Mydriatics and Cycloplegics — MCQs
Atropine is the drug of choice in –
In head injury, unilateral dilatation of the pupil is seen due to?
Which of the following is a contraindication to topical steroids?
Atropine is substituted by phenylephrine to facilitate fundus examination when?
Which of the following is the prototypical sympathomimetic agent with both alpha and beta-adrenergic activity?
Cycloplegics are used for the treatment of:
Which of the following drugs is not used in treatment of iridocyclitis:
A mother reports that her daughter ingested a substance in an unknown dose. The girl presents with hypertension, tachycardia, mydriasis, and hyperthermia. What is the most likely substance?
Primary objective of the use of atropine in anterior uveitis
1% atropine is given in uveitis to:
Mydriatics and Cycloplegics Indian Medical PG Practice Questions and MCQs
Question 1: Atropine is the drug of choice in –
- A. Chorioretinitis
- B. Lens induced glaucoma
- C. Iridocyclitis (Correct Answer)
- D. Closed angle glaucoma
Explanation: ***Iridocyclitis*** - Atropine is a **potent cycloplegic and mydriatic agent** often used in iridocyclitis to **relax the ciliary body muscles** and prevent the formation of posterior synechiae. - Its **long-acting effect** helps in reducing pain, inflammation, and preventing complications such as iris bombe by keeping the pupil dilated. *Chorioretinitis* - This condition primarily affects the **choroid and retina**, and while inflammation may be present, systemic or topical **corticosteroids** are typically the primary treatment. - Atropine is not indicated as a primary treatment for the inflammation itself in chorioretinitis, as its main action is on the iris and ciliary body. *Lens induced glaucoma* - The definitive treatment for lens-induced glaucoma, such as **phacomorphic glaucoma** or **phacolytic glaucoma**, is surgical removal of the cataractous lens. - Atropine would cause mydriasis, which can paradoxically worsen some forms of glaucoma by blocking the drainage angle, especially in cases of angle closure [1] [2]. *Closed angle glaucoma* - Atropine, being a mydriatic, would **dilate the pupil** and potentially exacerbate closed-angle glaucoma by further **crowding the anterior chamber angle** and blocking aqueous humor outflow [3]. - The focus in closed-angle glaucoma is to constrict the pupil (with miotics like pilocarpine) and reduce intraocular pressure.
Question 2: In head injury, unilateral dilatation of the pupil is seen due to?
- A. Ophthalmic N. compression
- B. Trigeminal N. compression
- C. Oculomotor nerve compression (Correct Answer)
- D. None of the options
Explanation: Oculomotor nerve compression - Unilateral pupillary dilation, often referred to as a **blown pupil**, is a classic sign of **oculomotor nerve (CN III) compression** due to increased intracranial pressure, typically from a **herniating uncus** [1]. - The parasympathetic fibers responsible for pupillary constriction run on the superficial aspect of the oculomotor nerve and are thus vulnerable to extrinsic compression [1], [2]. *Ophthalmic N. compression* - The **ophthalmic nerve (CN V1)** is a sensory nerve responsible for sensation to the forehead, scalp, upper eyelid, and cornea, not pupillary control. - Compression of this nerve would cause **sensory deficits** in its distribution and potentially abolish the **corneal reflex**, but not pupillary dilation. *Trigeminal N. compression* - The **trigeminal nerve (CN V)** is primarily responsible for sensation to the face and motor control of the muscles of mastication. - Compression would lead to **facial numbness or pain** and **weakness in chewing**, with no direct impact on pupillary size. *None of the options* - This option is incorrect because oculomotor nerve compression is a well-established cause of unilateral pupillary dilation in head injuries [1].
Question 3: Which of the following is a contraindication to topical steroids?
