Ophthalmic Pharmacology — MCQs

Ophthalmic Pharmacology Indian Medical PG Practice Questions and MCQs

Question 161: Mitomycin C drops are used in:

A. Pterygium (Correct Answer)
B. Ophthalmia nodosa
C. Spring catarrh
D. Dry eye

Explanation: **Explanation:** **Mitomycin C (MMC)** is a potent alkylating agent derived from *Streptomyces caespitosus*. It acts as an antimetabolite by inhibiting DNA synthesis, thereby suppressing the proliferation of fibroblasts and vascular endothelial cells. **Why Pterygium is Correct:** In Pterygium surgery, the main challenge is the high rate of recurrence. MMC is used as an adjunct (either intraoperatively or as postoperative drops) to inhibit the proliferation of subconjunctival fibroblasts. This significantly reduces the risk of recurrence after excision. It is also commonly used in Glaucoma filtration surgery (Trabeculectomy) to prevent bleb fibrosis. **Why Other Options are Incorrect:** * **Ophthalmia nodosa:** This is a granulomatous inflammatory reaction caused by caterpillar hairs. Treatment involves surgical removal of the hairs and topical steroids, not antimetabolites. * **Spring catarrh (VKC):** This is an allergic condition. Management involves mast cell stabilizers, antihistamines, and steroids. MMC has no role in treating allergic hypersensitivity. * **Dry eye:** MMC is actually a potential *cause* of ocular surface toxicity and can worsen dry eye symptoms. Treatment involves lubricants, cyclosporine, or punctal plugs. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Cross-links DNA (alkylating agent). * **Other Ophthalmic Uses:** Trabeculectomy (to increase success rate), Ocular Surface Squamous Neoplasia (OSSN), and preventing haze after PRK (Refractive surgery). * **Side Effects:** Scleral thinning, melting, and delayed wound healing. * **Alternative in Pterygium:** The "Gold Standard" for reducing recurrence is currently **Conjunctival Autograft (CAG)**, often preferred over MMC due to fewer long-term complications.

Question 162: Which drug was used for noninfectious uveitis in the LUMINATE clinical trial program?

A. Steroid/Infliximab
B. Cyclosporin
C. Methotrexate
D. Voclosporin (Correct Answer)

Explanation: **Explanation:** **Voclosporin** is a novel, potent **calcineurin inhibitor (CNI)**. The **LUMINATE** (LUMINous non-infectious uveitis Active and non-acTivE) clinical trial program specifically investigated the efficacy and safety of voclosporin in patients with non-infectious uveitis (including posterior, intermediate, and panuveitis). Voclosporin works by inhibiting T-cell activation through the calcineurin pathway, similar to Cyclosporine but with a more predictable pharmacokinetic profile and increased potency. While it showed promise in trials, it is currently more widely recognized for its FDA approval in treating lupus nephritis. **Analysis of Incorrect Options:** * **A. Steroid/Infliximab:** While corticosteroids are first-line for uveitis and Infliximab (TNF-α inhibitor) is used for refractory cases (e.g., Behçet’s disease), they were not the primary drugs studied in the LUMINATE trials. * **B. Cyclosporin:** This is a first-generation CNI used in uveitis. Although Voclosporin is a structural analogue of Cyclosporine, the specific "LUMINATE" branding belongs to the newer molecule. * **C. Methotrexate:** This is a common antimetabolite used as a steroid-sparing agent in chronic uveitis, but it was not the subject of the LUMINATE program. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Voclosporin binds to cyclophilin A, inhibiting calcineurin and preventing the dephosphorylation of **NFAT** (Nuclear Factor of Activated T-cells). * **Key Trial Name:** Associate **LUMINATE** with **Voclosporin** and **Uveitis**. * **Drug of Choice:** For non-infectious uveitis, **Corticosteroids** remain the mainstay of acute treatment, while **Adalimumab** is the first non-steroidal systemic drug FDA-approved for non-infectious intermediate, posterior, and panuveitis (VISUAL trials).

Question 163: Chloroquine retinopathy risk is high in all patients except?

