Glaucoma Practice Questions

Q: A 60-year-old woman presents with eye pain. Her intraocular pressure is 22 mm Hg in the right eye and 25 mm Hg in the left eye. What is the most likely cause of her eye pain?

Increased hydraulic resistance of the trabecular meshwork. **Explanation:** The patient presents with elevated intraocular pressure (IOP) (normal range: 10–21 mm Hg), which is the hallmark of glaucoma. In the vast majority of primary glaucoma cases, the elevation in IOP is not due to an overproduction of fluid, but rather a **failure in the drainage mechanism.** **Why Option C is Correct:** The primary site of resistance to aqueous outflow in the conventional pathway is the **juxtacanalicular trabecular meshwork** and Schlemm’s canal. In conditions like Primary Open Angle Glaucoma (POAG), pathological changes (such as deposition of extracellular matrix or loss of trabecular cells) lead to **increased hydraulic resistance**. This resistance prevents aqueous humor from exiting the eye at a normal rate, leading to a buildup of pressure. **Why Other Options are Incorrect:** * **Options A & B:** Decreased resistance or decreased production would lead to **hypotony** (low IOP), not the elevated levels seen in this patient. * **Option D:** While it seems logical that "more fluid equals more pressure," **increased production** of aqueous humor is almost never the primary cause of clinical glaucoma. The ciliary body production rate remains relatively constant; the pathology lies in the "clogged" drain (the meshwork). **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for IOP:** Goldmann Applanation Tonometry (GAT). * **Most common site of resistance:** Juxtacanalicular trabecular meshwork. * **Normal Aqueous Production:** ~2–2.5 µL/min. * **Drainage Pathways:** 90% via the Trabecular (conventional) pathway; 10% via the Uveoscleral (unconventional) pathway. * **Drug Link:** Prostaglandin analogs (Latanoprost) increase uveoscleral outflow, while Beta-blockers (Timolol) decrease aqueous production.

Q: Which of the following substances is found in higher concentration in aqueous humor compared to plasma?

Lactate. **Explanation:** The composition of aqueous humor is meticulously regulated by the ciliary body through diffusion, ultrafiltration, and active secretion. While aqueous humor is essentially an ultrafiltrate of plasma, its concentrations of specific solutes differ significantly due to the metabolic demands of the avascular lens and cornea. **Why Lactate is the Correct Answer:** Aqueous humor contains a **higher concentration of Lactate** (and Ascorbate) compared to plasma. This is primarily due to the **anaerobic glycolysis** occurring in the lens and the corneal epithelium. Since these structures are avascular, they metabolize glucose into lactate, which is then excreted into the aqueous humor, leading to a relative excess compared to systemic circulation. **Analysis of Incorrect Options:** * **Protein (A):** Aqueous humor is significantly **protein-poor** (approx. 0.02 g/dL vs. 7 g/dL in plasma). This is crucial for maintaining optical clarity and the Blood-Aqueous Barrier. * **Urea (B):** Urea levels are slightly **lower** in the aqueous humor compared to plasma. * **Glucose (C):** Glucose levels are roughly **20-30% lower** in the aqueous than in plasma because it is actively consumed by the lens and cornea for energy. **High-Yield NEET-PG Pearls:** * **Ascorbate (Vitamin C):** Found in concentrations **15–20 times higher** in aqueous than plasma; it acts as a potent antioxidant protecting against UV damage. * **Chloride & Bicarbonate:** These ions are also found in higher concentrations in the aqueous humor due to active transport by the ciliary epithelium. * **Specific Gravity:** Aqueous humor has a specific gravity of 1.002–1.004. * **pH:** Slightly more acidic than plasma (pH ~7.2).

Q: What is the drug of choice for primary open-angle glaucoma?

Prostaglandin analogues. **Explanation:** **Prostaglandin Analogues (PGAs)**, such as Latanoprost, Bimatoprost, and Travoprost, are the **first-line drug of choice** for Primary Open-Angle Glaucoma (POAG). Their primary mechanism of action is increasing the **uveoscleral outflow** of aqueous humor. They are preferred because of their superior efficacy in lowering Intraocular Pressure (IOP), long duration of action (allowing for **once-daily dosing**), and lack of systemic side effects compared to other classes. **Analysis of Options:** * **Beta Blockers (e.g., Timolol):** These were previously the first-line treatment. They work by decreasing aqueous production from the ciliary body. However, they are now second-line due to systemic contraindications like bronchial asthma, heart block, and bradycardia. * **Alpha Agonists (e.g., Brimonidine):** These provide a dual mechanism (decreasing production and increasing uveoscleral outflow) but are generally used as adjunctive therapy due to a high incidence of local allergic reactions (follicular conjunctivitis). * **Cholinergics (e.g., Pilocarpine):** These increase trabecular outflow by contracting the ciliary muscle. They are rarely used in POAG today due to side effects like miosis, brow ache, and risk of retinal detachment; they remain the drug of choice for Acute Angle Closure Glaucoma. **High-Yield Clinical Pearls for NEET-PG:** * **Side Effects of PGAs:** Increased eyelash growth (trichomegaly), iris hyperpigmentation (permanent), and cystoid macular edema (CME). * **Contraindication:** PGAs should be avoided in patients with active uveitis or a history of herpetic keratitis. * **Most Potent PGA:** Bimatoprost is often cited as having the greatest IOP-lowering effect.