- A. Dendritic ulcer (Correct Answer)
- B. Herpetic stromal keratitis without epithelial defect
- C. Elevated intraocular pressure
- D. Non-infectious anterior uveitis
Explanation: ***Dendritic ulcer*** - A **dendritic ulcer** is characteristic of **herpes simplex keratitis**, which is an active viral infection of the cornea. - **Topical steroids** are contraindicated because they can suppress the immune response, leading to viral replication, corneal melt, and potentially severe vision loss or perforation. *Herpetic stromal keratitis without epithelial defect* - In cases of **stromal keratitis**, where the infection is deeper and an intact epithelium is present, topical steroids may be used cautiously in conjunction with antiviral agents to reduce inflammation and scarring. - The primary concern with steroids in herpes simplex keratitis is activating viral replication in the presence of an **epithelial defect**, which is not present here. *Elevated intraocular pressure* - **Elevated intraocular pressure** is a known side effect of topical steroid use, especially with prolonged administration, but it is not an absolute contraindication in itself. - It necessitates careful monitoring and may require concurrent glaucoma treatment, but the primary condition needing steroids may still warrant their use. *Non-infectious anterior uveitis* - **Topical corticosteroids** are the **mainstay of treatment** for non-infectious anterior uveitis to reduce inflammation and prevent complications such as synechiae and vision loss. - The benefits of controlling inflammation in uveitis generally outweigh the risks associated with judicious steroid use.
Question 4: Atropine is substituted by phenylephrine to facilitate fundus examination when?
- A. Mydriasis required without cycloplegia (Correct Answer)
- B. Cycloplegia and mydriasis both are not required
- C. Mydriasis and cycloplegia both required
- D. Cycloplegia is required
Explanation: ***Mydriasis required without cycloplegia*** - Phenylephrine is a **sympathomimetic** drug that causes **mydriasis (pupil dilation)** by stimulating alpha-1 adrenergic receptors in the iris dilator muscle. - Unlike atropine, phenylephrine has no significant effect on the ciliary muscle, thus it causes minimal to no **cycloplegia (paralysis of accommodation)**, which is ideal if only pupillary dilation is needed for fundus examination without affecting the patient's ability to focus. *Cycloplegia and mydriasis both are not required* - If neither mydriasis nor cycloplegia is required, there would be no need to use phenylephrine or atropine, as the goal is to *facilitate* fundus examination, which typically requires dilation. - This option is incorrect because the question implies a situation where a drug is *substituted* for atropine, indicating a specific need. *Mydriasis and cycloplegia both required* - If both mydriasis and cycloplegia are required, atropine would be the more appropriate choice as it is a potent cycloplegic in addition to being a strong mydriatic. - Phenylephrine does not provide sufficient cycloplegia to meet this requirement. *Cycloplegia is required* - Phenylephrine is a **poor cycloplegic**; its primary action is mydriasis. - If cycloplegia is the main requirement (e.g., for **refraction in children**), drugs like atropine or cyclopentolate would be preferred.
Question 5: Which of the following is the prototypical sympathomimetic agent with both alpha and beta-adrenergic activity?
- A. Epinephrine (Correct Answer)
- B. Isoproterenol
- C. Norepinephrine
- D. Dopamine
Explanation: ***Epinephrine*** - Epinephrine (adrenaline) is a potent direct-acting **sympathomimetic** that stimulates both **alpha and beta-adrenergic receptors**. - Its diverse effects on the cardiovascular, respiratory, and other systems make it the prototypical agent for demonstrating both receptor activities. *Norepinephrine* - While norepinephrine (noradrenaline) also acts on **alpha and beta-1 receptors**, its affinity for **beta-2 receptors** is significantly lower than epinephrine. - This results in a predominant effect on **vasoconstriction** and cardiac contractility rather than bronchodilation or peripheral vasodilation. *Isoproterenol* - Isoproterenol is a **non-selective beta-adrenergic agonist**, meaning it primarily stimulates **beta-1 and beta-2 receptors**. - It has minimal or no activity at **alpha-adrenergic receptors**, differentiating it from epinephrine's mixed activity. *Dopamine* - Dopamine's effects are **dose-dependent**; at low doses, it primarily stimulates **dopamine receptors** and at moderate doses, it activates **beta-1 receptors**. - At high doses, it can stimulate **alpha-adrenergic receptors**, but its primary and distinguishing characteristic is its agonism at **dopamine receptors**, which epinephrine does not share.
