini, leading to **Aqueous deficiency**. * **Post corneal transplant:** Corneal surgery (including Keratoplasty and LASIK) severs the long ciliary nerves. This causes **neurotrophic epitheliopathy**, decreasing the sensory feedback loop to the lacrimal gland, thereby reducing tear production. * **Congenital absence of meibomian glands:** Meibomian glands produce the lipid layer. Their absence or dysfunction (MGD) leads to **evaporative tear film deficiency**, as the aqueous layer evaporates rapidly without the protective lipid seal. ### High-Yield Clinical Pearls for NEET-PG: * **Schirmer’s Test I:** Measures total tear secretion (Normal: >15mm in 5 mins). <5mm is diagnostic of dry eye. * **Tear Film Break-up Time (TBUT):** Measures mucin/lipid stability. Normal is 15–35 seconds; <10 seconds indicates instability. * **Sjögren’s Syndrome:** A classic triad of dry eyes, dry mouth, and connective tissue disease (e.g., Rheumatoid Arthritis). * **Vitamin A:** Essential for maintaining the health of the non-keratinized squamous epithelium of the conjunctiva.

Q: What is the term for a white plaque in the eye caused by vitamin A deficiency?

Bitot spot. **Explanation:** **Bitot’s spots** are the hallmark clinical sign of Vitamin A deficiency (Xerophthalmia). They are characterized by triangular, foamy, silvery-white plaques typically located on the bulbar conjunctiva, most commonly in the temporal quadrant. The underlying medical concept involves **squamous metaplasia** of the conjunctival epithelium. Vitamin A is essential for maintaining goblet cells; its deficiency leads to a loss of these cells and keratinization of the conjunctiva. The "foamy" appearance is caused by the accumulation of keratin debris and the gas-producing bacilli, *Corynebacterium xerosis*. **Analysis of Incorrect Options:** * **Pink spot:** This is not a standard ophthalmological term. It may be confused with a "Cherry-red spot," which is seen in Central Retinal Artery Occlusion (CRAO) or Tay-Sachs disease. * **White spot:** While Bitot’s spots are white, this is a generic descriptive term and not the specific medical eponym required for the diagnosis. * **Herald spot:** This term is associated with dermatology (the "Herald patch" in Pityriasis rosea), not ophthalmology. **High-Yield Clinical Pearls for NEET-PG:** * **WHO Classification:** Bitot’s spots are classified as stage **X1B** of Xerophthalmia. * **Reversibility:** Bitot’s spots in children are usually reversible with high-dose Vitamin A therapy, but in adults, they may persist as permanent sequelae of past deficiency. * **Night Blindness (Nyctalopia):** This is the earliest clinical symptom (X1A) of Vitamin A deficiency, whereas Bitot’s spots are the most common objective sign. * **Treatment:** The WHO protocol for children >1 year is 200,000 IU of Vitamin A orally on days 0, 1, and 14.

Q: Which drug should be avoided in a case of spring catarrh?

Antibiotics. **Explanation:** **Spring Catarrh (Vernal Keratoconjunctivitis - VKC)** is a bilateral, recurrent, seasonal allergic inflammation of the conjunctiva, primarily driven by a Type I hypersensitivity reaction to allergens like pollen. **Why Antibiotics are avoided:** The underlying pathology of VKC is **allergic**, not bacterial. Antibiotics have no therapeutic role in treating an allergy. Furthermore, their unnecessary use is contraindicated because: 1. They can cause **medicamentosa** (drug-induced conjunctivitis), worsening the patient's discomfort. 2. They contribute to **antimicrobial resistance**. 3. They may cause hypersensitivity reactions in an already sensitized ocular surface. **Analysis of Incorrect Options:** * **Methylcellulose (Lubricants):** These are beneficial as they provide a barrier against allergens and wash away inflammatory mediators from the ocular surface. * **Steroids:** These are the "gold standard" for managing acute exacerbations of VKC due to their potent anti-inflammatory action. However, they must be used under supervision to avoid glaucoma and cataracts. * **Antihistamines:** These are a mainstay of treatment (often combined with mast cell stabilizers) to provide symptomatic relief from itching. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark symptoms:** Intense itching, ropy discharge, and photophobia. * **Key signs:** Cobblestone papillae (Palpebral form), Horner-Trantas dots (Limbal form), and Shield ulcers (Corneal involvement). * **Treatment Ladder:** Mast cell stabilizers (Cromolyn) for prophylaxis → Topical Antihistamines → Topical Steroids (for pulses) → Cyclosporine/Tacrolimus (for steroid-sparing).

