Glaucoma — MCQs

Glaucoma Indian Medical PG Practice Questions and MCQs

Question 131: What is the treatment of choice for the other eye in angle closure glaucoma?

A. Laser trabeculoplasty
B. Trabeculectomy
C. Laser iridotomy (Correct Answer)
D. Peripheral iridectomy

Explanation: **Explanation:** In Primary Angle Closure Glaucoma (PACG), the underlying pathology is typically **pupillary block**, which causes a pressure gradient between the posterior and anterior chambers, leading to iris bombe and closure of the drainage angle. **Why Laser Iridotomy is the Correct Answer:** Angle-closure glaucoma is considered a bilateral disease. If one eye has suffered an acute attack, the fellow eye (the "other eye") has a **50-70% risk** of developing an acute attack within five years due to similar anatomical predispositions (shallow anterior chamber, narrow angles). **Laser Peripheral Iridotomy (LPI)** is the treatment of choice because it creates a hole in the peripheral iris, equalizing pressure between the chambers and bypassing the pupillary block. It is performed prophylactically to prevent a future acute attack. **Analysis of Incorrect Options:** * **A. Laser trabeculoplasty:** Used primarily in Open Angle Glaucoma (POAG) to increase aqueous outflow through the trabecular meshwork. It is ineffective in closed angles where the meshwork is physically obstructed by the iris. * **B. Trabeculectomy:** A surgical filtering procedure used when medical or laser therapy fails to control intraocular pressure. It is too invasive for a prophylactic "other eye" treatment. * **D. Peripheral iridectomy:** This is a surgical procedure. While it achieves the same goal as LPI, it is now reserved for cases where laser treatment is not possible (e.g., corneal edema or lack of equipment). Laser is the modern "gold standard." **High-Yield Clinical Pearls for NEET-PG:** * **Prophylactic LPI** is mandatory for the fellow eye in PACG. * **Drug of choice** to rapidly lower IOP in acute attack: IV Mannitol or Acetazolamide. * **Definitive treatment** for the affected eye: Laser Peripheral Iridotomy (once the cornea is clear). * **Anatomical risk factors:** Hypermetropia, small eyeball, thick lens, and shallow anterior chamber.

Question 132: Frequent changes of reading glasses in a 60-year-old male patient is a feature of which of the following conditions?

A. Primary open-angle glaucoma (Correct Answer)
B. Senile nuclear cataract
C. Acute angle-closure glaucoma
D. Presbyopia

Explanation: **Explanation:** **Primary Open-Angle Glaucoma (POAG)** is the correct answer because "frequent changes of reading glasses" is a classic early symptom of this condition. This occurs due to **increased intraocular pressure (IOP)** causing pressure on the ciliary body. This leads to **ciliary muscle weakness** and a subsequent decrease in the amplitude of accommodation. As the eye loses its ability to focus on near objects faster than normal aging would dictate, the patient requires frequent increases in the power of their presbyopic correction. **Analysis of Incorrect Options:** * **Senile Nuclear Cataract:** This typically causes a "second sight" phenomenon. The increasing density of the nucleus increases the refractive index of the lens, leading to **index myopia**. This may actually allow a presbyopic patient to read *without* glasses temporarily, rather than needing frequent changes. * **Acute Angle-Closure Glaucoma:** This is an ocular emergency presenting with sudden, severe pain, redness, blurred vision, and colored halos. It is not a chronic condition characterized by subtle changes in spectacle power. * **Presbyopia:** While this causes a need for reading glasses, it is a gradual, age-related physiological process. A "frequent" or rapid change in power (e.g., every few months) is pathological and should alert the clinician to POAG. **Clinical Pearls for NEET-PG:** * **Early Symptoms of POAG:** Often asymptomatic ("Silent thief of sight"), but may present with frequent change of glasses, delayed dark adaptation, or mild headaches. * **Triad of POAG:** 1. Raised IOP (>21 mmHg), 2. Optic disc cupping, 3. Characteristic visual field defects (e.g., Bjerrum’s scotoma). * **High-Yield Fact:** In any elderly patient complaining of frequent changes in near vision power, always perform **tonometry** and **fundus examination** to rule out POAG.

