Glaucoma Practice Questions

Q: What is the earliest visual field change in open-angle glaucoma?

Paracentral scotoma. In Primary Open-Angle Glaucoma (POAG), visual field defects follow a specific chronological sequence based on the damage to the retinal nerve fiber layer (RNFL). ### **Why Paracentral Scotoma is Correct** The **earliest** clinically detectable visual field change in glaucoma is a **paracentral scotoma**. These are small, isolated islands of vision loss typically located between 10° and 20° from the fixation point. They occur due to early damage to the papillomacular bundle or adjacent arcuate fibers. While generalized depression of the field or increased fluctuation in responses may occur first, the paracentral scotoma is the first definitive localized defect. ### **Analysis of Incorrect Options** * **Siedel’s Scotoma:** This occurs when a paracentral scotoma enlarges and reaches the blind spot. It is a **progression** of the initial defect, not the earliest sign. * **Arcuate (Bjerrum) Scotoma:** This is a late-stage defect formed by the coalescence of paracentral and Siedel’s scotomas, creating a comma-shaped defect extending from the blind spot around the fixation point. * **Ring Scotoma:** This is an **advanced** stage defect where superior and inferior arcuate scotomas meet. It is also classically associated with Retinitis Pigmentosa. ### **High-Yield Clinical Pearls for NEET-PG** * **Sequence of Defects:** Paracentral scotoma → Siedel’s scotoma → Arcuate/Bjerrum scotoma → Ring scotoma → Tubular vision. * **Roenne’s Nasal Step:** A defect that respects the horizontal midline; it is a very common early sign but often appears alongside or slightly after paracentral scotomas. * **Bjerrum’s Area:** The arcuate area between 10°–20° from fixation where most glaucomatous defects originate. * **Gold Standard:** Automated Perimetry (specifically the Humphrey Field Analyzer) is the standard for detecting these changes.

Q: Tonography helps determine which of the following?

The facility of aqueous humor outflow.. **Explanation:** **Tonography** is a non-invasive diagnostic procedure used to measure the **facility of aqueous humor outflow** (represented by the coefficient ‘C’). It is based on the principle that applying a constant weight to the eye (usually via a Schiotz tonometer) will artificially raise intraocular pressure (IOP), thereby forcing aqueous humor out of the eye. By measuring the rate at which the IOP falls over a specific period (usually 4 minutes), clinicians can calculate how easily fluid leaves the eye through the trabecular meshwork. * **Option A is incorrect:** The rate of aqueous humor formation is typically measured using **fluorophotometry**, not tonography. * **Option C is incorrect:** Measuring IOP at different times of the day refers to **Diurnal Variation Testing** (Phasic Tension Curve), which is used to detect the peak pressure spikes in glaucoma patients. **High-Yield Clinical Pearls for NEET-PG:** * **Grant’s Equation:** The mathematical basis for tonography is $C = \frac{\Delta V}{t \times (\text{P}_{av} - \text{P}_e)}$, where 'C' is the facility of outflow. * **Normal Value:** The normal value for the facility of outflow (C) is approximately **0.22 to 0.28 $\mu$L/min/mmHg**. A value below **0.18** is considered suspicious for glaucoma. * **Becker’s Ratio:** Calculated as **Po/C** (Initial IOP / Facility of outflow). A ratio greater than **100** is highly suggestive of Open Angle Glaucoma. * **Current Status:** While historically significant, tonography is rarely used in modern clinical practice due to its technical difficulty and the advent of more reliable imaging like OCT.

Q: Neovascular glaucoma is not seen in which of the following conditions?

Juvenile Rheumatoid Arthritis (JRA). **Explanation:** Neovascular Glaucoma (NVG) is a secondary glaucoma caused by the formation of new vessels (neovascularization) on the iris (rubeosis iridis) and in the iridocorneal angle. The fundamental trigger for NVG is **retinal ischemia**, which leads to the release of Vascular Endothelial Growth Factor (VEGF). **Why JRA is the correct answer:** Juvenile Rheumatoid Arthritis (JRA) is typically associated with **chronic non-granulomatous anterior uveitis**. The primary mechanism of glaucoma in JRA is inflammatory, involving trabeculitis or the formation of peripheral anterior synechiae (PAS) due to inflammatory debris. It does **not** cause significant retinal ischemia; therefore, it does not lead to neovascularization. **Analysis of incorrect options:** * **CRVO:** This is the most common cause of NVG (specifically the ischemic type). It is often referred to as "100-day glaucoma" because NVG typically develops 3 months after the occlusion. * **CRAO:** While less common than in CRVO, about 5–10% of CRAO cases develop NVG due to the resulting inner retinal ischemia. * **Eales' Disease:** This is an idiopathic peripheral perivasculitis that causes severe peripheral retinal ischemia and vitreous hemorrhage, frequently leading to neovascularization of the disc, retina, and iris. **Clinical Pearls for NEET-PG:** * **Top 3 causes of NVG:** Diabetic Retinopathy (most common overall), Ischemic CRVO, and Carotid Artery Occlusive Disease. * **Management:** The priority is treating the underlying ischemia via **Pan-retinal Photocoagulation (PRP)** and anti-VEGF injections. * **JRA Triad:** Band-shaped keratopathy, chronic iridocyclitis, and complicated cataract.