Q: Which bacterium does NOT cause ophthalmia neonatorum?

Moraxella. **Explanation:** **Ophthalmia Neonatorum** is defined as bilateral inflammation of the conjunctiva occurring within the first 30 days of life. It is a medical emergency because certain pathogens can lead to corneal perforation and permanent blindness. **Why Moraxella is the correct answer:** While *Moraxella lacunata* is a well-known cause of **angular conjunctivitis** in adults and older children, it is not a recognized cause of ophthalmia neonatorum. The etiology of neonatal conjunctivitis is strictly categorized into chemical, bacterial (specifically those colonizing the maternal birth canal), and viral causes. **Analysis of incorrect options:** * **Chlamydia trachomatis (Serotypes D-K):** The most common infectious cause worldwide. It typically presents 5–14 days after birth. * **Neisseria gonorrhoeae:** The most serious cause. It presents early (2–5 days) with profuse purulent discharge and can penetrate an intact corneal epithelium, leading to perforation. * **Pseudomonas aeruginosa:** Though less common than Chlamydia, it is a recognized bacterial cause that can occur in hospital settings (NICU) or via contaminated equipment. It is highly destructive to the neonatal cornea. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Periods (The "Golden Rule"):** * *Chemical (Silver Nitrate):* 0–24 hours. * *Gonococcus:* 2–5 days (Most hyperacute). * *Chlamydia:* 5–14 days (Most common). * *Herpes Simplex (HSV-2):* 1–2 weeks. * **Prophylaxis:** 1% Silver nitrate (Credé’s method) or 0.5% Erythromycin ointment. * **Treatment:** Systemic treatment is mandatory for Chlamydia (Oral Erythromycin) and Gonococcus (Ceftriaxone) to prevent systemic complications like pneumonia or sepsis.

Q: Which of the following conjunctivitis can also involve the intact cornea?

Acute purulent conjunctivitis. **Explanation:** The correct answer is **Acute purulent conjunctivitis** (also known as Hyperacute conjunctivitis). **1. Why the correct answer is right:** The hallmark of acute purulent conjunctivitis, most commonly caused by *Neisseria gonorrhoeae* or *Neisseria meningitidis*, is its ability to invade an **intact corneal epithelium**. Most bacteria require a pre-existing epithelial defect to cause a corneal ulcer; however, certain organisms possess virulent enzymes (proteases) that allow them to penetrate healthy corneal tissue directly. This can lead to rapid corneal perforation and endophthalmitis if not treated urgently. **2. Why the incorrect options are wrong:** * **A. Acute mucopurulent conjunctivitis:** Typically caused by *Staphylococcus aureus* or *Streptococcus pneumoniae*. While it causes significant discharge and "red eye," it does not involve the cornea unless there is prior trauma or severe drying. * **B. Acute membranous conjunctivitis:** Classically caused by *Corynebacterium diphtheriae*. While it can cause corneal scarring due to the severity of the inflammation and membrane formation, it does not typically penetrate an intact cornea as aggressively as *Neisseria*. * **C. Angular conjunctivitis:** Caused by *Moraxella axenfelditis*. It is characterized by excoriation of the skin at the inner and outer canthi due to proteases, but it does not involve the central cornea. **3. Clinical Pearls for NEET-PG:** * **Mnemonic for organisms that can penetrate intact cornea:** "**CHLNS**" * **C**orynebacterium diphtheriae * **H**aemophilus aegyptius * **L**isteria monocytogenes * **N**eisseria gonorrhoeae / meningitidis * **S**higella * **Treatment:** Purulent conjunctivitis due to *N. gonorrhoeae* is a medical emergency requiring systemic Ceftriaxone. * **Clinical Sign:** Look for "copious, thick, creamy pus" dripping from the eyelids.