Q: Miotics are used in the treatment of which condition?

Angle closure glaucoma. **Explanation:** **Miotics** (such as Pilocarpine) are primarily used in the management of **Angle Closure Glaucoma**. The underlying mechanism involves the contraction of the sphincter pupillae muscle, which causes miosis (pupillary constriction). This action pulls the peripheral iris away from the trabecular meshwork, physically opening the drainage angle and allowing the aqueous humor to reach the outflow channels. In acute attacks, pilocarpine also helps to thin the iris, making it easier for a Peripheral Iridotomy (PI) to be performed later. **Analysis of Incorrect Options:** * **Open Angle Glaucoma:** While miotics were historically used, they are no longer first-line treatments due to side effects (e.g., brow ache, accommodative spasm, and decreased night vision). Prostaglandin analogues and Beta-blockers are preferred. * **After Cataract (PCO):** This is a membrane opacity behind an IOL treated with YAG laser capsulotomy; miotics have no therapeutic role here. * **Posterior Uveitis:** Miotics are strictly **contraindicated** in uveitis. They promote the formation of posterior synechiae (adhesions between the iris and lens) and increase inflammation by breaking the blood-aqueous barrier. Mydriatics (like Atropine) are used instead to provide rest to the ciliary body and prevent synechiae. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Pilocarpine is the miotic of choice, but it is ineffective if Intraocular Pressure (IOP) is >40-50 mmHg because the iris sphincter becomes ischemic and non-responsive. * **Pre-Laser Use:** Miotics are used before YAG PI to stretch the iris, making it thinner and easier to penetrate. * **Side Effect:** A serious but rare side effect of miotics is **Retinal Detachment**, caused by the forward pull on the vitreous base during ciliary muscle contraction.

Q: Which drug is contraindicated in a patient with narrow-angle glaucoma?

Homatropine. **Explanation:** **Why Homatropine is the Correct Answer:** Homatropine is a **mydriatic-cycloplegic** drug (an anticholinergic). In patients with a pre-existing narrow anterior chamber angle, inducing mydriasis (dilation of the pupil) causes the peripheral iris tissue to bunch up and crowd the angle of the anterior chamber. This further obstructs the trabecular meshwork, blocking the outflow of aqueous humor. This can precipitate an **acute attack of Angle-Closure Glaucoma**, which is a sight-threatening emergency. Therefore, all strong mydriatics (Atropine, Homatropine, Cyclopentolate) are strictly contraindicated in narrow-angle glaucoma. **Analysis of Incorrect Options:** * **Acetazolamide (Option A):** A Carbonic Anhydrase Inhibitor that reduces aqueous production. It is actually a first-line treatment for managing acute angle-closure glaucoma. * **Timolol (Option B):** A non-selective Beta-blocker that decreases aqueous humor secretion. It is commonly used to lower intraocular pressure in various types of glaucoma. * **Pilocarpine (Option D):** A miotic (parasympathomimetic). It causes pupillary constriction, which pulls the iris away from the angle, opening the drainage pathway. It is the **drug of choice** for the initial management of acute angle-closure glaucoma. **High-Yield Clinical Pearls for NEET-PG:** * **Mydriatics** (e.g., Homatropine) are **contraindicated** in narrow-angle glaucoma but are used in inflammatory conditions like iridocyclitis to prevent synechiae. * **Miotics** (e.g., Pilocarpine) are **contraindicated** in inflammatory glaucoma (uveitic glaucoma) as they may increase the risk of posterior synechiae. * **Gold Standard Treatment** for Angle-Closure Glaucoma: Definitive treatment is **Peripheral Iridotomy** (usually via Nd:YAG laser).

Q: Which of the following is true about primary angle closure glaucoma?

