Glaucoma Practice Questions

Q: How do hyperosmolar agents act in glaucoma?

Decreasing vitreous volume. ### **Explanation** Hyperosmolar agents (such as **Mannitol** and **Glycerol**) act by creating an osmotic gradient between the blood and the intraocular fluids. **1. Why "Decreasing vitreous volume" is correct:** The primary mechanism of action for these agents is the **osmotic dehydration of the vitreous**. Because the blood-ocular barrier is relatively impermeable to these large molecules, they remain in the intravascular compartment, drawing water out of the vitreous body into the bloodstream. This reduction in vitreous volume causes the lens-iris diaphragm to shift backward, deepening the anterior chamber and rapidly lowering intraocular pressure (IOP). **2. Why the other options are incorrect:** * **A & D (Increasing aqueous/uveoscleral outflow):** These are the mechanisms of Prostaglandin analogues (uveoscleral) and Miotics/Trabeculoplasty (trabecular outflow). Hyperosmolar agents do not affect the drainage pathways. * **C (Decreasing aqueous production):** This is the mechanism of Carbonic Anhydrase Inhibitors (Acetazolamide) and Beta-blockers (Timolol). **3. NEET-PG High-Yield Pearls:** * **Mannitol (IV):** The most common agent used in acute emergencies (e.g., Acute Angle Closure Glaucoma). It is not metabolized and is excreted by the kidneys. * **Glycerol (Oral):** Effective but must be used cautiously in diabetics as it is metabolized into glucose, potentially causing hyperglycemia. * **Contraindications:** Congestive Heart Failure (CHF) and pulmonary edema, as these agents cause rapid expansion of extracellular fluid volume. * **Clinical Use:** Primarily used for rapid "de-bulking" of the eye before intraocular surgery or in acute hypertensive phases of glaucoma.

Q: Which of the following is NOT a cause of a shallow anterior chamber?

Pathological myopia. **Explanation:** The depth of the anterior chamber (AC) is determined by the anatomical dimensions of the eyeball and the pressure relationship between the posterior and anterior chambers. **Why Pathological Myopia is the Correct Answer:** In **Pathological Myopia**, the eyeball is abnormally long (increased axial length). This elongation typically results in a **deep anterior chamber**, a wide iridocorneal angle, and a large crystalline lens. Because the question asks for which condition does *NOT* cause a shallow AC, pathological myopia is the correct choice. **Analysis of Incorrect Options:** * **Hypermetropia with small axial length:** Hypermetropic eyes are anatomically smaller. A short axial length combined with a relatively large lens crowds the anterior segment, leading to a shallow AC and predisposing the patient to primary angle-closure glaucoma. * **Pupil block due to vitreous bulge (Aphakic Glaucoma):** After intracapsular cataract extraction (ICCE), the vitreous face can move forward and block the pupil. This prevents aqueous humor from reaching the AC, causing a pressure buildup in the posterior chamber that pushes the iris forward, shallowing the AC. * **Iris bombe:** This occurs due to 360-degree posterior synechiae (seclusio pupillae). The trapped aqueous in the posterior chamber causes the peripheral iris to bulge forward (bombe), significantly shallowing the AC. **NEET-PG High-Yield Pearls:** * **Normal AC Depth:** Approximately 2.5 to 3.0 mm. * **Shallow AC Causes:** Hypermetropia, Intumescent cataract (phacomorphic), Malignant glaucoma (ciliary block), and Plateau iris syndrome. * **Deep AC Causes:** Myopia, Aphakia, Keratoglobus, and Buphthalmos (Congenital Glaucoma). * **Clinical Sign:** A shallow AC is a hallmark of **Angle-Closure Glaucoma**, while a deep AC is typically seen in **Open-Angle Glaucoma**.

Q: Peripheral anterior synechiae after an attack of acute congestive glaucoma occur earliest in which location?