Q: Triple surgery in glaucoma includes all of the following except?

Insertion of drainage device. **Explanation:** The term **"Triple Surgery"** in ophthalmology refers to a specific combined procedure designed to address both cataract and glaucoma in a single surgical sitting. The three components of this procedure are: 1. **Cataract Extraction:** This can be via Extra Capsular Cataract Extraction (ECCE), Small Incision Cataract Surgery (SICS), or Phacoemulsification. 2. **PCIOL Implantation:** Placement of a Posterior Chamber Intraocular Lens. 3. **Filtering Surgery:** Specifically, a **Trabeculectomy** (with or without antimetabolites like Mitomycin-C). **Why Option C is the correct answer:** A **Glaucoma Drainage Device (GDD)** or valve (e.g., Ahmed Glaucoma Valve) is used in refractory glaucomas where trabeculectomy has failed or is likely to fail (e.g., neovascular glaucoma). While a GDD can be combined with cataract surgery, it is **not** part of the classic definition of "Triple Surgery." **Analysis of Incorrect Options:** * **Option A (Trabeculectomy):** This is the standard "filtering" component of the triple procedure to lower intraocular pressure. * **Option B & D (PCIOL & ECCE):** These represent the cataract management portion of the procedure. Modern triple surgery usually utilizes Phacoemulsification, but ECCE remains a valid component in the classic definition. **High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Triple surgery is indicated in patients with significant cataract and advanced glaucoma where a single-stage procedure is preferred to avoid two separate surgeries. * **Advantage:** It prevents the post-operative IOP spikes often seen after standalone cataract surgery in glaucoma patients. * **Site:** It can be performed through a single incision (one-site) or two separate incisions (two-site). Two-site surgery is often preferred as it allows for better control of the bleb and less inflammation.

Q: Which of the following conditions is the drug of choice for a topical beta blocker?

Open angle glaucoma. **Explanation:** **Topical Beta Blockers (e.g., Timolol, Betaxolol)** are traditionally considered the first-line or primary medical therapy for **Open-Angle Glaucoma (OAG)** and Ocular Hypertension. Their primary mechanism of action is the **reduction of aqueous humor production** by inhibiting beta-receptors in the ciliary epithelium. * **Why Option B is Correct:** In Open-Angle Glaucoma, the goal is to lower intraocular pressure (IOP) to prevent optic nerve damage. Beta-blockers are highly effective, have a convenient twice-daily dosing schedule, and do not affect pupil size or accommodation, making them ideal for chronic management of OAG. * **Why Options A, C, and D are Incorrect:** * **Angle Closure Glaucoma:** The definitive treatment is peripheral iridotomy. While beta-blockers can help lower IOP, they are not the "drug of choice" for the underlying anatomical block. * **Hypopyon Corneal Ulcer:** This is an infectious/inflammatory condition requiring intensive topical antibiotics (e.g., fortified cephalosporins or fluoroquinolones) and cycloplegics. Beta-blockers have no role in treating the infection. * **Acute Granulomatous Uveitis:** The mainstay of treatment is topical steroids to control inflammation and cycloplegics (like Atropine) to prevent synechiae. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Decreases aqueous secretion (not increasing outflow). * **Contraindications:** Avoid in patients with **Bronchial Asthma**, COPD, or second/third-degree heart block due to systemic absorption via the nasolacrimal duct. * **Drug of Choice:** While Prostaglandin analogues (PGAs) are now often preferred for potency, Beta-blockers remain a classic "drug of choice" in exam questions for OAG. * **Betaxolol:** A cardioselective (Beta-1) blocker; it is safer for the lungs but less effective at lowering IOP than Timolol.