Question 133: Which of the following is not useful in chronic open-angle glaucoma?

A. Prostaglandin analogue
B. Pilocarpine
C. Homatropine (Correct Answer)
D. Timolol

Explanation: **Explanation:** The goal of treating **Chronic Open-Angle Glaucoma (COAG)** is to lower intraocular pressure (IOP) by either decreasing aqueous humor production or increasing its outflow. **Why Homatropine is the correct answer:** Homatropine is a **mydriatic-cycloplegic** (anticholinergic) agent. It works by paralyzing the ciliary muscle and the sphincter pupillae. In the context of glaucoma, mydriatics are generally **contraindicated** or not useful because they can cause pupillary dilation, which potentially crowds the anterior chamber angle. Furthermore, by paralyzing the ciliary muscle, they decrease the tension on the trabecular meshwork, which can actually **reduce** aqueous outflow and increase IOP. Homatropine is primarily used for refraction or treating anterior uveitis, not COAG. **Analysis of incorrect options:** * **Prostaglandin Analogues (e.g., Latanoprost):** These are the **first-line** treatment for COAG. They work by increasing the uveoscleral outflow of aqueous humor. * **Pilocarpine:** A miotic (cholinergic) agent. It contracts the ciliary muscle, which pulls on the scleral spur and opens the spaces in the trabecular meshwork, thereby increasing aqueous outflow. While less commonly used today due to side effects, it is a valid treatment. * **Timolol:** A topical beta-blocker that reduces IOP by **decreasing the production** of aqueous humor from the ciliary body. It remains a mainstay of glaucoma therapy. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC) for COAG:** Prostaglandin Analogues (most potent, once-daily dosing). * **Mechanism of PG Analogues:** Increase uveoscleral outflow. * **Side effect of PG Analogues:** Iris hyperpigmentation and thickening/lengthening of eyelashes. * **Contraindication for Beta-blockers:** Avoid Timolol in patients with Asthma or Heart Block.

Question 134: Von Recklinghausen disease is associated with which of the following?

A. Glaucoma
B. Optic nerve glioma
C. Neurofibroma of the lids
D. All the above (Correct Answer)

Explanation: **Explanation:** **Von Recklinghausen disease**, also known as **Neurofibromatosis Type 1 (NF1)**, is a multisystem neuroectodermal disorder with significant ophthalmic manifestations. The correct answer is **"All the above"** because NF1 affects multiple ocular structures: 1. **Glaucoma (Option A):** Glaucoma occurs in about 1 in 300 NF1 patients. It is typically unilateral and congenital. The mechanism is multifactorial, involving neurofibromatous infiltration of the anterior chamber angle, developmental angle anomalies, or secondary angle closure due to ciliary body neurofibromas. 2. **Optic Nerve Glioma (Option B):** This is a hallmark feature of NF1, occurring in approximately 15% of patients. These are typically low-grade pilocytic astrocytomas. While often asymptomatic, they can cause progressive vision loss and proptosis. 3. **Neurofibroma of the Lids (Option C):** **Plexiform neurofibromas** are pathognomonic for NF1. When they involve the upper eyelid, they produce a characteristic S-shaped deformity and mechanical ptosis. **Clinical Pearls for NEET-PG:** * **Lisch Nodules:** These are the most common ocular finding in NF1 (melanocytic hamartomas of the iris). They appear as raised, tan-colored spots and do not affect vision. * **Sphenoid Wing Dysplasia:** A skeletal abnormality in NF1 that can cause pulsating exophthalmos. * **Rule of Thumb:** If a patient has a plexiform neurofibroma of the eyelid, there is a significantly higher risk of associated ipsilateral congenital glaucoma. * **Diagnostic Criteria:** Remember the "CAFÉ" mnemonic (Café-au-lait spots, Axillary freckling, Fibromas, Eye findings like Lisch nodules/Optic gliomas).

Question 135: What type of laser is used in laser iridotomy?