Superior part. In **Acute Congestive Glaucoma** (Angle-Closure Glaucoma), Peripheral Anterior Synechiae (PAS) are permanent adhesions between the iris root and the trabecular meshwork. These form due to prolonged contact and subsequent inflammation during an acute attack. **Why the Superior Part is Correct:** The **superior part** of the iridocorneal angle is anatomically the **narrowest** part of the angle in the normal eye. Because the superior angle is already more shallow than other quadrants, it is the first area where the iris makes contact with the cornea/trabecular meshwork during an attack. Consequently, inflammatory exudates organize here first, leading to the earliest formation of PAS. **Analysis of Incorrect Options:** * **A, C, and D (Inferior, Nasal, and Temporal parts):** These quadrants are anatomically **wider** than the superior quadrant. Gravitational factors and the natural shape of the anterior chamber ensure that the inferior angle is typically the deepest. Therefore, these areas are involved later in the disease process as the angle closure progresses circumferentially. **High-Yield Clinical Pearls for NEET-PG:** * **Gonioscopy:** This is the gold standard for identifying PAS. PAS are distinguished from "iris processes" by their broad base and ability to obscure the trabecular meshwork. * **Sequence of Angle Width:** Inferior > Temporal > Nasal > Superior (The superior angle is the narrowest). * **Management:** Laser Peripheral Iridotomy (LPI) is the definitive treatment to bypass pupillary block, but it cannot reverse established PAS. * **Van Herick Technique:** A slit-lamp method to grade the angle; it is most commonly performed at the temporal limbus for ease, but the superior angle remains the most vulnerable.

Q: What is the initial treatment of malignant glaucoma?

Atropine. **Malignant Glaucoma (Ciliary Block Glaucoma)** is a rare but serious condition characterized by a shallow anterior chamber and elevated intraocular pressure (IOP), typically occurring after intraocular surgery in patients with narrow angles. ### **Why Atropine is the Correct Answer** The primary pathophysiology involves a **posterior diversion of aqueous humor** into the vitreous cavity, which pushes the lens-iris diaphragm forward. **Atropine (1% drops or ointment)** is the drug of choice because: 1. **Cycloplegia:** It relaxes the ciliary muscle, which tightens the suspensory ligaments (zonules). This pulls the lens backward into its normal anatomical position. 2. **Stabilization:** It helps reform the anterior chamber and breaks the "ciliary block" cycle. ### **Why Other Options are Incorrect** * **B. Topical Pilocarpine:** This is **contraindicated**. Pilocarpine causes miosis and ciliary muscle contraction, which moves the lens-iris diaphragm further forward, worsening the pupillary block and the condition. * **C. Intravenous Mannitol:** While hyperosmotics are used to dehydrate the vitreous and lower IOP, they are **adjunctive** treatments. Atropine remains the definitive initial medical step to reverse the underlying mechanism. * **D. Vitreous Aspiration:** This is a surgical intervention (Pars Plana Vitrectomy) reserved for cases that are refractory to medical management. ### **NEET-PG High-Yield Pearls** * **Classic Presentation:** Shallow anterior chamber (both central and peripheral) + High IOP + History of recent surgery (e.g., iridectomy or cataract surgery). * **Medical Management Triad:** Mydriatic-cycloplegics (Atropine), Carbonic anhydrase inhibitors (Acetazolamide), and Hyperosmotics (Mannitol). * **Definitive Surgical Treatment:** Nd:YAG laser hyaloidotomy or Pars Plana Vitrectomy (PPV) to create a communication between the vitreous and the anterior chamber.

Q: Which one of the following is NOT used in the management of glaucoma?

Donepezil. **Explanation:** The management of glaucoma focuses on lowering intraocular pressure (IOP) by either decreasing aqueous humor production or increasing its outflow. **Why Donepezil is the Correct Answer:** **Donepezil** is a centrally acting reversible acetylcholinesterase inhibitor used primarily in the treatment of **Alzheimer’s disease**. While it increases acetylcholine levels in the brain to improve cognitive function, it has no clinical role in the management of glaucoma. In fact, because of its cholinergic effects, it can theoretically cause miosis or worsen certain types of glaucoma, though it is not used therapeutically for eye conditions. **Analysis of Incorrect Options:** * **Timolol (Option A):** A non-selective **beta-blocker** and traditionally the first-line treatment for glaucoma. It works by decreasing aqueous humor production from the ciliary body. * **Physostigmine (Option B):** A **parasympathomimetic (miotic)** agent. It is an acetylcholinesterase inhibitor that increases acetylcholine at the iris sphincter, causing miosis and opening the trabecular meshwork to increase aqueous outflow. * **Dipivefrine (Option C):** A **prodrug of epinephrine**. It is more lipophilic and penetrates the cornea better than epinephrine. It lowers IOP by increasing uveoscleral outflow and decreasing aqueous production. **NEET-PG High-Yield Pearls:** * **Drug of Choice (DOC):** Prostaglandin analogues (e.g., Latanoprost) are currently the first-line treatment for Primary Open Angle Glaucoma (POAG) due to superior efficacy and once-daily dosing. * **Mechanism of Action (MOA) Tip:** Beta-blockers and Carbonic Anhydrase Inhibitors (Acetazolamide) **decrease production**, while Miotics and Prostaglandins **increase outflow**. * **Contraindication:** Avoid Beta-blockers (Timolol) in patients with asthma or heart block.

