Ophthalmic Pharmacology — MCQs

Ophthalmic Pharmacology Indian Medical PG Practice Questions and MCQs

Question 211: The best local anesthetic for prolonged ophthalmic surgery requiring extended post-operative analgesia is:

A. Tetracaine
B. Procaine
C. Prilocaine
D. Bupivacaine (Correct Answer)

Explanation: ***Bupivacaine*** - **Bupivacaine** is an amide-type local anesthetic known for its **long duration of action** due to its high protein binding and lipid solubility. - This property makes it ideal for procedures requiring **prolonged analgesia**, such as extended ophthalmic surgery and post-operative pain control. *Tetracaine* - **Tetracaine** is an ester-type local anesthetic primarily used for **topical anesthesia**, especially in ophthalmology. - While effective for surface anesthesia, its duration of action is relatively short, making it unsuitable for prolonged surgical procedures requiring sustained nerve block. *Procaine* - **Procaine** is an ester-type local anesthetic with a **short duration of action** and is generally associated with a higher incidence of allergic reactions. - It is rarely used today for major regional blocks due to its limited potency and short effect, unlike the requirement for prolonged ophthalmic surgery. *Prilocaine* - **Prilocaine** is an amide-type local anesthetic with an **intermediate duration of action**. - Its use is limited in some cases due to its potential to cause **methemoglobinemia** at higher doses, making it less suitable for applications requiring extensive or prolonged regional anesthesia compared to bupivacaine.

Question 212: What is the drug of choice for treating intermediate uveitis?

A. Atropine
B. Antibiotics
C. Topical steroids
D. Systemic steroids (Correct Answer)

Explanation: ***Systemic steroids*** - **Systemic steroids** are the **drug of choice** for treating intermediate uveitis, especially when inflammation is significant or vision is threatened. - They effectively suppress the expansive **intraocular inflammation** typical of intermediate uveitis, which often involves the **vitreous** and **peripheral retina**. *Atropine* - **Atropine** is a **cycloplegic agent** primarily used to relieve ciliary spasm and prevent synechiae formation in anterior uveitis. - It does not address the underlying **inflammation** of intermediate uveitis, which is located more posteriorly. *Antibiotics* - **Antibiotics** are used to treat bacterial infections and are not indicated for **intermediate uveitis**, which is typically an **inflammatory** or **autoimmune disorder**. - They would be appropriate only if the uveitis were secondary to an **infectious cause**, which is not the primary characteristic of intermediate uveitis. *Topical steroids* - **Topical steroids** are effective for **anterior uveitis** but often fail to reach sufficient concentrations in the **vitreous** and **peripheral retina** to control the inflammation of intermediate uveitis. - **Intermediate uveitis** primarily affects the ciliary body, vitreous, and peripheral retina, requiring **systemic agents** for adequate therapeutic effect.

Question 213: Side effects of Pilocarpine include:

A. Cycloplegia
B. Decreased lacrimation
C. Mydriasis
D. Ciliary spasm (Correct Answer)

Explanation: ***Ciliary spasm*** - **Pilocarpine** is a **direct-acting cholinergic agonist** that stimulates muscarinic receptors, leading to **ciliary muscle contraction**. - This contraction causes **accommodation spasm** (ciliary spasm), resulting in blurry vision, particularly at a distance. *Decreased lacrimation* - **Pilocarpine** actually **increases lacrimation** (tear production) due to its parasympathomimetic effects on the lacrimal glands. - Decreased lacrimation would be an anticholinergic effect, the opposite of pilocarpine's action. *Cycloplegia* - **Cycloplegia** refers to the **paralysis of the ciliary muscle**, leading to loss of accommodation, and is caused by **anticholinergic agents**. - **Pilocarpine**, as a cholinergic agonist, causes **ciliary muscle contraction**, which is the opposite of cycloplegia. *Mydriasis* - **Mydriasis** is the **dilation of the pupil** and is caused by **sympathomimetics** or **anticholinergics**. - **Pilocarpine** causes **miosis** (pupil constriction) through the contraction of the iris sphincter muscle.

Question 214: Which medication is known to cause ptosis (eyelid drooping) as a side effect?

A. Amitriptyline (Correct Answer)
B. Levothyroxine
C. Epinephrine
D. Phenylephrine

Explanation: ***Amitriptyline*** - Amitriptyline is a **tricyclic antidepressant** that can cause anticholinergic side effects, including the **relaxation of Müller's muscle in the eyelid**, leading to **ptosis**. - This effect is due to its **alpha-adrenergic blocking properties**, which interfere with the sympathetic innervation of the eyelid muscles. *Phenylephrine* - Phenylephrine is an **alpha-1 adrenergic agonist**, meaning it would typically cause **pupil dilation (mydriasis)** and **eyelid elevation** by contracting Müller's muscle, not ptosis. - It is often used to treat nasal congestion and as an eye drop to **dilate pupils** or **reduce conjunctival redness**. *Epinephrine* - Epinephrine is a **potent adrenergic agonist** that stimulates both alpha and beta receptors. It would typically cause **eyelid retraction** and **pupil dilation** due to sympathetic activation, counteracting ptosis. - It is used in emergencies such as **anaphylaxis** and **cardiac arrest** due to its widespread systemic effects. *Levothyroxine* - Levothyroxine is a **synthetic thyroid hormone** used to treat hypothyroidism. Its side effects are generally related to hyperthyroidism if dosed improperly, such as **tachycardia**, **tremors**, and **heat intolerance**. - It does not directly affect the neuromuscular junction or sympathetic innervation of the eyelid in a way that would cause **ptosis**.