A. Total cumulative dose greater than 460 g
B. Daily dose greater than 3 mg/kg or 250 mg/day
C. Patients with kidney dysfunction
D. Intake for more than 2 years (Correct Answer)

Explanation: **Explanation:** The risk of chloroquine (CQ) and hydroxychloroquine (HCQ) retinopathy is primarily determined by the **cumulative dose** and **duration of exposure**. According to the American Academy of Ophthalmology (AAO) guidelines, the risk of toxicity is very low during the first 5 years of treatment. Therefore, intake for only **2 years** is not considered a high-risk factor; the risk significantly increases only after **5 years** of continuous use. **Analysis of Options:** * **Option A (Cumulative dose > 460 g):** This is a major risk factor. For Chloroquine, a cumulative dose exceeding 460 g (or >1000 g for Hydroxychloroquine) significantly increases the likelihood of retinal damage. * **Option B (Daily dose > 3 mg/kg):** High daily dosing is the most significant predictor of toxicity. For CQ, the safe limit is **<2.3 mg/kg** of real body weight. A dose >3 mg/kg is a high-risk factor. (For HCQ, the limit is <5.0 mg/kg). * **Option C (Kidney dysfunction):** Chloroquine is cleared by the kidneys. In patients with renal insufficiency (Stage 3 or worse), the drug's half-life increases, leading to higher systemic levels and a higher risk of deposition in the RPE. * **Option D (Correct):** As stated, toxicity is rare before 5 years of use. Thus, 2 years is insufficient duration to be categorized as "high risk." **Clinical Pearls for NEET-PG:** * **Classic Sign:** "Bull’s Eye Maculopathy" (granular pigmentary changes at the fovea surrounded by a depigmented zone). * **Earliest Sign:** Fine granular pigmentary changes in the macula. * **Screening:** Baseline exam followed by annual screening after 5 years. * **Tests:** 10-2 Visual Fields (VF) and SD-OCT are the gold standards for screening. * **Mechanism:** Chloroquine binds to melanin in the Retinal Pigment Epithelium (RPE), causing metabolic damage to photoreceptors.

Question 164: Which of the following agents does not affect near vision?

A. Atropine
B. Adrenaline (Correct Answer)
C. Homatropine
D. Pilocarpine

Explanation: To answer this question, we must understand the mechanism of **accommodation**, which is the eye's ability to focus on near objects. This process is controlled by the **ciliary muscle** (innervated by parasympathetic fibers). ### Why Adrenaline is the Correct Answer **Adrenaline (Option B)** is a sympathomimetic agent. It acts primarily on the dilator pupillae muscle (alpha-1 receptors) to cause mydriasis (pupillary dilation). Crucially, the ciliary muscle has negligible adrenergic innervation compared to its parasympathetic supply. Therefore, Adrenaline does not cause paralysis of the ciliary muscle (cycloplegia) or excessive contraction (spasm). Since it does not affect the ciliary muscle, **near vision remains intact.** ### Why Other Options are Incorrect * **Atropine (Option A) & Homatropine (Option C):** These are parasympatholytic (anticholinergic) agents. They block the M3 receptors on the ciliary muscle, leading to **cycloplegia** (paralysis of accommodation). This makes it impossible for the eye to focus on near objects, causing blurred near vision. Atropine is long-acting (7–10 days), while Homatropine is intermediate-acting. * **Pilocarpine (Option D):** This is a parasympathomimetic (miotic) agent. It causes **spasm of accommodation** by overstimulating the ciliary muscle. This shifts the refractive state toward myopia, making distant vision blurry and often causing "brow ache" or fluctuating near vision. ### High-Yield Clinical Pearls for NEET-PG * **Mydriatics vs. Cycloplegics:** All cycloplegics are mydriatics (e.g., Atropine), but not all mydriatics are cycloplegics (e.g., Adrenaline, Phenylephrine). * **Phenylephrine:** Like Adrenaline, it is a pure mydriatic and **does not** affect near vision. It is often used in clinical practice to dilate the pupil while sparing accommodation. * **Drug of Choice:** Atropine is the strongest cycloplegic and is the drug of choice for refraction in children under 7 years (due to their high accommodative tone).

Question 165: In anterior uveitis with secondary glaucoma, which of the following mydriatics should not be given?