A. CO2 laser
B. Nd Yag laser (Correct Answer)
C. Excimer laser
D. KTP laser

Explanation: **Explanation:** **Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser** is the gold standard for performing a peripheral iridotomy (LPI). It is a **solid-state, photodisruptive laser** that works by creating a localized shockwave to punch a hole through the iris tissue. This creates an alternative pathway for aqueous humor to flow from the posterior to the anterior chamber, effectively bypassing pupillary block in Angle-Closure Glaucoma. **Analysis of Options:** * **Nd:YAG Laser (Correct):** Operates at a wavelength of **1064 nm** (infrared). It is preferred because it is non-thermal and can penetrate even dark, thick irides effectively. * **CO2 Laser:** Primarily used in dermatology and ENT for cutting or vaporizing tissue. It has high water absorption and is not used intraocularly for glaucoma. * **Excimer Laser:** A "cool" ultraviolet laser used in refractive surgeries like **LASIK and PRK** to reshape the cornea by photoablation. * **KTP (Potassium Titanyl Phosphate) Laser:** A frequency-doubled Nd:YAG (532 nm) that produces green light. It is used for photocoagulation (like retinal procedures) but is not the primary choice for iridotomy. **High-Yield Clinical Pearls for NEET-PG:** 1. **Indications:** Primary Angle Closure (PAC), PAC Glaucoma, and the fellow eye of a patient with an acute attack. 2. **Pre-procedure Medication:** **Pilocarpine** is used to stretch the iris (making it thinner and easier to penetrate) and **Apraclonidine/Brimonidine** to prevent post-laser IOP spikes. 3. **Preferred Site:** Usually placed in the superior periphery (11 or 1 o'clock) to be covered by the upper eyelid, preventing "ghost images" or diplopia. 4. **Complication:** The most common immediate complication is a transient **IOP spike** and localized **hyphema** (bleeding from the iris).

Question 136: A 60-year-old woman with primary open-angle glaucoma presents with a specific visual field defect. Which part of the visual field is most resistant to progressive glaucomatous visual field loss?

A. Central vision
B. Nasal peripheral vision
C. Superior vision
D. Temporal peripheral vision (Correct Answer)

Explanation: ### Explanation In Primary Open-Angle Glaucoma (POAG), the pattern of visual field loss follows the specific anatomy of the retinal nerve fiber layer (RNFL). The correct answer is **Temporal peripheral vision** (specifically the temporal island of vision). **Why it is correct:** Glaucomatous damage typically starts in the arcuate fibers (superior and inferior poles of the optic disc), leading to nasal steps and arcuate scotomas. As the disease progresses, the central field is eventually lost. However, the nerve fibers originating from the **nasal retina** (which represent the **temporal peripheral visual field**) are the most resistant to elevated intraocular pressure. Consequently, in advanced or end-stage glaucoma, a small "temporal island" of vision often persists even after the central vision is extinguished. **Why other options are incorrect:** * **Central vision:** While often preserved until late stages (forming a "tubular field"), it is generally lost *before* the temporal peripheral island in terminal glaucoma. * **Nasal peripheral vision:** This is usually the **earliest** area to show defects (e.g., Roenne’s nasal step) because the superior and inferior temporal nerve fibers are most vulnerable. * **Superior vision:** This is frequently affected early in the disease process due to the susceptibility of the inferior pole of the optic nerve head. **High-Yield Clinical Pearls for NEET-PG:** * **Sequence of loss:** Peripheral nasal field → Arcuate areas → Central field → Temporal peripheral field (last to go). * **10-2 Perimetry:** Used to monitor patients with advanced glaucoma when only a small central island remains. * **Splinter Hemorrhage (Drance Hemorrhage):** Often seen at the disc margin in POAG; a sign of active progression. * **ISNT Rule:** In a normal eye, the thickness of the neuroretinal rim follows Inferior > Superior > Nasal > Temporal. Glaucoma often causes a "notching" that breaks this rule.

Question 137: In chronic simple glaucoma, what is the most common visual field defect?