Q: Circumcorneal congestion is seen in all of the following conditions, EXCEPT:

Moraxella infection. **Explanation:** The key to answering this question lies in differentiating between **Circumcorneal (Ciliary) Congestion** and **Conjunctival Congestion**. **Why Moraxella infection is the correct answer:** Moraxella lacunata typically causes **Angular Conjunctivitis**. This condition is characterized by **conjunctival congestion** (superficial vessels) localized specifically to the inner and outer canthi (angles) of the eye. It does not involve the deep ciliary vessels. Therefore, it presents with superficial redness rather than circumcorneal congestion. **Analysis of Incorrect Options:** Circumcorneal congestion involves the deep ciliary vessels and is a hallmark of **keratitis, iridocyclitis, or acute glaucoma**. * **Anterior Uveitis (Iridocyclitis):** Inflammation of the uveal tract triggers deep ciliary vessel engorgement, presenting as a typical dusky-red circumcorneal flush. * **Acute Congestive Glaucoma:** The sudden, massive rise in intraocular pressure leads to venous stasis and intense ciliary congestion. * **Stevens-Johnson Syndrome (SJS):** In the acute phase, SJS causes severe ocular surface inflammation, including intense conjunctivitis and often secondary keratitis or corneal involvement, which leads to circumcorneal congestion. **NEET-PG High-Yield Pearls:** 1. **Ciliary Congestion:** Vessels are deep, purple/dusky red, do not move with the conjunctiva, and do not blanch with 1:1000 adrenaline. It indicates serious intraocular pathology. 2. **Conjunctival Congestion:** Vessels are superficial, bright red, move with the conjunctiva, and **blanch with adrenaline**. It indicates superficial pathology (conjunctivitis). 3. **Moraxella Lacunata:** Classically associated with "maceration of the skin at the angles" due to the production of a proteolytic enzyme (protease). Treatment is Zinc Oxide or Oxytetracycline.

Q: What type of corneal ulcer is typically seen in Vernal keratoconjunctivitis?

Shield ulcer. ### Explanation **Correct Answer: D. Shield ulcer** **Mechanism and Pathophysiology:** Vernal Keratoconjunctivitis (VKC) is a bilateral, recurrent, allergic inflammation of the conjunctiva, typically affecting young boys. A **Shield Ulcer** is a characteristic corneal complication seen in the palpebral or mixed forms of VKC. It is a **sterile, indolent, oval, or transversely oriented** epithelial defect located in the upper part of the cornea. The pathogenesis involves two factors: 1. **Mechanical:** Constant rubbing of the cornea by hard, "cobblestone" papillae on the superior palpebral conjunctiva. 2. **Chemical:** Inflammatory mediators and "Major Basic Protein" (MBP) released from eosinophils inhibit corneal epithelial healing, leading to a non-healing ulcer with a plaque-like base of mucus and fibrin. **Analysis of Incorrect Options:** * **A. Dendritic pattern:** Characterized by linear, branching ulcers with terminal bulbs; pathognomonic for **Herpes Simplex Keratitis** (epithelial). * **B. Pseudodendritic pattern:** Similar to dendritic but lacks terminal bulbs and is more elevated. Seen in **Herpes Zoster Ophthalmicus**, Acanthamoeba keratitis, or Tyrosinemia Type II. * **C. Geological (Geographic) ulcer:** A large, amoeboid-shaped ulcer formed when dendritic ulcers coalesce, often worsened by the inappropriate use of topical steroids in HSV keratitis. **High-Yield Clinical Pearls for NEET-PG:** * **VKC Triad:** Cobblestone papillae (palpebral), Horner-Trantas dots (limbal), and Shield ulcer (corneal). * **Maxwell-Lyons Sign:** A "ropy" discharge characteristic of VKC. * **Treatment of Shield Ulcer:** Includes topical steroids, mast cell stabilizers, and sometimes surgical debridement of the plaque to allow re-epithelialization. * **Classification:** Shield ulcers are graded (Stage 1-3) based on the presence of plaque and depth of the ulcer.