Question 215: Cyclosporine is used in the management of -

A. Disciform Keratitis (Correct Answer)
B. Phacomorphic glaucoma
C. Anterior Iridocyclitis
D. Rhegmatogenous retinal detachment

Explanation: ***Disciform Keratitis*** - **Cyclosporine** is an immunosuppressant particularly valuable in managing **disciform keratitis**, which represents immune-mediated stromal inflammation typically associated with herpes simplex virus (HSV). - In disciform keratitis, the primary pathology is **immune-mediated** rather than active viral replication, making cyclosporine an ideal therapeutic choice to suppress the inflammatory response while avoiding steroid dependency. - **Topical cyclosporine 0.05% or 1%** is specifically indicated for this condition and represents a **characteristic indication** in ophthalmic practice. *Anterior Iridocyclitis* - While cyclosporine may be used in **chronic, recurrent, or steroid-dependent anterior uveitis**, it is not a first-line agent for typical acute anterior iridocyclitis. - First-line management involves **topical corticosteroids** and **cycloplegics**; cyclosporine is reserved for refractory cases. - Disciform keratitis remains the more characteristic and commonly tested indication for cyclosporine in ophthalmology. *Rhegmatogenous retinal detachment* - **Rhegmatogenous retinal detachment** is a surgical emergency caused by a retinal tear allowing vitreous fluid into the subretinal space. - Management is **surgical** (scleral buckle, vitrectomy, or pneumatic retinopexy); immunosuppressants like cyclosporine have no role in this mechanical problem. *Phacomorphic glaucoma* - **Phacomorphic glaucoma** is secondary angle-closure glaucoma caused by an intumescent (swollen) lens pushing the iris forward. - Treatment involves **IOP control** followed by **cataract extraction**; cyclosporine has no role in this mechanical lens-induced condition.

Question 216: In a patient with acute anterior uveitis presenting with raised intraocular pressure, the PRIMARY treatment should be:

A. Topical steroids (Correct Answer)
B. Topical beta-blockers
C. Cycloplegics
D. Miotics

Explanation: ***Topical steroids*** - **Topical corticosteroids** are the primary treatment for **anterior uveitis** to reduce inflammation, which is the underlying cause of both the uveitis and often the raised IOP. - While IOP is elevated, managing the inflammation with steroids is crucial, as the inflammation itself can lead to secondary **IOP elevation** due to trabecular meshwork dysfunction or synechiae formation. *Topical beta-blockers* - **Topical beta-blockers** are used to lower intraocular pressure, but they do not address the underlying **inflammation** in acute anterior uveitis. - Using them alone without treating the inflammation can lead to progression of the uveitis and further ocular damage. *Cycloplegics* - **Cycloplegics** (e.g., atropine, cyclopentolate) are important adjuncts in acute anterior uveitis to relieve pain from ciliary spasm and prevent posterior synechiae formation by dilating the pupil. - They do not, however, treat the **inflammation** directly or primarily address the elevated intraocular pressure. *Miotics* - **Miotics** (e.g., pilocarpine) **constrict the pupil**, which can worsen symptoms in acute anterior uveitis by increasing ciliary body spasm and potentially increasing the risk of posterior synechiae formation. - They are contraindicated in acute anterior uveitis as they exacerbate pain and inflammation, and do not treat the underlying cause.

Question 217: Which among the following is the drug of choice for iridocyclitis?

A. Corticosteroids (anti-inflammatory) (Correct Answer)
B. Pilocarpine (miotic agent)
C. Atropine (mydriatic agent)
D. Timolol (beta-blocker)

Explanation: ***Corticosteroids (anti-inflammatory)*** - **Corticosteroids** are the drug of choice for iridocyclitis as they effectively suppress the **inflammation** within the iris and ciliary body. - They work by reducing the influx of inflammatory cells and inhibiting the production of inflammatory mediators, thereby alleviating pain, redness, and preventing complications like **posterior synechiae**. *Atropine (mydriatic agent)* - **Atropine** is a **mydriatic** (pupil-dilating) and cycloplegic agent used in iridocyclitis, but it is not the primary anti-inflammatory treatment. - Its role is to prevent the formation of **posterior synechiae** (adhesions between the iris and lens) and to relieve ciliary spasm, which reduces pain. *Pilocarpine (miotic agent)* - **Pilocarpine** is a **miotic** agent, meaning it constricts the pupil. - Pupil constriction is contraindicated in iridocyclitis as it can worsen pain and promote the formation of **posterior synechiae**. *Timolol (beta-blocker)* - **Timolol** is a **beta-blocker** primarily used to lower intraocular pressure in conditions like glaucoma. - While glaucoma can sometimes be a complication of severe iridocyclitis, timolol does not address the underlying **inflammation** of the iris and ciliary body, which is the primary pathology.

Practice by Chapter

Ocular Pharmacokinetics

Practice Questions

Anti-infective Agents

Practice Questions

Anti-inflammatory Drugs

Practice Questions

Antiglaucoma Medications

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Mydriatics and Cycloplegics

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Ocular Lubricants

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Anti-VEGF Agents

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Ocular Diagnostic Agents

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Anesthetics in Ophthalmology

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Preservatives and Their Effects

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Ocular Toxicology

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Novel Drug Delivery Systems

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