Glaucoma — MCQs

Glaucoma Indian Medical PG Practice Questions and MCQs

Question 311: Which of the following is NOT a function of aqueous humor?

A. Maintenance of intraocular pressure
B. Providing nutrition to the lens and cornea (Correct Answer)
C. Maintaining the transparency of the cornea
D. Drainage of metabolic byproducts

Explanation: **Explanation** The question asks to identify which option is **NOT** a function of aqueous humor. However, based on physiological principles, options A, B, and D are all primary functions of aqueous humor. Option C is also a function, but it is secondary to the metabolic support provided. *Note: In the context of this specific question structure, there may be a typographical error in the provided key, as "Providing nutrition to the lens and cornea" is a **major** function of aqueous humor.* **1. Why Option B is the "Correct" Answer (Contextual Analysis):** Physiologically, aqueous humor **does** provide nutrition. If this is the intended answer, the question likely implies that while aqueous provides glucose and amino acids, the *primary* oxygenation for the cornea comes from the atmosphere (tears) and for the lens from the aqueous. However, in most standard textbooks, providing nutrition is a core function. **2. Analysis of Other Options:** * **A. Maintenance of IOP:** This is the most critical function. The balance between aqueous production (ciliary body) and outflow (trabecular/uveoscleral pathways) determines the intraocular pressure. * **C. Maintaining Transparency:** Aqueous humor maintains the hydration state of the cornea and lens. By providing a controlled chemical environment and removing waste, it prevents edema and opacification. * **D. Drainage of Metabolic Byproducts:** Since the lens and cornea are avascular, the aqueous acts as a "surrogate blood supply," carrying away lactic acid and other metabolites. **Clinical Pearls for NEET-PG:** * **Production:** Formed by the non-pigmented epithelium of the ciliary body via active transport (80%), ultrafiltration, and diffusion. * **Composition:** Compared to plasma, aqueous is **hypertonic**, highly acidic (low pH), and has a **high concentration of Ascorbate** (15x more than plasma) to protect against UV oxidation. It is significantly protein-poor. * **Conventional Outflow:** Trabecular meshwork → Canal of Schlemm → Episcleral veins (accounts for ~90% of drainage).

Question 312: Haab's striae are seen in which of the following conditions?

A. Buphthalmos (Correct Answer)
B. Keratoglobus
C. Trachoma
D. Keratoconus

Explanation: **Explanation:** **Haab’s striae** are horizontal or curvilinear breaks in the **Descemet’s membrane** caused by sudden stretching of the cornea due to increased intraocular pressure (IOP). 1. **Why Buphthalmos is correct:** Buphthalmos (Congenital Glaucoma) occurs when elevated IOP causes the infant’s elastic sclera and cornea to enlarge. As the cornea stretches, the rigid Descemet’s membrane cannot keep pace and ruptures, resulting in Haab’s striae. These are typically **horizontal** (when central) or **concentric** with the limbus (when peripheral). 2. **Why other options are incorrect:** * **Keratoglobus:** Characterized by generalized thinning and protrusion of the entire cornea, but it does not typically present with Haab’s striae. * **Trachoma:** Leads to Arlt’s line (conjunctival scarring) and Herbert’s pits (limbal scarring), not Descemet’s breaks. * **Keratoconus:** Features **Vogt’s striae**, which are fine, **vertical** stress lines in the deep stroma/Descemet’s membrane that disappear upon applying pressure to the globe. **High-Yield Clinical Pearls for NEET-PG:** * **Haab’s Striae vs. Vogt’s Striae:** Remember **H**aab’s are **H**orizontal (Buphthalmos); **V**ogt’s are **V**ertical (Keratoconus). * **Triad of Congenital Glaucoma:** Photophobia, Blepharospasm, and Lacrimation (Epiphora). * **Corneal Diameter:** In Buphthalmos, the diameter is usually >12 mm before age 1. * **Management:** The primary treatment for Buphthalmos is surgical (Goniotomy or Trabeculotomy).

