Diseases of the Conjunctiva Practice Questions

Q: Which of the following is NOT recommended for gonococcal eye prophylaxis?

Single-dose ceftriaxone 100mg/kg. **Explanation:** The question asks for the agent **NOT** recommended for prophylaxis of gonococcal ophthalmia neonatorum. **1. Why Option D is the Correct Answer:** Systemic antibiotics like **Ceftriaxone** are used for the **treatment** of established gonococcal conjunctivitis, not for routine prophylaxis. Furthermore, the dose mentioned (100 mg/kg) is incorrect and potentially dangerous; if systemic treatment is required for a neonate, the standard dose is 25–50 mg/kg (not to exceed 125 mg). Routine prophylaxis is strictly topical. **2. Analysis of Incorrect Options (Recommended Prophylactic Agents):** * **0.5% Erythromycin ointment (Option A):** Currently the most widely recommended prophylactic agent globally due to its efficacy and low incidence of chemical irritation. * **1% Silver Nitrate (Option B):** Historically known as **Credé’s Method**. While effective against *N. gonorrhoeae*, it is less commonly used today because it frequently causes transient **chemical conjunctivitis** and is ineffective against *Chlamydia*. * **1% Tetracycline ointment (Option C):** An acceptable alternative to erythromycin for topical prophylaxis in many clinical guidelines. **3. High-Yield Clinical Pearls for NEET-PG:** * **Ophthalmia Neonatorum Timing:** * *Chemical:* Within 24 hours. * *Gonococcal:* 2–5 days (Most destructive; can cause corneal perforation). * *Chlamydial:* 5–14 days (Most common cause overall). * **Management:** If a mother has an untreated gonococcal infection at delivery, the neonate should receive a **single prophylactic dose** of Ceftriaxone (25–50 mg/kg IM/IV), but this is "preventative treatment" for high-risk exposure, not standard universal eye prophylaxis. * **Prophylaxis Limitation:** Topical prophylaxis (Erythromycin/Silver Nitrate) prevents Gonococcal infection but is **not effective** in preventing Chlamydial ophthalmia.

Q: Follicular conjunctivitis is found in all of the following conditions EXCEPT:

Allergic conjunctivitis. **Explanation:** The core concept in differentiating conjunctival reactions lies in the pathological response of the subepithelial lymphoid tissue. **Follicles** are localized aggregations of lymphocytes (focal lymphoid hyperplasia) with a germinal center, appearing as pale, translucent, "rice-grain" elevations. **Papillae**, conversely, are vascular projections with a central vessel, typically seen in allergic and bacterial conditions. **Why Allergic Conjunctivitis is the correct answer:** Allergic conjunctivitis (such as Vernal Keratoconjunctivitis or Atopic Conjunctivitis) is characterized by a **papillary reaction**, not a follicular one. The hallmark is the "cobblestone" appearance of large papillae on the upper tarsal conjunctiva, driven by IgE-mediated mast cell degranulation. **Why the other options are incorrect:** * **Herpes Simplex Conjunctivitis:** Viral infections are the most common cause of follicular conjunctivitis. The virus acts as an antigen, stimulating the lymphoid tissue. * **Drug-induced Conjunctivitis:** Chronic use of topical medications (e.g., Brimonidine, Atropine, Pilocarpine, or preservatives like BAK) can cause a toxic/hypersensitivity follicular reaction. * **Adult Inclusion Conjunctivitis:** Caused by *Chlamydia trachomatis* (serotypes D-K), this is a classic cause of large, prominent follicles, especially in the inferior fornix. **High-Yield Clinical Pearls for NEET-PG:** * **Follicles = Viral, Chlamydial, or Toxic/Drug-induced.** * **Papillae = Allergic or Bacterial.** * **Trachoma (A-C):** Characterized by follicles on the *upper* tarsal conjunctiva (Herbert’s pits). * **Inclusion Conjunctivitis (D-K):** Characterized by follicles predominantly in the *lower* fornix. * **Exception:** Neonatal conjunctivitis (Ophthalmia Neonatorum) does **not** show follicles (even if Chlamydial) because the conjunctival lymphoid tissue does not develop until 3–6 weeks after birth.

Q: What is the commonest causative organism for angular conjunctivitis?