A. Pilocarpine (Correct Answer)
B. Homatropine
C. Epinephrine
D. Tropicamide

Explanation: In **Anterior Uveitis**, the primary goals of treatment are to reduce inflammation, prevent the formation of synechiae, and provide pain relief by relieving ciliary muscle spasm. ### Why Pilocarpine is Contraindicated (The Correct Answer) Pilocarpine is a **miotic** (parasympathomimetic). It is strictly contraindicated in anterior uveitis for two main reasons: 1. **Blood-Aqueous Barrier Breakdown:** It increases vascular permeability, which worsens intraocular inflammation and increases the protein content in the aqueous humor. 2. **Synechiae Formation:** By constricting the pupil, it increases the surface area of contact between the iris and the lens, promoting the formation of **posterior synechiae**. This can lead to pupillary block and worsen secondary glaucoma. 3. **Ciliary Spasm:** It causes contraction of the ciliary muscle, significantly increasing the patient's pain. ### Why the Other Options are Incorrect * **Homatropine & Tropicamide:** These are **cycloplegic-mydriatics**. They are the drugs of choice in uveitis because they put the ciliary body at rest (reducing pain) and dilate the pupil to prevent or break posterior synechiae. * **Epinephrine:** While not a primary treatment for uveitis, it is a sympathomimetic that causes mydriasis without increasing inflammation or causing ciliary spasm. ### NEET-PG High-Yield Pearls * **Drug of Choice for Uveitis:** Atropine 1% (strongest cycloplegic) is preferred to maintain a dilated pupil and prevent synechiae. * **Secondary Glaucoma in Uveitis:** Usually managed with aqueous suppressants (Beta-blockers or Carbonic Anhydrase Inhibitors). * **Avoid Latanoprost:** Like Pilocarpine, Prostaglandin analogues (Latanoprost) are generally avoided in uveitis as they are pro-inflammatory.

Question 166: Which of the following medications should not be used in a patient with elevated intraocular pressure associated with uveitis?

A. Timolol
B. Pilocarpine (Correct Answer)
C. Atropine
D. Acetazolamide

Explanation: **Explanation:** In patients with **uveitis-induced ocular hypertension** (inflammatory glaucoma), the primary goal is to control inflammation and lower intraocular pressure (IOP) without exacerbating the underlying pathology. **Why Pilocarpine is contraindicated:** Pilocarpine is a miotic (cholinergic agonist). It is strictly avoided in uveitis for three main reasons: 1. **Breakdown of Blood-Aqueous Barrier:** It increases vascular permeability, worsening the intraocular inflammation. 2. **Formation of Synechiae:** By causing miosis (pupillary constriction), it increases the surface area of contact between the iris and the lens, promoting the formation of **posterior synechiae**. 3. **Ciliary Muscle Spasm:** It induces contraction of the ciliary muscle, which significantly increases pain and photophobia in an already inflamed eye. **Analysis of Incorrect Options:** * **Timolol (Beta-blocker):** A first-line agent to reduce aqueous production. It does not affect pupil size or the blood-aqueous barrier, making it safe for uveitic glaucoma. * **Atropine (Mydriatic-Cycloplegic):** Actually indicated in uveitis. It prevents synechiae by dilating the pupil and relieves "ciliary spasm" pain by paralyzing the ciliary muscle. * **Acetazolamide (Carbonic Anhydrase Inhibitor):** A systemic drug that reduces aqueous humor secretion. It is highly effective for rapid IOP reduction in inflammatory glaucoma. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Uveitis:** Topical Steroids (to control inflammation) + Cycloplegics like Atropine or Homatropine. * **Avoid in Uveitis:** Pilocarpine (miotics) and Prostaglandin analogues (like Latanoprost), as both can worsen inflammation or macular edema. * **Triple Effect of Atropine in Uveitis:** 1. Provides rest to the iris/ciliary body; 2. Prevents/breaks synechiae; 3. Reduces pain.