Q: Pilocarpine reduces intraocular pressure in persons with closed-angle glaucoma by:

Increasing aqueous humor outflow. **Explanation:** Pilocarpine is a direct-acting parasympathomimetic (miotic) agent. In **Primary Angle-Closure Glaucoma (PACG)**, the fundamental pathology is the mechanical obstruction of the trabecular meshwork by the peripheral iris. **Why Option C is correct:** Pilocarpine acts on the **muscarinic (M3) receptors** of the **iris sphincter muscle**, causing pupillary constriction (miosis). This contraction pulls the peripheral iris away from the trabecular meshwork, effectively "opening" the angle. By clearing this mechanical blockage, the aqueous humor can once again access the drainage channels, thereby **increasing aqueous humor outflow** and rapidly reducing intraocular pressure (IOP). **Why other options are incorrect:** * **Option A:** Aqueous secretion is reduced by Beta-blockers (Timolol), Alpha-2 agonists (Brimonidine), and Carbonic anhydrase inhibitors (Acetazolamide), not pilocarpine. * **Option B:** While pilocarpine *does* constrict the iris sphincter, this is the **mechanism**, not the physiological **result** that lowers IOP. The question asks how it reduces pressure; it does so by increasing outflow via miosis. * **Option D:** Pilocarpine actually causes **contraction** of the ciliary muscle (not relaxation). In open-angle glaucoma, this contraction pulls the scleral spur and opens the trabecular meshwork spaces. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Pilocarpine is the drug of choice for the immediate medical management of acute angle-closure glaucoma (usually 2% concentration). * **Paradoxical Effect:** It should not be used if the IOP is very high (>40-50 mmHg) because the iris sphincter becomes ischemic and unresponsive to the drug. * **Side Effects:** Accommodative spasm (induced myopia), brow ache, and increased risk of retinal detachment. * **Contraindication:** It is contraindicated in **Uveitic Glaucoma** as it may promote the formation of posterior synechiae.

Q: Based on the perimetry result print-out, what is the most likely diagnosis?

Open angle glaucoma. ***Open angle glaucoma*** - Characteristic **arcuate scotoma** and **nasal step** pattern on perimetry, beginning with **paracentral scotomas** that respect the horizontal meridian. - Progressive **peripheral visual field loss** that spares central vision until late stages, consistent with **glaucomatous optic neuropathy**. *Retinitis pigmentosa* - Presents with **ring-shaped scotomas** or **concentric peripheral field loss** starting from the periphery and progressing inward. - Associated with **night blindness** and **tunnel vision**, showing a different perimetric pattern than glaucomatous defects. *Pituitary adenoma* - Causes **bitemporal hemianopia** due to compression of the **optic chiasm**, affecting temporal fields of both eyes. - Field defects are **symmetric** and **homonymous**, respecting the vertical meridian rather than horizontal. *Temporal lobe infarct* - Results in **homonymous superior quadrantanopia** ("pie in the sky" defect) affecting the same quadrant in both eyes. - Visual field loss is **congruous** and involves the **contralateral visual field**, not the characteristic glaucomatous pattern.

Q: Which of the following is true about intraocular pressure?

It increases with advancing age.. **Explanation:** **Correct Option: D (It increases with advancing age)** Intraocular pressure (IOP) tends to increase with age due to structural and functional changes in the trabecular meshwork. With advancing age, there is a reduction in the number of trabecular cells, increased accumulation of extracellular matrix material (pigment and debris), and a decrease in the facility of aqueous outflow. This makes age a significant risk factor for the development of Primary Open Angle Glaucoma (POAG). **Analysis of Incorrect Options:** * **A. It is more common in males:** This is incorrect. Most epidemiological studies suggest that there is no significant gender predilection for IOP levels, although certain types of glaucoma (like Angle Closure Glaucoma) are actually more common in females. * **B. Diurnal variation is not present in glaucomatous patients:** This is incorrect. Diurnal variation is present in everyone, but it is **exaggerated** in glaucomatous patients. While a normal eye fluctuates by 3–5 mmHg, a glaucomatous eye often shows fluctuations >8–10 mmHg. * **C. There is no change in postural variations:** This is incorrect. IOP is dynamic and changes with posture; it typically **increases** when moving from a sitting/standing position to a supine (lying down) position due to increased episcleral venous pressure. **High-Yield Clinical Pearls for NEET-PG:** * **Normal IOP Range:** 10–21 mmHg (Mean: 15.5 ± 2.5 mmHg). * **Gold Standard Measurement:** Goldmann Applanation Tonometry (GAT). It is based on the **Imbert-Fick Law**. * **Diurnal Variation:** IOP is usually highest in the early morning (around 6:00 AM) and lowest in the evening. * **Central Corneal Thickness (CCT):** A thin cornea leads to an underestimation of IOP, while a thick cornea leads to an overestimation.