Moraxella axenfeld. **Explanation:** **Angular Conjunctivitis** is a specific type of chronic conjunctivitis characterized by inflammation localized to the angles of the eye (canthi). 1. **Why Moraxella axenfeld is correct:** The most common causative organism is **Moraxella axenfeld** (a Gram-negative diplobacillus). The pathogenesis involves the production of a **proteolytic enzyme** (protease) by the bacteria. This enzyme macerates and dissolves the epithelium of the bulbar conjunctiva and the skin at the inner and outer canthi, leading to the characteristic excoriation and redness. 2. **Why other options are incorrect:** * **Haemophilus influenzae:** While it is a common cause of acute mucopurulent conjunctivitis (especially in children), it is not the primary cause of the angular variety. However, *Haemophilus duplex* is occasionally implicated. * **Klebsiella pneumoniae:** This is typically associated with respiratory infections or rare cases of endogenous endophthalmitis, but it does not cause angular conjunctivitis. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Features:** Patients present with "redness at the corners," irritation, and a stringy discharge. The skin at the canthi appears excoriated and macerated. * **Treatment of Choice:** **Zinc oxide** or **Zinc sulphate** eye drops. Zinc acts by inhibiting the proteolytic enzyme produced by Moraxella, thereby allowing the epithelium to heal. * **Alternative Treatment:** Oxytetracycline or Erythromycin ointment can be used to eliminate the bacteria. * **Differential Diagnosis:** Angular blepharitis (often caused by *Staphylococcus aureus*).

Q: Circumcorneal congestion is not seen in which of the following conditions?

Acute bacterial conjunctivitis. **Explanation:** The key to answering this question lies in distinguishing between **superficial (conjunctival)** and **deep (ciliary/circumcorneal)** congestion. **1. Why Acute Bacterial Conjunctivitis is the correct answer:** In acute bacterial conjunctivitis, the inflammation is limited to the conjunctiva. The congestion is **superficial**, meaning the redness is most intense in the fornices and periphery, fading toward the limbus. The vessels are bright red, move with the conjunctiva, and blanch with 0.1% adrenaline. **Circumcorneal congestion (ciliary flush)**, however, involves the deep episcleral vessels surrounding the limbus and is a hallmark of intraocular or deep-seated inflammation. **2. Why the other options are incorrect:** * **Acute Iritis:** Inflammation of the iris involves the ciliary body. The ciliary vessels (branches of anterior ciliary arteries) become engorged, leading to a characteristic dusky-red circumcorneal flush. * **Acute Glaucoma:** A sudden rise in intraocular pressure causes significant ocular ischemia and inflammation, leading to intense ciliary congestion. * **Scleritis:** This is a deep-seated inflammation of the sclera. Because the deep episcleral plexus is involved, circumcorneal congestion is a prominent feature. **Clinical Pearls for NEET-PG:** * **Ciliary Flush:** Characterized by a violaceous/purplish hue, vessels do not move with the conjunctiva and do **not** blanch with adrenaline. * **The "Big Three" of Red Eye:** Always differentiate Acute Conjunctivitis (superficial) from Acute Iridocyclitis and Acute Angle Closure Glaucoma (deep/circumcorneal). * **Discharge:** Presence of mucopurulent discharge strongly points toward conjunctivitis, whereas its absence suggests deeper pathology.

Q: Deficiency of the mucin layer of the tear film occurs in which of the following conditions?

Keratoconjunctivitis sicca. **Explanation:** The tear film consists of three distinct layers: the **outer lipid layer** (meibomian glands), the **middle aqueous layer** (lacrimal glands), and the **inner mucin layer** (conjunctival goblet cells). **1. Why Keratoconjunctivitis Sicca (KCS) is correct:** KCS is a multifactorial disease of the ocular surface. While it is often associated with aqueous deficiency (Sjögren’s syndrome), it also involves significant damage to the conjunctival goblet cells. This leads to a **deficiency in the mucin layer**, which is essential for converting the hydrophobic corneal surface into a hydrophilic one, allowing the tear film to spread evenly. **2. Analysis of Incorrect Options:** * **Lacrimal gland removal:** This results in a pure **aqueous layer deficiency**, as the lacrimal gland is responsible for the bulk of water production. * **Canalicular block:** This causes **epiphora** (overflow of tears) due to an obstruction in the drainage system, rather than a deficiency in any tear film component. * **Herpetic keratitis:** This is a viral infection of the cornea. While it can cause secondary dry eye due to decreased corneal sensitivity (neurotrophic effect), it is not primarily defined by a mucin layer deficiency. **High-Yield Clinical Pearls for NEET-PG:** * **Mucin Layer Secretors:** Goblet cells (primary), Crypts of Henle, and Glands of Manz. * **Schirmer’s Test I:** Measures total tear secretion (Aqueous). <10mm in 5 mins is abnormal. * **Tear Film Break-up Time (TBUT):** The gold standard for assessing **mucin deficiency** and tear film stability. Normal is 15–35 seconds; <10 seconds indicates instability. * **Rose Bengal/Lissamine Green Stains:** Used to identify devitalized cells caused by mucin deficiency.