Question 167: Bull's eye retinal lesion is seen in toxic retinopathy due to:

A. Lead
B. Ethambutol
C. Chloroquine (Correct Answer)
D. Oral contraceptive pills

Explanation: **Explanation:** **Chloroquine (and Hydroxychloroquine)** are the classic causes of **Bull’s eye maculopathy**. The underlying mechanism involves the drug binding to melanin in the Retinal Pigment Epithelium (RPE). This leads to a circular area of RPE atrophy and depigmentation surrounding a central spared foveolar island, creating the characteristic "Bull's eye" appearance on fundoscopy. On Fluorescein Angiography (FFA), this appears as a "window defect." **Analysis of Incorrect Options:** * **Lead:** Chronic lead poisoning (Plumbism) typically causes optic atrophy or papilledema due to increased intracranial pressure, rather than specific macular pigmentary changes. * **Ethambutol:** This antitubercular drug is notorious for causing **Retrobulbar Neuritis**. It manifests as a decrease in visual acuity and red-green color blindness, but not a Bull's eye lesion. * **Oral Contraceptive Pills (OCPs):** These are associated with vascular complications such as Central Retinal Vein Occlusion (CRVO) or Retinal Artery Occlusion due to their pro-thrombotic nature, but not toxic retinopathy. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis for Bull's Eye Maculopathy:** Chloroquine/Hydroxychloroquine toxicity, Stargardt’s disease, Cone-rod dystrophy, and Benign concentric macular dystrophy. * **Screening:** The most sensitive tests for early detection of toxicity are **Spectral Domain Optical Coherence Tomography (SD-OCT)** (showing the "Flying Saucer" sign) and **Automated Visual Fields (10-2)**. * **Dosage:** Toxicity risk increases significantly when the cumulative dose of Chloroquine exceeds 300g or Hydroxychloroquine exceeds 5.0 mg/kg of real body weight.

Question 168: Combination of pilocarpine and epinephrine use in glaucoma treatment may inhibit which of the following?

A. Pigmented pupillary cyst (Correct Answer)
B. Retinal detachment
C. Vitreous haemorrhage
D. Iridocyclitis

Explanation: **Explanation:** The correct answer is **A. Pigmented pupillary cyst.** **Mechanism of Action:** Pilocarpine is a direct-acting parasympathomimetic (miotic) used in glaucoma. A known side effect of long-term miotic therapy, particularly with potent agents like echothiophate or high-dose pilocarpine, is the formation of **pigmented iris epithelial cysts** at the pupillary margin. These cysts occur due to the constant mechanical stimulation and proliferation of the iris pigment epithelium. **Epinephrine**, a sympathomimetic, acts as a physiological antagonist to the miotic effect of pilocarpine. When used in combination, epinephrine causes a mild counter-dilation (mydriasis) or stabilizes the iris pigment epithelium, thereby **inhibiting or preventing** the formation of these pupillary cysts. **Analysis of Incorrect Options:** * **B. Retinal detachment:** Pilocarpine actually *increases* the risk of retinal detachment due to the forward displacement of the lens-iris diaphragm and traction on the peripheral retina/vitreous base. Epinephrine does not prevent this. * **C. Vitreous haemorrhage:** This is not a standard complication of pilocarpine therapy, nor is it mitigated by this specific drug combination. * **D. Iridocyclitis:** While miotics can cause a breakdown of the blood-aqueous barrier leading to mild inflammation (miotic iritis), the specific "inhibition" mentioned in classic pharmacological texts refers to the structural prevention of iris cysts. **High-Yield NEET-PG Pearls:** * **Iris Cysts:** Most commonly seen with long-acting cholinesterase inhibitors (e.g., Echothiophate). Phenylephrine or Epinephrine drops can prevent them. * **Pilocarpine Side Effects:** Accommodative spasm (brow ache), miosis (poor night vision), and increased risk of retinal tears. * **Adrenaline (Epinephrine) in Glaucoma:** It is contraindicated in narrow-angle glaucoma as it can precipitate angle closure due to its mydriatic effect. It also causes **Cystoid Macular Edema (CME)** in aphakic patients.

Question 169: What is the drug of choice for Spring Catarrh?