Q: Which of the following is not a disc sign in glaucoma?

Disc edema. In glaucoma, the primary pathological process is **progressive optic neuropathy** characterized by the death of retinal ganglion cells and loss of the neuroretinal rim. This leads to **pathological cupping**, not swelling. **Why Disc Edema is the Correct Answer:** Disc edema (swelling) is a sign of axonal stasis and increased volume of the optic nerve head. It is typically seen in conditions like papilledema (raised intracranial pressure), optic neuritis, or ischemic optic neuropathy. In contrast, glaucoma is a "hollowing out" process. While rare "splinter hemorrhages" (Drance hemorrhages) occur in glaucoma, the disc itself remains pale and excavated, never edematous. **Explanation of Incorrect Options (Glaucomatous Signs):** * **Bayonetting Sign:** This occurs when a vessel climbing out of the deep cup makes a sharp, 90-degree turn at the disc margin, appearing broken or shifted. * **Nasalization of Vessels:** As the cup expands temporally, the central retinal vessels are pushed toward the nasal side of the optic disc. * **Large Cup:** An increased Cup-Disc Ratio (CDR) >0.5 or asymmetry between eyes >0.2 is a hallmark of glaucomatous damage. **High-Yield Clinical Pearls for NEET-PG:** * **ISNT Rule:** In a normal disc, the neuroretinal rim thickness follows the order Inferior > Superior > Nasal > Temporal. Glaucoma often causes **notching**, usually starting at the inferior or superior poles, violating this rule. * **Laminar Dot Sign:** Exposure of the fenestrations of the lamina cribrosa due to deep cupping. * **Baring of Circumlinear Vessels:** A space develops between the vessel and the disc rim as the rim recedes. * **Alpha and Beta Zones:** Peripapillary atrophy; the **Beta zone** (adjacent to the disc) is more specific for glaucoma.

Q: Latanoprost is used in the treatment of which condition?

Glaucoma. **Explanation:** **Latanoprost** is a synthetic **Prostaglandin F2-alpha (PGF2α) analogue**. It is the first-line medical therapy for **Primary Open-Angle Glaucoma (POAG)** and Ocular Hypertension. **Why Glaucoma is correct:** Latanoprost works by increasing the **uveoscleral outflow** of aqueous humor (the unconventional pathway). By facilitating the drainage of fluid through the ciliary muscle into the suprachoroidal space, it effectively lowers Intraocular Pressure (IOP). It is preferred due to its once-daily dosing and superior efficacy compared to older drugs like Timolol. **Analysis of Incorrect Options:** * **A. Induction of labor:** While other prostaglandins like Dinoprostone (PGE2) and Misoprostol (PGE1) are used for cervical ripening and induction, Latanoprost is specifically formulated for ophthalmic use and has no role in obstetrics. * **B. Refraction:** Drugs used in refraction are cycloplegics (e.g., Atropine, Cyclopentolate) which paralyze the ciliary muscle to reveal the true refractive error. Latanoprost does not affect accommodation or pupil size significantly. * **C. Iridocyclitis:** This is an inflammatory condition (anterior uveitis). Treatment involves topical steroids and cycloplegics (to prevent synechiae). Prostaglandin analogues are actually **contraindicated** in active iridocyclitis as they are pro-inflammatory mediators. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Increases uveoscleral outflow (High yield). * **Side Effects:** Increased pigmentation of the iris (heterochromia), **hypertrichosis** (increased eyelash growth/thickness), and cystoid macular edema (CME). * **Storage:** Unopened bottles should be stored in a refrigerator (2-8°C). * **Other PGF2α analogues:** Bimatoprost, Travoprost, Tafluprost.