All of the above.. Primary Angle Closure Glaucoma (PACG) is a condition where the peripheral iris obstructs the trabecular meshwork, leading to increased intraocular pressure. It is primarily a disease of "small eyes" with crowded anterior segments. **Explanation of Options:** * **Option A (Gender):** PACG is significantly more common in **females** (ratio approx. 3:1). This is attributed to the fact that women generally have shallower anterior chambers and shorter axial lengths compared to men. * **Option B (Anterior Chamber Depth):** A **shallow anterior chamber** (axial depth <2.5 mm) is the hallmark anatomical predisposition. This crowding increases the likelihood of pupillary block and subsequent iridocorneal contact. * **Option C (Corneal Diameter):** A **shorter corneal diameter** (microcornea) and a smaller eyeball (short axial length/hypermetropia) result in a disproportionately large lens relative to the small anterior segment, predisposing the eye to angle closure. Since all three anatomical and demographic factors are classic features of PACG, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Refractive Error:** PACG is associated with **Hypermetropia** (small eyes), whereas Primary Open Angle Glaucoma (POAG) is associated with Myopia. * **The Lens:** As age increases, the lens grows in thickness (phakomorphic component), further shallowing the anterior chamber. * **Provocative Factors:** Mydriasis (pupillary dilation) can trigger an acute attack; hence, drugs like atropine are contraindicated. * **Gold Standard Treatment:** **Laser Peripheral Iridotomy (LPI)** is the definitive management to bypass pupillary block.

Q: Which of the following is NOT a symptom of angle closure glaucoma?

Metamorphopsia. ### Explanation **Angle-Closure Glaucoma (ACG)** is a medical emergency characterized by a rapid rise in intraocular pressure (IOP) due to the mechanical obstruction of the trabecular meshwork by the peripheral iris. **Why Metamorphopsia is the Correct Answer:** **Metamorphopsia** (distortion of shapes/straight lines) is a hallmark symptom of **macular pathology**, such as Age-related Macular Degeneration (ARMD) or Central Serous Chorioretinopathy (CSCR). It occurs due to the displacement of photoreceptors in the retina. It is **not** a feature of glaucoma, which primarily affects the optic nerve head and peripheral visual fields. **Analysis of Other Options:** * **Blurring of Vision:** In ACG, the sudden rise in IOP causes the corneal endothelium to fail, leading to **corneal edema**. This edema disrupts light transmission, resulting in hazy or blurred vision. * **Coloured Halos:** This is a classic symptom of ACG. Edematous corneal stroma acts as a diffraction grating, splitting white light into its spectral components (rainbow-like halos around lights). * **Headache:** The extreme elevation of IOP (often >50 mmHg) stimulates the ophthalmic division of the trigeminal nerve, causing severe ocular pain, brow ache, and frontal headache, often accompanied by nausea and vomiting. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of ACG:** Shallow anterior chamber, fixed mid-dilated pupil, and "stony hard" eye on palpation. * **Differential for Halos:** Apart from ACG, halos are seen in **immature cataracts** (due to protein water droplets) and **mucopurulent conjunctivitis** (due to mucus flakes; these disappear on blinking, whereas glaucoma halos do not). * **Immediate Management:** Systemic Acetazolamide and topical Pilocarpine (once IOP drops below 40 mmHg). The definitive treatment is **Laser Peripheral Iridotomy (LPI)**.

Q: An elderly man presents with a painful red eye. On examination, the pupil is noted to be dilated and fixed. What is the next line of investigation?

Tonometry. **Explanation:** The clinical presentation of a **painful red eye** associated with a **dilated, fixed, vertically oval pupil** is a classic hallmark of **Acute Angle-Closure Glaucoma (AACG)**. In this emergency, the sudden rise in intraocular pressure (IOP) causes iris ischemia, leading to pupillary paralysis. 1. **Why Tonometry is the correct answer:** The immediate priority in a suspected case of AACG is to confirm the diagnosis by measuring the intraocular pressure. **Tonometry** (specifically Applanation Tonometry) is the definitive investigation to document the elevated IOP, which often exceeds 40–70 mmHg in these patients. Prompt diagnosis is vital to initiate pressure-lowering treatment and prevent permanent optic nerve damage. 2. **Why other options are incorrect:** * **Visual Evoked Potential (VEP):** This is used to assess the functional integrity of the visual pathway (e.g., optic neuritis) and has no role in the acute management of a red eye. * **Retinal Angiogram (FFA):** This is used to evaluate vascular pathologies like diabetic retinopathy or macular degeneration; it is not indicated in acute glaucoma. * **Slit Lamp Examination:** While useful for seeing a shallow anterior chamber or corneal edema, it is a diagnostic tool rather than the specific investigation to confirm the *pressure* elevation. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of AACG:** Sudden ocular pain, "halos" around lights, and a stony-hard eye on palpation. * **Gold Standard for Diagnosis:** Gonioscopy (to visualize the closed angle), but **Tonometry** is the immediate next step for pressure assessment. * **Drug of Choice (Immediate):** IV Acetazolamide and topical pilocarpine (once IOP drops below 40 mmHg). * **Definitive Treatment:** Peripheral Iridotomy (Laser or Surgical).