Question 313: Malignant glaucoma is characterized by which of the following?

A. Anterior chamber is normal
B. Misdirected aqueous flow (Correct Answer)
C. Pilocarpine is the drug of choice
D. Management is medical only

Explanation: **Malignant Glaucoma (Aqueous Misdirection Syndrome)** is a rare but serious complication typically occurring after intraocular surgery in eyes with pre-existing primary angle-closure glaucoma. ### **Explanation of the Correct Answer** **B. Misdirected aqueous flow:** The hallmark of this condition is the posterior diversion of aqueous humor into or behind the vitreous cavity. This creates pressure that pushes the lens-iris diaphragm forward, leading to a shallowing of the anterior chamber and a secondary rise in intraocular pressure (IOP). ### **Why Other Options are Incorrect** * **A. Anterior chamber is normal:** In malignant glaucoma, the anterior chamber is **uniformly shallow or flat** (axial shallowing), which distinguishes it from pupillary block where the central chamber depth is often preserved. * **C. Pilocarpine is the drug of choice:** Pilocarpine is **contraindicated**. It causes miosis and forward movement of the lens-iris diaphragm, further worsening the shallowing of the anterior chamber. * **D. Management is medical only:** While medical management is the first line, it often fails. Definitive treatment frequently requires surgical intervention, such as **Nd:YAG laser capsulotomy/hyaloidotomy** or **Pars Plana Vitrectomy** to break the cycle of misdirection. ### **High-Yield Clinical Pearls for NEET-PG** * **Drug of Choice:** **Atropine (1%)** is the mainstay of medical treatment. It acts as a cycloplegic, relaxing the ciliary muscle and pulling the lens-iris diaphragm backward. * **Classic Presentation:** A patient with a history of glaucoma surgery who presents with a flat anterior chamber and high IOP despite a patent peripheral iridectomy. * **Medical Management (The "Malignant Glaucoma Cocktail"):** Atropine (cycloplegic), Acetazolamide/Mannitol (to reduce vitreous volume), and Timolol (to decrease aqueous production). * **Key Diagnostic Feature:** Absence of choroidal detachment on B-scan ultrasonography (helps rule out suprachoroidal hemorrhage).

Question 314: In angle closure glaucoma, what mainly causes obstruction to the outflow of aqueous humor?

A. Canal of Schlemm
B. Trabecular meshwork
C. Iris (Correct Answer)
D. Scleral venous plexus

Explanation: ### Explanation In **Angle Closure Glaucoma (ACG)**, the fundamental pathology is a mechanical obstruction of the drainage angle by the **peripheral iris**. **Why Iris is the Correct Answer:** The primary mechanism involves the iris being pushed or pulled against the trabecular meshwork. In most cases, this is triggered by **pupillary block**, where resistance to aqueous flow from the posterior to the anterior chamber increases pressure behind the iris. This causes the iris to bow forward (**iris bombé**), physically apposing the peripheral iris to the cornea and blocking access to the drainage structures. Therefore, the iris acts as the "door" that closes the "drain." **Why Other Options are Incorrect:** * **Trabecular Meshwork (B):** While this is the site of resistance in *Open Angle Glaucoma (OAG)* due to microscopic degenerative changes, in ACG, the meshwork itself is often healthy but becomes inaccessible because the iris covers it. * **Canal of Schlemm (A) and Scleral Venous Plexus (D):** These are distal components of the outflow pathway. They do not cause the primary obstruction in ACG; they are simply deprived of aqueous because the fluid cannot reach them. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factors:** Hypermetropia (small eyes), shallow anterior chambers, and increasing age (thickening lens). * **Classic Presentation:** Sudden onset of severe pain, "halos" around lights (due to corneal edema), and a mid-dilated, vertically oval, non-reactive pupil. * **Gold Standard Diagnosis:** **Gonioscopy** is essential to visualize the angle and differentiate between open and closed-angle mechanisms. * **Definitive Treatment:** **Laser Peripheral Iridotomy (LPI)**, which bypasses the pupillary block by creating a hole in the iris.