Q: In pterygium, which layer of the cornea is most commonly involved?

Bowman's layer. ### Explanation **Correct Answer: C. Bowman’s layer** **Mechanism and Pathophysiology:** A pterygium is a triangular, fibrovascular proliferation of the subconjunctival tissue that encroaches onto the cornea. The hallmark of its progression is the **destruction of Bowman’s layer**. The pathological process involves elastotic degeneration of the collagen fibers. As the pterygium advances, it invades and replaces the superficial stroma and Bowman's membrane, which is why surgical excision often leaves a permanent corneal scar at the site. **Analysis of Incorrect Options:** * **A. Epithelium:** While the epithelium covers the pterygium, it is not the primary site of structural involvement or destruction. The pathology originates beneath the epithelium. * **B. Endothelium:** This is the innermost layer of the cornea. Pterygium is a superficial ocular surface disorder and does not extend to the deep posterior layers. * **D. Descemet’s membrane:** Similar to the endothelium, this is a deep layer. Pterygium is limited to the anterior corneal layers (Epithelium, Bowman’s, and superficial Stroma). **Clinical Pearls for NEET-PG:** * **Stocker’s Line:** An iron deposit (hemosiderin) seen on the corneal epithelium at the leading edge (head) of a stable pterygium. * **Fuchs’ Flecks:** Small, greyish-white opacities seen at the advancing edge, representing precursors to progression. * **Etiology:** Strongly associated with chronic **UV-B exposure** and dry, dusty environments. * **Treatment of Choice:** Surgical excision with **Limbal Conjunctival Autograft (CAG)** is the gold standard to minimize recurrence. * **Recurrence:** The most common complication after simple "bare sclera" excision. Mitomycin-C is sometimes used as an adjuvant to prevent this.

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

Chlamydia. **Explanation:** **Ophthalmia Neonatorum** (neonatal conjunctivitis) is defined as any discharge or inflammation of the conjunctiva occurring within the first month of life. **Why Chlamydia is Correct:** * **Chlamydia trachomatis (Serotypes D-K)** is currently the **most common infectious cause** of neonatal conjunctivitis worldwide. * It typically presents **5 to 14 days** after birth. * The clinical presentation ranges from mild hyperemia to severe papillary conjunctivitis with pseudomembrane formation. Because neonates lack lymphoid tissue in the conjunctiva at birth, follicles are not seen (unlike in adults). **Analysis of Incorrect Options:** * **Chemical irritation:** Historically common due to Silver Nitrate (Credé’s prophylaxis), it appears within the **first 24 hours** and resolves spontaneously. It is the most common cause in the first day of life, but not overall. * **Gonococcus (Neisseria gonorrhoeae):** This is the **most hyperacute and vision-threatening** cause, appearing **2 to 5 days** after birth. It causes profuse purulent discharge and can penetrate an intact corneal epithelium. * **Herpes simplex (HSV-2):** A rare cause appearing **1 to 2 weeks** after birth, typically associated with vesicular skin lesions and dendritic keratitis. **High-Yield Clinical Pearls for NEET-PG:** 1. **Timeline is Key:** Chemical (24 hrs) → Gonococcal (2–5 days) → Chlamydia (5–14 days) → HSV (1–2 weeks). 2. **Treatment of Choice:** For Chlamydia, **Oral Erythromycin** (50 mg/kg/day for 14 days) is mandatory to treat the ocular infection and prevent Chlamydial pneumonia. 3. **Diagnosis:** Giemsa stain showing **Halberstaedter-Prowazek (HP) inclusion bodies** is characteristic of Chlamydia.

Q: A chronic alcoholic complains of congestion around the lateral canthus and burning sensation with discomfort of the eyes. What is the probable diagnosis?