Question 6: Cycloplegics are used for the treatment of:
- A. Lens-induced glaucoma
- B. Closed-angle glaucoma
- C. Iridocyclitis (Correct Answer)
- D. Chorioretinitis
Explanation: ***Iridocyclitis*** - **Cycloplegics** paralyze the **ciliary muscle** and **iris sphincter**, reducing spasm and pain associated with inflammation in iridocyclitis. - They also help prevent the formation of **posterior synechiae**, adhesions between the iris and the lens. - This is the **primary therapeutic indication** for cycloplegics in inflammatory conditions. *Lens-induced glaucoma* - This condition is caused by **lens swelling** or **leakage of lens material**, leading to elevated intraocular pressure. - Treatment typically involves **surgical removal of the cataractous lens**, not cycloplegics. *Closed-angle glaucoma* - Cycloplegics are **CONTRAINDICATED** in closed-angle glaucoma as they cause **pupillary dilation**, which can precipitate or worsen angle closure. - The condition is characterized by **blockage of aqueous humor outflow** due to the iris obstructing the trabecular meshwork. - Treatment involves methods to open the angle, such as **laser iridotomy** or medications that **constrict the pupil** (miotics) or reduce aqueous humor production. *Chorioretinitis* - This is an **inflammation of the choroid and retina**, layers located at the back of the eye (posterior segment). - Treatment primarily involves **systemic anti-inflammatory agents** and antimicrobials if infectious. - Cycloplegics do not directly address posterior segment inflammation, though they may be used for symptomatic relief if anterior chamber reaction is present.
Question 7: Which of the following drugs is not used in treatment of iridocyclitis:
- A. Pilocarpine eye drops
- B. Atropine eye ointment
- C. Steroid eye drops
- D. Timolol eye drops (Correct Answer)
Explanation: ***Timolol eye drops*** - **Timolol** is a **beta-blocker** used to reduce intraocular pressure in **glaucoma** by decreasing aqueous humor production. - It has **no role in iridocyclitis management** as it does not address inflammation, pain, or pupillary abnormalities, which are the key therapeutic targets. - Timolol is simply not part of the treatment protocol for iridocyclitis. *Pilocarpine eye drops* - **Pilocarpine** is a **miotic** agent that constricts the pupil, but it is **contraindicated** in iridocyclitis (not just "not used"). - While not used therapeutically, it's important to distinguish that pilocarpine is actively harmful (increases inflammation and posterior synechiae risk), whereas timolol is simply not indicated. - In the context of this question asking what is "not used in treatment," timolol is the better answer as it's not part of the standard treatment protocol. *Atropine eye ointment* - **Atropine** is a **cycloplegic and mydriatic** agent that is a **cornerstone of iridocyclitis treatment**. - It dilates the pupil and paralyzes the ciliary muscle to prevent and break **posterior synechiae** and relieve pain from ciliary muscle spasm. - By immobilizing the iris and ciliary body, it reduces inflammation and discomfort. *Steroid eye drops* - **Steroid eye drops** (e.g., prednisolone acetate) are **essential for managing iridocyclitis** as they effectively reduce inflammation within the anterior chamber. - They suppress the immune response causing inflammation, thereby alleviating symptoms like redness, pain, and photophobia. - Topical corticosteroids are the mainstay of anti-inflammatory treatment in anterior uveitis.
Question 8: A mother reports that her daughter ingested a substance in an unknown dose. The girl presents with hypertension, tachycardia, mydriasis, and hyperthermia. What is the most likely substance?