Q: Ligneous conjunctivitis is caused by:

Membranous conjunctivitis. **Explanation:** **Ligneous conjunctivitis** is a rare, chronic form of **membranous conjunctivitis** characterized by the formation of thick, firm, wood-like (ligneous) membranes on the palpebral conjunctiva. 1. **Why Membranous Conjunctivitis is correct:** The underlying pathophysiology involves a systemic **Type 1 Plasminogen deficiency**. This leads to impaired fibrinolysis, causing excessive fibrin deposition on mucous membranes. In the eye, this manifests as persistent, "woody" pseudomembranes or true membranes that recur rapidly if surgically removed. 2. **Why other options are incorrect:** * **Purulent conjunctivitis:** Typically caused by *N. gonorrhoeae*, it presents with profuse, thick pus but does not form organized, chronic woody membranes. * **Angular conjunctivitis:** Caused by *Moraxella lacunata*, it involves excoriation of the skin at the inner and outer canthi, not membrane formation. * **Phlyctenular conjunctivitis:** A type IV hypersensitivity reaction to endogenous toxins (like Tuberculoprotein), characterized by small, greyish-yellow nodules (phlyctens) near the limbus. **High-Yield Clinical Pearls for NEET-PG:** * **Pathognomonic Feature:** "Woody" consistency of the conjunctiva. * **Genetic Basis:** Autosomal recessive inheritance; mutation in the **PLG gene** (Plasminogen deficiency). * **Systemic Involvement:** Similar membranes can form in the mouth (gingiva), nasopharynx, and female genital tract. * **Treatment:** Topical heparin or concentrated plasminogen drops (surgical excision alone usually leads to aggressive recurrence).

Q: All are known to produce parenchymatous conjunctival xerosis except?

Vitamin A deficiency. ### Explanation To answer this question, it is essential to distinguish between the two types of conjunctival xerosis: **Epithelial** and **Parenchymatous**. **1. Why Vitamin A Deficiency is the Correct Answer:** Vitamin A deficiency (Xerophthalmia) causes **Epithelial Xerosis**. In this condition, the xerosis is a result of a lack of Vitamin A, which is essential for maintaining the health of the conjunctival epithelium and goblet cells. Crucially, the underlying conjunctival stroma (parenchyma) remains healthy, and there is **no scarring** of the sub-epithelial tissues. This is why the condition is reversible with Vitamin A supplementation. **2. Why the other options are incorrect (Parenchymatous Xerosis):** Parenchymatous xerosis occurs following **cicatrization (scarring)** of the conjunctiva, which leads to the destruction of goblet cells and the ducts of the lacrimal glands. * **Stevens-Johnson Syndrome (SJS):** A severe mucocutaneous reaction that leads to extensive conjunctival scarring and symblepharon. * **Trachoma:** Specifically Stage IV (healed trachoma), where cicatrization of the conjunctiva (Arlt’s line) leads to permanent structural damage. * **Diphtheric Membranous Conjunctivitis:** This is a necrotizing inflammation. The healing process involves extensive fibrosis and scarring of the conjunctival parenchyma. **Clinical Pearls for NEET-PG:** * **Bitot’s Spots:** Characteristic of Vitamin A deficiency; they are triangular, foamy patches found on the bulbar conjunctiva (usually temporal). * **Pemphigoid:** Another common cause of parenchymatous xerosis due to chronic cicatrization. * **Key Differentiator:** If the question mentions **scarring, symblepharon, or chemical burns**, think **Parenchymatous**. If it mentions **malnutrition or night blindness**, think **Epithelial**.

Q: Epidemic keratoconjunctivitis is caused by:

Adenovirus. **Explanation:** **Epidemic Keratoconjunctivitis (EKC)** is a highly contagious viral infection of the ocular surface. The correct answer is **Adenovirus**, specifically **serotypes 8, 19, and 37**. EKC is characterized by sudden onset follicular conjunctivitis, significant eyelid edema, and preauricular lymphadenopathy. A hallmark of this condition is the development of **multifocal subepithelial corneal infiltrates**, which are immune-mediated and can persist for months, causing blurred vision and glare. **Why other options are incorrect:** * **Neisseria gonorrhoeae:** Causes hyperacute purulent conjunctivitis, characterized by profuse "creamy" discharge and a high risk of rapid corneal perforation. * **Corynebacterium diphtheriae:** Known for causing **true membranous conjunctivitis**. It produces a thick, greyish-white membrane on the palpebral conjunctiva that bleeds upon peeling. * **Mycobacterium tuberculosis:** Rarely involves the conjunctiva; when it does, it typically presents as a chronic granulomatous conjunctivitis or a Parinaud oculoglandular syndrome, rather than an acute epidemic. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 8:** EKC is often associated with Adenovirus type 8; symptoms typically appear 8 days after exposure, and keratitis often appears 8 days after the onset of conjunctivitis. * **Transmission:** Highly contagious via respiratory droplets or contaminated fingers/ophthalmic instruments (e.g., tonometers). * **Pharyngoconjunctival Fever (PCF):** Also caused by Adenovirus (serotypes 3, 4, 7), but presents with a triad of fever, pharyngitis, and follicular conjunctivitis (more common in children). * **Management:** Primarily supportive (cold compresses, artificial tears). Steroids are reserved for visually significant subepithelial infiltrates.