Question 315: All of the following causes coloured halos except?

A. Corneal edema
B. Retinal degeneration (Correct Answer)
C. Foreign body
D. Steroids

Explanation: **Explanation:** The phenomenon of **coloured halos** (rainbow-like rings around lights) is primarily caused by the **diffraction of light** as it passes through a hazy or irregular medium in the eye. **Why Retinal Degeneration is the Correct Answer:** Retinal degeneration involves the loss of photoreceptors or atrophy of the retinal pigment epithelium. Since the pathology is located at the **neurosensory level (the "film" of the camera)** and not in the transparent media, it does not cause diffraction. Therefore, it does not produce coloured halos. **Analysis of Incorrect Options:** * **Corneal Edema (Option A):** This is the most common cause (e.g., in Acute Congestive Glaucoma). Fluid accumulation in the corneal epithelium and stroma acts like a diffraction grating, splitting white light into its spectral colors. * **Foreign Body (Option C):** A foreign body on the cornea or within the precorneal tear film disrupts the smooth refractive surface, leading to light scattering and halo formation. * **Steroids (Option D):** Prolonged steroid use is a known risk factor for **Steroid-induced Glaucoma** (causing corneal edema) and **Posterior Subcapsular Cataract**. Both conditions cause light diffraction and subsequent halos. **NEET-PG High-Yield Pearls:** 1. **Fincham’s Test:** Used to differentiate halos of Glaucoma from Cataract. When a stenopaeic slit is moved across the pupil, **glaucomatous halos remain intact**, whereas **cataractous halos break into segments**. 2. **Differential Diagnosis of Halos:** * **Glaucoma:** Due to corneal edema (High IOP). * **Cataract:** Due to irregular refractive indices in the lens. * **Mucus on Cornea:** Halos disappear after blinking or washing the eye. 3. **Order of Colors:** In diffraction halos (like Glaucoma), **blue is innermost** and **red is outermost**.

Question 316: Glaucoma is caused by?

A. Raised intraocular pressure (Correct Answer)
B. Raised intracranial pressure
C. Intraocular infection
D. Orbital mass

Explanation: **Explanation:** **Glaucoma** is a group of eye conditions characterized by progressive optic neuropathy, where the primary risk factor and causative agent is **raised intraocular pressure (IOP)**. The elevated pressure (typically >21 mmHg) causes mechanical compression and ischemic damage to the retinal ganglion cells and the optic nerve head, leading to characteristic optic disc cupping and visual field defects. **Analysis of Options:** * **A. Raised Intraocular Pressure (Correct):** This is the hallmark of glaucoma. It usually results from an imbalance between the production of aqueous humor by the ciliary body and its drainage through the trabecular meshwork or uveoscleral pathway. * **B. Raised Intracranial Pressure:** This leads to **Papilledema** (bilateral optic disc swelling), not glaucoma. While both involve the optic nerve, the mechanism and clinical presentation are distinct. * **C. Intraocular Infection:** This typically results in **Endophthalmitis** or **Uveitis**. While secondary glaucoma can occur *due* to inflammation (e.g., inflammatory cells clogging the trabecular meshwork), infection itself is not the definition or primary cause of glaucoma. * **D. Orbital Mass:** This may cause **Proptosis** (bulging of the eye) or compressive optic neuropathy, but it is not the causative mechanism for glaucoma. **High-Yield Clinical Pearls for NEET-PG:** * **Normal IOP:** 10–21 mmHg (measured via Goldmann Applanation Tonometry, the gold standard). * **The "Triad" of Glaucoma:** Raised IOP, Optic disc cupping, and Visual field defects (e.g., Bjerrum’s scotoma). * **Normal Tension Glaucoma (NTG):** A variant where glaucomatous damage occurs despite IOP being within the statistically normal range. * **Drug of Choice:** Prostaglandin analogues (e.g., Latanoprost) are the first-line medical treatment for Open-Angle Glaucoma.