A. Topical Steroids
B. Palivizumab
C. Olopatadine (Correct Answer)
D. Sodium chromoglycate

Explanation: **Explanation:** **Spring Catarrh**, also known as **Vernal Keratoconjunctivitis (VKC)**, is a bilateral, recurrent, external ocular inflammation primarily affecting young males in hot, dry climates. It is a Type I (IgE-mediated) and Type IV hypersensitivity reaction. **Why Olopatadine is the Correct Answer:** Modern management of VKC prioritizes drugs with **dual action**. Olopatadine acts as both a **potent H1-receptor antagonist** and a **mast cell stabilizer**. This dual mechanism provides rapid symptomatic relief from itching while preventing further degranulation of mast cells. It is currently considered the first-line maintenance therapy (Drug of Choice) due to its superior efficacy and better dosing profile (twice daily) compared to older agents. **Analysis of Incorrect Options:** * **Topical Steroids (Option A):** While steroids are the most effective for controlling acute "exacerbations" or "pulses," they are **not** the drug of choice for long-term management due to the high risk of sight-threatening side effects like steroid-induced glaucoma and cataracts. * **Palivizumab (Option B):** This is a monoclonal antibody used for the prevention of Respiratory Syncytial Virus (RSV) in infants; it has no role in ophthalmology. * **Sodium Chromoglycate (Option C):** This is a pure mast cell stabilizer. It has a slow onset of action (takes 5–10 days to work) and requires frequent dosing (4 times daily), making it less effective than dual-action agents like Olopatadine. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark signs:** Cobblestone papillae (Palpebral form) and Horner-Trantas dots (Limbal form). * **Shield Ulcer:** A sterile, indolent oval ulcer seen in the upper cornea in severe VKC. * **Refractory cases:** If dual-action drugs fail, topical **Cyclosporine** or **Tacrolimus** are used as steroid-sparing agents.

Question 170: Which of the following arachidonic acid derivatives is used in the treatment of glaucoma?

A. Latanoprost (Correct Answer)
B. Iloprost
C. Alprostadil
D. None of the above

Explanation: **Explanation:** **Latanoprost** is the correct answer because it is a synthetic **Prostaglandin F2-alpha (PGF2α) analogue**. In the management of glaucoma, PGF2α analogues are considered first-line agents. They work by increasing the **uveoscleral outflow** of aqueous humor, thereby reducing intraocular pressure (IOP). **Analysis of Options:** * **Latanoprost (Option A):** A PGF2α derivative. It is highly effective, requires only once-daily dosing, and has a superior IOP-lowering effect compared to many beta-blockers. * **Iloprost (Option B):** A synthetic analogue of **Prostacyclin (PGI2)**. It acts as a potent vasodilator and inhibitor of platelet aggregation. It is primarily used in the treatment of pulmonary arterial hypertension and Raynaud's phenomenon, not glaucoma. * **Alprostadil (Option C):** A synthetic form of **Prostaglandin E1 (PGE1)**. Its clinical uses include maintaining the patency of the ductus arteriosus in newborns and treating erectile dysfunction. It does not have a role in glaucoma management. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** PGF2α analogues reduce IOP by remodeling the extracellular matrix in the ciliary muscle, enhancing the uveoscleral (non-conventional) pathway. * **Side Effects (High Yield):** 1. **Hypertrichosis:** Increased length and thickness of eyelashes (Bimatoprost is specifically used for this in Latisse). 2. **Iris Pigmentation:** Permanent darkening of the iris (heterochromia) due to increased melanin in melanocytes. 3. **Cystoid Macular Edema (CME):** Can occur in aphakic or pseudophakic patients. 4. **Prostaglandin-associated Periorbitopathy:** Loss of periorbital fat leading to a "sunken eye" appearance. * **Contraindication:** Active intraocular inflammation (uveitis), as prostaglandins are pro-inflammatory mediators.

Practice by Chapter

Ocular Pharmacokinetics

Practice Questions

Anti-infective Agents

Practice Questions

Anti-inflammatory Drugs

Practice Questions

Antiglaucoma Medications

Practice Questions

Mydriatics and Cycloplegics

Practice Questions

Ocular Lubricants

Practice Questions

Anti-VEGF Agents

Practice Questions

Ocular Diagnostic Agents

Practice Questions

Anesthetics in Ophthalmology

Practice Questions

Preservatives and Their Effects

Practice Questions

Ocular Toxicology

Practice Questions

Novel Drug Delivery Systems

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free