A. Arcuate field defect
B. Baring of the blind spot (Correct Answer)
C. Bjerrum scotoma
D. Seidel's sign

Explanation: In Chronic Simple Glaucoma (Primary Open Angle Glaucoma), visual field defects follow a specific chronological progression as nerve fiber layer damage advances. ### **Explanation of the Correct Answer** **Baring of the blind spot** is considered the **earliest** and **most common** clinically detectable visual field change in glaucoma. It occurs due to generalized depression of the field, where the physiological blind spot is no longer connected to the central area of vision by an isopter. While it is the most common early sign, it is important to note that it is **non-specific** and can occur in other conditions (like aging or small pupils). ### **Analysis of Incorrect Options** * **C. Bjerrum scotoma:** This is a late-stage arcuate defect. It is a comet-shaped scotoma extending from the blind spot, sweeping above or below the fixation point to end at the nasal horizontal meridian. It is more characteristic of established glaucoma rather than being the most common early sign. * **D. Seidel’s sign:** This is an early arcuate defect where a sickle-shaped extension occurs from the upper or lower pole of the blind spot. It precedes the Bjerrum scotoma. * **A. Arcuate field defect:** This is a general term for defects following the path of the arcuate nerve fibers. While highly characteristic of glaucoma, "baring of the blind spot" typically precedes the formation of a full arcuate defect. ### **Clinical Pearls for NEET-PG** * **Sequence of defects:** Baring of blind spot → Small wing-shaped Paracentral scotoma → Seidel’s scotoma → Bjerrum/Arcuate scotoma → Double Arcuate (Ring) scotoma → Roenne’s Nasal Step → Tubular vision → Total blindness. * **Tubular Vision:** This is the terminal stage where only a small central island of vision remains. * **High-Yield Fact:** The **nasal field** is usually affected before the temporal field in glaucoma.

Question 138: Atropine is contraindicated in which of the following conditions?

A. Narrow angle glaucoma (Correct Answer)
B. Open angle glaucoma
C. Congenital glaucoma
D. Steroid induced glaucoma

Explanation: **Explanation:** **Why Narrow-Angle Glaucoma (NAG) is the correct answer:** Atropine is a potent **parasympatholytic (mydriatic)** agent. In patients with narrow anterior chamber angles, pupillary dilation causes the peripheral iris to bunch up and thicken at the iris base. This physically blocks the trabecular meshwork (the drainage site), leading to a sudden rise in intraocular pressure (IOP) and precipitating an **Acute Angle Closure Glaucoma** crisis. Therefore, it is strictly contraindicated. **Analysis of Incorrect Options:** * **Open-Angle Glaucoma (OAG):** The pathology lies within the microscopic resistance of the trabecular meshwork, not the physical position of the iris. While atropine can slightly increase IOP in OAG by reducing aqueous outflow, it does not cause an acute crisis like in NAG. * **Congenital Glaucoma:** This is caused by developmental anomalies of the angle (e.g., Barkan’s membrane). Atropine is not the treatment, but it is not a primary contraindication in the same way it is for NAG. * **Steroid-Induced Glaucoma:** This is a form of secondary OAG caused by increased resistance to aqueous outflow due to structural changes in the trabecular meshwork. It is managed by stopping steroids, not by avoiding mydriatics. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for NAG:** IV Mannitol and Acetazolamide (to lower IOP) followed by **Pilocarpine** (miotic) once IOP is stabilized. * **Definitive Treatment for NAG:** Peripheral Iridotomy (usually via YAG laser). * **Mydriatic of Choice for Fundus Examination:** Tropicamide (shorter duration of action) is preferred over Atropine, but even it must be used with caution if the angle is narrow. * **Safe Mydriatic:** Phenylephrine (sympathomimetic) is often safer as it is easier to reverse, but the risk of angle closure still exists.

Question 139: What is the preferred drug for acute angle closure glaucoma?