Question 317: An elderly female presents with sudden onset of pain, redness, and decreased vision. On examination, hazy cornea, fixed mid-dilated pupil, and shallow anterior chamber are noted. What is the diagnosis?

A. Central retinal artery occlusion
B. Acute conjunctivitis
C. Acute congestive glaucoma (Correct Answer)
D. Acute uveitis

Explanation: ***Acute congestive glaucoma (Acute angle-closure glaucoma)*** - This presentation is **classic** for acute angle-closure glaucoma with all hallmark features present - **Sudden onset** of severe pain, redness, and decreased vision due to rapidly elevated intraocular pressure (IOP) - **Hazy/edematous cornea** results from corneal epithelial edema secondary to extremely high IOP (often >40-60 mmHg) - **Fixed mid-dilated pupil** occurs due to iris ischemia and pupillary sphincter paralysis from pressure-induced vascular compromise - **Shallow anterior chamber** is the anatomical predisposition that precipitates angle closure, more common in elderly hypermetropic individuals - This is an **ophthalmic emergency** requiring immediate IOP reduction *Acute uveitis* - Presents with pain, redness, and photophobia, but key differentiating features are absent - Typically has a **miotic (constricted) pupil** due to ciliary spasm, not a fixed mid-dilated pupil - Cornea is usually **clear** unless there is associated keratitis; hazy cornea is not a characteristic feature - Anterior chamber is **deep or normal depth**, not shallow - Classic findings include **keratic precipitates**, cells and flare in anterior chamber on slit-lamp examination *Acute conjunctivitis* - Presents with redness, discharge, and foreign body sensation - Vision is typically **preserved** or only mildly affected - **No pain** (only mild irritation), cornea remains clear, pupil is normal and reactive - Anterior chamber depth is normal - The severe pain and anterior segment findings (hazy cornea, fixed pupil, shallow AC) rule this out *Central retinal artery occlusion (CRAO)* - Presents with **sudden, painless, profound vision loss** (classically "curtain coming down") - **Anterior segment is completely normal** — no corneal haze, normal pupil reactions (may have RAPD), normal AC depth - Fundoscopy shows **cherry-red spot** at macula, pale retina, and attenuated vessels - The presence of pain and anterior segment abnormalities excludes this diagnosis

Question 318: The image shows findings diagnostic of glaucoma: Cupping of disc, Double angulation of blood vessels (visible in middle), one in steep wall of excavation and second in floor of the cup. Nasal shifting of vessels. Thinning of neural rim on temporal side.

A. Glaucoma (Correct Answer)
B. Optic atrophy
C. Physiological cupping
D. Ischemic optic neuropathy

Explanation: ***Glaucoma (Correct Answer)*** - The image shows **characteristic findings of glaucomatous optic neuropathy**: significant **cupping of the optic disc** due to retinal ganglion cell loss - **Double angulation of blood vessels** (bayoneting sign) - vessels bend acutely over the steep wall of the cup and again at the floor - **Nasal shifting of vessels** - blood vessels appear to hug the nasal side as the cup expands temporally - **Thinning of the neural rim on temporal side** - violation of ISNT rule (Inferior > Superior > Nasal > Temporal rim thickness in normal discs) - These features together are **pathognomonic for glaucoma** *Optic Atrophy (Incorrect)* - Shows **disc pallor** as the primary feature with loss of pink color - May have cupping but lacks the **characteristic double angulation** and **nasal shifting of vessels** seen in glaucoma - Typically caused by chronic optic nerve damage from various etiologies (ischemia, compression, inflammation) *Physiological Cupping (Incorrect)* - Large cup-to-disc ratio (>0.3) present since birth without pathology - Cup remains **symmetric and uniform** without preferential temporal or vertical rim thinning - No progressive enlargement on follow-up and **normal visual fields** - Lacks the **double angulation, nasal displacement**, and asymmetric rim loss characteristic of glaucomatous cupping *Ischemic Optic Neuropathy (Incorrect)* - Presents acutely with **disc edema** initially (swollen, hyperemic disc) - Later shows **diffuse pallor** rather than excavation/cupping - Typically has **altitudinal visual field defects** rather than the arcuate defects of glaucoma - Does not demonstrate the **progressive cupping with vessel changes** seen in chronic glaucoma