Q: Painful loss of vision is seen in which of the following conditions?

Primary open-angle glaucoma. **Explanation:** The correct answer is **B. Primary open-angle glaucoma (POAG)**. This question is a classic "except" style or "negative" identification question often found in NEET-PG. **Primary open-angle glaucoma (POAG)** is characteristically a **painless, progressive, and bilateral** loss of vision. It is often called the "silent thief of sight" because patients remain asymptomatic until significant peripheral visual field loss (tunnel vision) occurs. **Analysis of Options:** * **A. Senile Cataract:** Presents as a **painless**, gradual diminution of vision due to progressive opacification of the lens. * **C. Primary Angle-Closure Glaucoma (PACG):** This is a classic cause of **sudden, painful** loss of vision. It is an ocular emergency characterized by a mid-dilated non-reacting pupil, corneal edema, and very high intraocular pressure (IOP). * **D. Anterior Uveitis:** Presents with **pain**, photophobia, redness (ciliary congestion), and blurred vision. The pain is typically due to ciliary body spasm. **Clinical Pearls for NEET-PG:** * **Painless Loss of Vision:** POAG, Senile Cataract, Diabetic Retinopathy, Retinal Detachment (usually), and Central Retinal Vein Occlusion (CRVO). * **Painful Loss of Vision:** Acute Congestive Glaucoma (PACG), Anterior Uveitis, Optic Neuritis, and Endophthalmitis. * **POAG Triad:** IOP >21 mmHg, Optic disc cupping (Vertical cup-disc ratio >0.7), and characteristic visual field defects (e.g., Bjerrum’s scotoma). * **Drug of Choice for POAG:** Prostaglandin analogues (e.g., Latanoprost).

Question 1

What is the earliest visual field change in open-angle glaucoma?

Accepted Answer

Paracentral scotoma

Answer

Ring scotoma

Answer

Siedel's scotoma

Answer

Arcuate scotoma

Question 2

Tonography helps determine which of the following?

Accepted Answer

The facility of aqueous humor outflow.

Answer

The rate of aqueous humor formation.

Answer

The levels of intraocular pressure at different times.

Answer

None of the above.

Question 3

Neovascular glaucoma is not seen in which of the following conditions?

Accepted Answer

Juvenile Rheumatoid Arthritis (JRA)

Answer

Central Retinal Vein Occlusion (CRVO)

Answer

Central Retinal Artery Occlusion (CRAO)

Answer

Eales' disease

Question 4

Triple surgery in glaucoma includes all of the following except?

Accepted Answer

Insertion of drainage device

Answer

Trabeculectomy

Answer

PCIOL implantation

Answer

Extra capsular cataract extraction

Question 5

Which of the following conditions is the drug of choice for a topical beta blocker?

Accepted Answer

Open angle glaucoma

Answer

Angle closure glaucoma

Answer

Hypopyon corneal ulcer

Answer

Acute granulomatous uveitis

Question 6

Pilocarpine reduces intraocular pressure in persons with closed-angle glaucoma by:

Accepted Answer

Increasing aqueous humor outflow

Answer

Reducing aqueous humor secretion

Answer

Constricting iris sphincter muscle

Answer

Relaxing ciliary muscle

Question 7

Based on the perimetry result print-out, what is the most likely diagnosis?

Accepted Answer

Open angle glaucoma

Answer

Retinitis pigmentosa

Answer

Pituitary adenoma

Answer

Temporal lobe infarct

Question 8

What is the ideal treatment for subacute angle closure glaucoma?

Accepted Answer

Peripheral iridectomy

Answer

Timolol

Answer

Pilocarpine

Answer

Trabeculectomy

Question 9

Which of the following is true about intraocular pressure?

Accepted Answer

It increases with advancing age.

Answer

It is more common in males.

Answer

Diurnal variation is not present in glaucomatous patients.

Answer

There is no change in postural variations.

Question 10

Painful loss of vision is seen in which of the following conditions?

Accepted Answer

Primary open-angle glaucoma

Answer

Senile cataract

Answer

Primary angle-closure glaucoma

Answer

Anterior uveitis

Glaucoma — MCQs

Glaucoma — MCQs

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