Q: What is the normal diurnal variation of intraocular pressure?

3-6 mm of Hg. ### Explanation **1. Understanding the Correct Answer (C: 3-6 mm Hg)** Intraocular pressure (IOP) is not static; it fluctuates throughout a 24-hour period due to changes in aqueous humor production and drainage, as well as variations in circulating cortisol and melatonin levels. In a healthy, non-glaucomatous eye, this **diurnal variation** typically ranges between **3 to 6 mm Hg**. IOP is generally highest in the early morning hours (phasic variation) and lowest in the evening. **2. Analysis of Incorrect Options** * **Options A & B (0-3 mm Hg):** These values are too narrow. While some individuals may show very stable IOP, the physiological norm accounts for a wider range of fluctuation due to postural changes and circadian rhythms. * **Option D (6-8 mm Hg):** This range is considered suspicious. A diurnal variation exceeding **8 mm Hg** is highly suggestive of **Glaucoma**, even if the absolute IOP readings fall within the "normal" range (10-21 mm Hg) during office hours. **3. Clinical Pearls for NEET-PG** * **Gold Standard for Measurement:** The **Goldmann Applanation Tonometer (GAT)** is the gold standard for measuring IOP. * **Glaucoma Diagnosis:** In glaucomatous eyes, the diurnal fluctuation is exaggerated (often >10 mm Hg). This is why a single "normal" IOP reading in the afternoon does not rule out glaucoma. * **Diurnal Variation Recording:** To accurately capture these peaks, a **Diurnal Variation Chart (DVC)** is maintained, measuring IOP every 3-4 hours over a 24-hour period. * **Postural Influence:** IOP is typically higher in the **supine position** compared to the sitting position due to increased episcleral venous pressure.

Question 1

A 60-year-old woman presents with eye pain. Her intraocular pressure is 22 mm Hg in the right eye and 25 mm Hg in the left eye. What is the most likely cause of her eye pain?

Accepted Answer

Increased hydraulic resistance of the trabecular meshwork

Answer

Decreased hydraulic resistance of the trabecular meshwork

Answer

Decreased production of aqueous humor

Answer

Increased production of aqueous humor

Question 2

Which of the following substances is found in higher concentration in aqueous humor compared to plasma?

Accepted Answer

Lactate

Answer

Protein

Answer

Urea

Answer

Glucose

Question 3

What is the drug of choice for primary open-angle glaucoma?

Accepted Answer

Prostaglandin analogues

Answer

Beta blockers

Answer

Alpha agonists

Answer

Cholinergics

Question 4

Miotics are used in the treatment of which condition?

Accepted Answer

Angle closure glaucoma

Answer

Open angle glaucoma

Answer

After cataract

Answer

Posterior uveitis

Question 5

Which drug is contraindicated in a patient with narrow-angle glaucoma?

Accepted Answer

Homatropine

Answer

Acetazolamide

Answer

Timolol

Answer

Pilocarpine

Question 6

Which of the following is true about primary angle closure glaucoma?

Accepted Answer

All of the above.

Answer

It is more common in females.

Answer

It is characterized by a shallow anterior chamber.

Answer

A shorter corneal diameter is a predisposing factor.

Question 7

Which of the following is NOT a symptom of angle closure glaucoma?

Accepted Answer

Metamorphopsia

Answer

Blurring of vision

Answer

Coloured halos

Answer

Headache

Question 8

A patient complains of seeing colored halos around lights in the evening and blurring of vision for the past few days, with normal intraocular pressure (IOP). What is the most likely diagnosis?

Accepted Answer

Prodromal phase of acute angle closure glaucoma

Answer

Acute angle closure glaucoma

Answer

Chronic glaucoma

Answer

Epidemic dropsy

Question 9

An elderly man presents with a painful red eye. On examination, the pupil is noted to be dilated and fixed. What is the next line of investigation?

Accepted Answer

Tonometry

Answer

Visual evoked potential

Answer

Retinal angiogram

Answer

Slit lamp examination

Question 10

What is the normal diurnal variation of intraocular pressure?

Accepted Answer

3-6 mm of Hg

Answer

0-2 mm of Hg

Answer

2-3 mm of Hg

Answer

6-8 mm of Hg

Glaucoma — MCQs

Glaucoma — MCQs

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