Question 319: The image shows a funnel shaped anterior chamber (deeper in the center and narrow in the periphery), which is seen in angle closure glaucoma. This is caused by:

A. Anterior synechiae
B. Posterior synechiae
C. Iris bombe (Correct Answer)
D. Pupillary block

Explanation: ***Iris bombe*** - **Iris bombe** occurs when there is a 360-degree adhesion between the iris and the lens (or anterior vitreous in aphakic/pseudophakic eyes), preventing aqueous humor from flowing from the posterior chamber to the anterior chamber. - This build-up of aqueous humor in the posterior chamber pushes the entire iris anteriorly, creating a **funnel-shaped anterior chamber** that is deeper centrally and shallow peripherally, leading to angle closure. *Anterior synechiae* - **Anterior synechiae** are adhesions between the iris and the cornea or trabecular meshwork, directly closing the angle. - While they cause **angle closure**, they are a consequence of the iris being pushed forward rather than the primary cause of the iris bowing shown. *Posterior synechiae* - **Posterior synechiae** are adhesions between the iris and the lens, specifically at the pupillary margin. - When these adhesions are 360 degrees, they precisely lead to **iris bombe** by blocking aqueous flow from the posterior to the anterior chamber. *Pupillary block* - **Pupillary block** is the mechanism by which aqueous flow is obstructed at the pupil. - It describes the functional blockage and is the underlying cause for the anatomical manifestation of **iris bombe**.

Question 320: A patient with cataract presents with pain and redness of eye. On examination he had deep anterior chamber. What is the diagnosis?

A. Acute phacolytic glaucoma (Correct Answer)
B. Acute angle closure glaucoma
C. Acute neovascular glaucoma
D. Acute phacomorphic glaucoma

Explanation: ***Acute phacolytic glaucoma*** - This condition occurs when **lens proteins leak** from a mature or hypermature cataract into the aqueous humor, causing an inflammatory reaction and **trabecular meshwork obstruction**, leading to elevated intraocular pressure. - The presence of a **deep anterior chamber** distinguishes it from phacomorphic glaucoma, which is characterized by a shallow anterior chamber due to lens intumescence. *Acute angle closure glaucoma* - This typically presents with a **shallow anterior chamber** as the iris bows forward, blocking the trabecular meshwork. - While it causes pain and redness, the deep anterior chamber described in the patient makes this diagnosis unlikely. *Acute neovascular glaucoma* - This type of glaucoma results from the formation of **new blood vessels** on the iris and in the angle of the anterior chamber, often due to conditions like **diabetic retinopathy** or **retinal vein occlusion**. - There is no mention of such predisposing factors or visible neovascularization in the patient's presentation. *Acute phacomorphic glaucoma* - This condition is caused by the **intumescence (swelling) of a cataractous lens**, which pushes the iris forward, leading to a **shallow anterior chamber** and angle closure. - The patient's presentation of a **deep anterior chamber** rules out phacomorphic glaucoma.

Practice by Chapter

Aqueous Humor Dynamics

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Primary Open-Angle Glaucoma

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Primary Angle-Closure Glaucoma

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Secondary Open-Angle Glaucomas

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Secondary Angle-Closure Glaucomas

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Developmental and Congenital Glaucomas

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Medical Management of Glaucoma

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Laser Therapy in Glaucoma

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Glaucoma Filtration Surgery

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Glaucoma Drainage Devices

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Angle Assessment Techniques

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Visual Field Testing in Glaucoma

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Glaucoma — MCQs

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