Q: Which of the following is NOT true about phlyctenular conjunctivitis?

Allergens can be endogenous or exogenous.. ### Explanation **Phlyctenular Conjunctivitis** is an allergic nodular inflammation of the conjunctiva and cornea. Understanding its pathophysiology is crucial for NEET-PG. **1. Why Option B is the Correct Answer (The False Statement):** The allergens in phlyctenular conjunctivitis are strictly **endogenous** (internal to the body). The condition is a delayed hypersensitivity response to a protein to which the patient’s tissues have been previously sensitized. It is **not** caused by exogenous (external) allergens like pollen or dust. Historically, the most common endogenous allergen was *Mycobacterium tuberculosis*; however, currently, *Staphylococcus aureus* (from chronic blepharitis) is the most frequent cause. **2. Analysis of Other Options:** * **Option A:** It is indeed a **Type IV (Delayed) cell-mediated hypersensitivity** reaction. This distinguishes it from Vernal Keratoconjunctivitis (Type I). * **Option C:** Epidemiologically, the incidence is significantly **higher in girls** than in boys, typically affecting children and young adults (age 5–15 years). * **Option D:** The hallmark lesion is a **phlycten**—a small, pinkish-white nodule surrounded by a zone of hyperemia. These typically occur at or **near the limbus**. **3. Clinical Pearls for NEET-PG:** * **Triad of Symptoms:** Photophobia, lacrimation, and blepharospasm (especially severe if the cornea is involved). * **Fascicular Ulcer:** A characteristic "serpiginous" corneal ulcer that carries a leash of blood vessels behind it. * **Treatment:** Topical steroids are the mainstay for the ocular lesion, but treating the **underlying cause** (e.g., TB screening or treating Staphylococcal blepharitis) is mandatory to prevent recurrence. * **Differential Diagnosis:** Must be distinguished from Episcleritis (which blanches with adrenaline) and Pingueculitis.

Question 1

Which of the following is NOT recommended for gonococcal eye prophylaxis?

Accepted Answer

Single-dose ceftriaxone 100mg/kg

Answer

0.5% Erythromycin ophthalmic ointment

Answer

1% silver nitrate ophthalmic ointment

Answer

1% tetracycline ophthalmic ointment

Question 2

Follicular conjunctivitis is found in all of the following conditions EXCEPT:

Accepted Answer

Allergic conjunctivitis

Answer

Herpes simplex conjunctivitis

Answer

Drug-induced conjunctivitis

Answer

Adult inclusion conjunctivitis

Question 3

What is the commonest causative organism for angular conjunctivitis?

Accepted Answer

Moraxella axenfeld

Answer

Haemophilus influenzae

Answer

Klebsiella pneumoniae

Answer

None of the above

Question 4

Circumcorneal congestion is not seen in which of the following conditions?

Accepted Answer

Acute bacterial conjunctivitis

Answer

Acute iritis

Answer

Acute glaucoma

Answer

Scleritis

Question 5

A 19-year-old woman presents with recurrent conjunctivitis occurring annually in early summer and lasting for approximately six weeks. Which of the following is the most appropriate drug for this condition?

Accepted Answer

Antazoline

Answer

Atropine

Answer

Pilocarpine

Answer

Phenylephrine

Question 6

Deficiency of the mucin layer of the tear film occurs in which of the following conditions?

Accepted Answer

Keratoconjunctivitis sicca

Answer

Lacrimal gland removal

Answer

Canalicular block

Answer

Herpetic keratitis

Question 7

Ligneous conjunctivitis is caused by:

Accepted Answer

Membranous conjunctivitis

Answer

Purulent conjunctivitis

Answer

Angular conjunctivitis

Answer

Phlyctenular conjunctivitis

Question 8

All are known to produce parenchymatous conjunctival xerosis except?

Accepted Answer

Vitamin A deficiency

Answer

Stevens-Johnson syndrome

Answer

Trachoma

Answer

Diphtheric membranous conjunctivitis

Question 9

Epidemic keratoconjunctivitis is caused by:

Accepted Answer

Adenovirus

Answer

Neisseria gonorrhoeae

Answer

Corynebacterium diphtheriae

Answer

Mycobacterium tuberculosis

Question 10

Which of the following is NOT true about phlyctenular conjunctivitis?

Accepted Answer

Allergens can be endogenous or exogenous.

Answer

It is a Type IV cell-mediated hypersensitivity reaction.

Answer

The incidence is higher in girls than in boys.

Answer

Nodular lesions typically occur near the limbus.

Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva — MCQs

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