Q: Which of the following instruments is used as a self-tonometer?

Rebound tonometer. **Explanation:** The **Rebound Tonometer** (e.g., Icare) is the correct answer because it is designed for ease of use without the need for topical anesthesia or a slit lamp. It works on the principle of **induction-deceleration**: a tiny, disposable motorized probe bounces off the cornea, and the device measures the deceleration of the probe to calculate Intraocular Pressure (IOP). Because it is portable, requires no drops, and is minimally invasive, it is the primary instrument used for **home monitoring (self-tonometry)** and in pediatric populations. **Analysis of Incorrect Options:** * **Diaton Palpebral Tonometer:** This measures IOP through the **eyelid** (transpalpebral). While it doesn't require anesthesia, it is technically difficult to self-administer accurately and is less reliable than rebound tonometry. * **Perkins Tonometer:** This is a **handheld version of the Goldmann Applanation Tonometer (GAT)**. While portable, it requires topical anesthesia (Proparacaine) and Fluorescein dye, making it unsuitable for self-use. It is ideal for bedridden or anesthetized patients. * **Dynamic Contour Tonometer (Pascal):** This uses a piezoelectric sensor to measure IOP and is unique because it is **independent of Central Corneal Thickness (CCT)**. However, it is a bulky, slit-lamp mounted device that cannot be used by a patient on themselves. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Goldmann Applanation Tonometry (GAT) remains the clinical gold standard. * **Imbert-Fick Law:** The principle behind applanation tonometry ($P = F/A$). * **Schiotz Tonometer:** An older, indentation tonometer that uses a conversion table; it is prone to errors based on **scleral rigidity**. * **Non-Contact Tonometer (Air-puff):** Commonly used for screening; it uses a puff of air to flatten the cornea.

Question 1

How do hyperosmolar agents act in glaucoma?

Accepted Answer

Decreasing vitreous volume

Answer

Increasing aqueous outflow

Answer

Decreasing aqueous production

Answer

Facilitating uveoscleral outflow

Question 2

Which test is used to differentiate halos due to angle closure glaucoma and immature cataract?

Accepted Answer

Differentiating halos due to angle closure glaucoma and immature cataract

Answer

Differentiating open angle from angle closure glaucoma

Answer

Classifying glaucomatous optic atrophy

Answer

Differentiating granulomatous and non-granulomatous uveitis

Question 3

Which of the following is NOT a cause of a shallow anterior chamber?

Accepted Answer

Pathological myopia

Answer

Hypermetropia with a small axial length

Answer

Pupil block due to vitreous bulge after intracapsular cataract extraction

Answer

Iris bombe

Question 4

Peripheral anterior synechiae after an attack of acute congestive glaucoma occur earliest in which location?

Accepted Answer

Superior part

Answer

Inferior part

Answer

Inferior and nasal part

Answer

Inferior and temporal part

Question 5

What is the initial treatment of malignant glaucoma?

Accepted Answer

Atropine

Answer

Topical pilocarpine

Answer

Intravenous mannitol

Answer

Vitreous aspiration

Question 6

Which of the following statements regarding pigmentary glaucoma is false?

Accepted Answer

It is an angle closure glaucoma caused by the accumulation of pigments.

Answer

It is a type of secondary open-angle glaucoma.

Answer

Slit-lamp microscopy shows Krukenberg spindles of pigment on the corneal endothelium.

Answer

Gonioscopy may show a Sampaolesi line.

Question 7

Which one of the following is NOT used in the management of glaucoma?

Accepted Answer

Donepezil

Answer

Timolol

Answer

Physostigmine

Answer

Dipivefrine

Question 8

Which of the following is not a disc sign in glaucoma?

Accepted Answer

Disc edema

Answer

Bayonetting

Answer

Nasalization of vessels

Answer

Large cup

Question 9

Latanoprost is used in the treatment of which condition?

Accepted Answer

Glaucoma

Answer

Induction of labor

Answer

Refraction

Answer

Iridocyclitis

Question 10

Which of the following instruments is used as a self-tonometer?

Accepted Answer

Rebound tonometer

Answer

Diaton palpebral tonometer

Answer

Perkins tonometer

Answer

Dynamic contour tonometer

Glaucoma — MCQs

Glaucoma — MCQs

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