- A. Heroin
- B. Morphine
- C. Cocaine (Correct Answer)
- D. Chlorpheniramine
- E. Organophosphate
Explanation: ***Cocaine*** - The presented symptoms of **hypertension, tachycardia, mydriasis, and hyperthermia** are characteristic of a **sympathomimetic toxidrome**, frequently caused by cocaine overdose. - Cocaine acts as a **norepinephrine-dopamine-serotonin reuptake inhibitor**, leading to excessive stimulation of the central and peripheral nervous systems. *Heroin* - Heroin is an **opioid**, and overdose generally presents with **respiratory depression, bradycardia, miosis (pinpoint pupils)**, and hypotension, which are contrary to the patient's symptoms. - Patients typically exhibit central nervous system **depression**, rather than the hyperactive state seen here. *Morphine* - Similar to heroin, morphine is an **opioid** and causes symptoms like **respiratory depression, bradycardia, miosis**, and hypotension. - These effects are the opposite of the **sympathomimetic** signs observed in the patient. *Chlorpheniramine* - Chlorpheniramine is an **antihistamine** with significant **anticholinergic effects**. An overdose might cause **mydriasis and tachycardia**, but not typically severe hypertension or hyperthermia as the primary features. - Other anticholinergic signs such as **dry mucous membranes, urinary retention, and altered mental status (delirium)** would also be expected. *Organophosphate* - Organophosphate poisoning causes a **cholinergic toxidrome** due to **acetylcholinesterase inhibition**, resulting in excessive cholinergic stimulation. - Classic presentation includes **SLUDGE syndrome** (Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis) along with **miosis (pinpoint pupils), bradycardia, bronchospasm**, and muscle fasciculations. - These findings are the **opposite** of the sympathomimetic signs seen in this patient.
Question 9: Primary objective of the use of atropine in anterior uveitis
- A. Rest to the ciliary muscle (Correct Answer)
- B. Helps in preventing posterior synechia formation
- C. Increase blood flow
- D. Increase supply of antibody
Explanation: ***Rest to the ciliary muscle*** - Atropine is a **cycloplegic** agent that paralyzes the **ciliary muscle**, thereby alleviating pain caused by spasms and inflammation in anterior uveitis. - This **cycloplegia** is the primary therapeutic goal, as it reduces **ciliary spasm** and the associated pain. *Helps in preventing posterior synechia formation (secondary effect)* - While atropine's **mydriatic** action (pupil dilation) helps prevent the formation of **posterior synechiae**, this is a beneficial secondary effect and not its primary objective in alleviating symptoms or pain. - The dilation breaks existing synechiae or prevents new ones from forming by moving the iris away from the lens capsule. *Increase blood flow* - Atropine's primary action is anticholinergic, leading to **cycloplegia** and **mydriasis**, not a direct increase in ocular blood flow. - Increased blood flow is not a targeted therapeutic effect of atropine in acute anterior uveitis. *Increase supply of antibody* - Atropine does not directly influence the immune system or increase the supply of antibodies to the inflamed eye. - Its mechanism of action is limited to blocking muscarinic acetylcholine receptors.
Question 10: 1% atropine is given in uveitis to:
- A. Cause miosis and prevent formation of posterior synechiae
- B. Cause mydriasis and prevent formation of anterior synechiae
- C. Cause mydriasis and prevent formation of posterior synechiae (Correct Answer)
- D. Reduce inflammation and relieve pain
Explanation: ***Cause mydriasis and prevent formation of posterior synechiae*** - **Atropine** is a **cycloplegic** and mydriatic agent used in uveitis to dilate the pupil, which helps to separate the iris from the lens. - This dilation is crucial in preventing the formation of **posterior synechiae** (adhesions between the iris and the anterior lens capsule), which can lead to complications such as pupil distortion, secondary glaucoma, and cataracts. *Cause miosis and prevent formation of posterior synechiae* - **Atropine** causes **mydriasis** (pupil dilation), not miosis (pupil constriction). - Miosis would increase the risk of posterior synechiae formation by bringing the iris and lens closer together. *Cause mydriasis and prevent formation of anterior synechiae* - **Anterior synechiae** are adhesions between the iris and the cornea, which are less commonly affected by atropine in uveitis compared to posterior synechiae. - While atropine causes mydriasis, its primary role in preventing synechiae formation in uveitis is directed at **posterior synechiae**. *Reduce inflammation and relieve pain* - While **atropine** can indirectly relieve pain by reducing **ciliary spasm** (a component of uveitic pain), its primary mechanism of action is not to reduce inflammation. - **Corticosteroids** are the main treatment for reducing inflammation in uveitis.
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