A. Beta-blocker
B. Pilocarpine (Correct Answer)
C. Atropine
D. None of the above

Explanation: **Explanation:** **Pilocarpine** is the definitive medical treatment for acute angle-closure glaucoma (AACG) because it is a **miotic (parasympathomimetic)**. In AACG, the peripheral iris obstructs the trabecular meshwork. Pilocarpine causes contraction of the iris sphincter muscle, which pulls the peripheral iris away from the angle, physically opening the drainage pathway and allowing aqueous humor to exit. *Note:* In very high intraocular pressure (IOP > 40-50 mmHg), the iris sphincter becomes ischemic and unresponsive to pilocarpine. Therefore, systemic hyperosmotics (like Mannitol) or Acetazolamide are often given first to lower IOP before pilocarpine can work effectively. **Why other options are incorrect:** * **Beta-blockers (e.g., Timolol):** While they help reduce aqueous production, they do not address the primary anatomical pathology (the closed angle). They are used as adjunctive therapy, not the definitive drug of choice. * **Atropine:** This is a **mydriatic** (dilates the pupil). It is strictly **contraindicated** in AACG because pupillary dilation further bunches the iris into the angle, worsening the blockage and potentially blinding the patient. **Clinical Pearls for NEET-PG:** * **Drug of choice to rapidly lower IOP:** Intravenous Mannitol (Hyperosmotic). * **Definitive/Permanent Treatment:** Laser Peripheral Iridotomy (LPI) – performed on both the affected and the fellow (prophylactic) eye. * **Classic Presentation:** "Halos around lights," "steamy cornea," and a "mid-dilated non-reactive pupil." * **Pilocarpine Side Effect:** Can cause "brow ache" due to ciliary muscle contraction.

Question 140: A coloured halo is seen in all conditions except:

A. Open angle glaucoma (Correct Answer)
B. Closed angle glaucoma
C. Cataract
D. None of the above

Explanation: **Explanation:** The perception of **colored halos** (iridescent vision) around lights is a clinical phenomenon caused by the diffraction of light as it passes through an edematous cornea or a lens with structural changes. **1. Why Open Angle Glaucoma (OAG) is the correct answer:** In **Primary Open Angle Glaucoma**, the rise in intraocular pressure (IOP) is typically slow, chronic, and painless. The corneal endothelium is usually able to compensate for this gradual rise, preventing significant corneal edema. Since the cornea remains clear and dehydrated, light diffraction does not occur, and colored halos are **not** a feature of OAG. **2. Analysis of other options:** * **Closed Angle Glaucoma:** During an acute attack, the IOP rises rapidly and severely. This overwhelms the corneal endothelial pump, leading to **corneal edema** (accumulation of fluid in the epithelial cells). This fluid acts as a diffraction grating, splitting white light into its spectral components (the "Fincham’s Test" can differentiate this from cataract). * **Cataract:** In early stages (immature or nuclear cataract), irregular refractive indices in the lens fibers or water clefts cause light scattering, leading to the perception of halos. **Clinical Pearls for NEET-PG:** * **Fincham’s Test:** Used to differentiate halos of glaucoma from cataract. If a stenopeic slit is passed across the pupil, glaucomatous halos remain intact, whereas cataractous halos break into segments. * **Differential Diagnosis of Halos:** Acute Congestive Glaucoma, Cataract, Mucopurulent Conjunctivitis (due to flakes of mucus on the cornea), and Corneal Edema (e.g., Fuch’s dystrophy). * **Key Distinction:** Halos in glaucoma are typically seen when the IOP exceeds 30-40 mmHg suddenly.

Practice by Chapter

Aqueous Humor Dynamics

Practice Questions

Primary Open-Angle Glaucoma

Practice Questions

Primary Angle-Closure Glaucoma

Practice Questions

Secondary Open-Angle Glaucomas

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Secondary Angle-Closure Glaucomas

Practice Questions

Developmental and Congenital Glaucomas

Practice Questions

Medical Management of Glaucoma

Practice Questions

Laser Therapy in Glaucoma

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Glaucoma Filtration Surgery

Practice Questions

Glaucoma Drainage Devices

Practice Questions

Angle Assessment Techniques

Practice Questions

Visual Field Testing in Glaucoma

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Glaucoma — MCQs

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