Angular conjunctivitis. ### Explanation **Correct Answer: C. Angular conjunctivitis** **Medical Concept:** Angular conjunctivitis is characterized by inflammation specifically localized to the **angles of the eye** (lateral more common than medial canthus). It is classically caused by **Morax-Axenfeld bacillus** (*Moraxella lacunata*). The bacteria produce a proteolytic enzyme (protease) that macerates the skin and conjunctiva at the canthi. The association with **chronic alcoholism** is a high-yield clinical pointer. Alcoholics often suffer from **Pyridoxine (Vitamin B6) deficiency**, which predisposes the ocular epithelium to infection by *Moraxella*. The clinical presentation typically involves redness, excoriation of the skin at the outer canthus, and a "burning" sensation. **Why other options are incorrect:** * **Adenoviral conjunctivitis:** Typically presents with acute onset, watery discharge, and preauricular lymphadenopathy. It is usually diffuse rather than localized to the canthus. * **Apollo Disease (Acute Hemorrhagic Conjunctivitis):** Caused by Enterovirus 70 or Coxsackievirus A24. It presents with sudden onset, painful swelling, and characteristic subconjunctival hemorrhages. * **Trachoma:** Caused by *Chlamydia trachomatis* (Serotypes A, B, Ba, C). It primarily affects the superior palpebral conjunctiva, leading to follicles, Herbert’s pits, and eventual scarring (Arlt’s line). **High-Yield Clinical Pearls for NEET-PG:** * **Causative Organisms:** *Moraxella lacunata* (most common) and *Staphylococcus aureus*. * **Deficiency Link:** Often associated with **Vitamin B6 (Pyridoxine)** or **Zinc** deficiency. * **Treatment:** Topical **Zinc-based eye drops** (Zinc inhibits the proteolytic enzyme produced by Moraxella) and Oxytetracycline/Erythromycin ointment. * **Differential Diagnosis:** Always rule out **Blepharitis**, which involves the entire lid margin rather than just the angles.

Question 1

Which of the following is NOT a cause of tear film deficiency?

Accepted Answer

Systemic Vitamin C deficiency

Answer

Infiltrative disease of lacrimal glands

Answer

Post corneal transplant

Answer

Congenital absence of meibomian glands

Question 2

What is the term for a white plaque in the eye caused by vitamin A deficiency?

Accepted Answer

Bitot spot

Answer

Pink spot

Answer

White spot

Answer

Herald spot

Question 3

Which drug should be avoided in a case of spring catarrh?

Accepted Answer

Antibiotics

Answer

Methylcellulose eyedrops

Answer

Steroids

Answer

Antihistamine

Question 4

Which bacterium does NOT cause ophthalmia neonatorum?

Accepted Answer

Moraxella

Answer

Chlamydia

Answer

Gonococcus

Answer

Pseudomonas

Question 5

Which of the following conjunctivitis can also involve the intact cornea?

Accepted Answer

Acute purulent conjunctivitis

Answer

Acute mucopurulent conjunctivitis

Answer

Acute membranous conjunctivitis

Answer

Angular conjunctivitis

Question 6

Circumcorneal congestion is seen in all of the following conditions, EXCEPT:

Accepted Answer

Moraxella infection

Answer

Anterior uveitis

Answer

Acute congestive glaucoma

Answer

Stevens-Johnson syndrome

Question 7

What type of corneal ulcer is typically seen in Vernal keratoconjunctivitis?

Accepted Answer

Shield ulcer

Answer

Dendritic pattern

Answer

Pseudodendritic pattern

Answer

Geological ulcer

Question 8

In pterygium, which layer of the cornea is most commonly involved?

Accepted Answer

Bowman's layer

Answer

Epithelium

Answer

Endothelium

Answer

Descemet's membrane

Question 9

What is the most common cause of neonatal conjunctivitis?

Accepted Answer

Chlamydia

Answer

Chemical irritation

Answer

Gonococcus

Answer

Herpes simplex

Question 10

A chronic alcoholic complains of congestion around the lateral canthus and burning sensation with discomfort of the eyes. What is the probable diagnosis?

Accepted Answer

Angular conjunctivitis

Answer

Adenoviral conjunctivitis

Answer

Apollo Disease

Answer

Trachoma

Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva — MCQs

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