Glaucoma Practice Questions

Q: A 60-year-old male presents with colored halos around lights. The most probable diagnosis is

Acute angle closure glaucoma. ***Acute angle closure glaucoma*** - **Colored halos (rainbow-colored)** around lights are a classic and pathognomonic symptom of **acute angle closure glaucoma**, caused by corneal edema secondary to elevated intraocular pressure. - The edematous cornea acts as a **prism**, breaking white light into its spectral colors, producing the characteristic rainbow halos. - These colored halos can occur as **prodromal symptoms** before a full acute attack, and may be present even without severe eye pain, especially in subacute or intermittent angle closure. - The patient's age (60 years) fits the typical demographic, as angle closure glaucoma is more common in older adults, hypermetropes, and those with shallow anterior chambers. *Senile immature cataract* - Cataracts typically cause **monochromatic (white) halos** or glare around lights due to light scattering by lens opacities, not the colored/rainbow halos described. - The predominant symptoms of cataracts are **progressive blurred vision**, difficulty with night driving, and glare, rather than colored halos. - While cataracts are common at age 60, the specific symptom of colored halos does not point to this diagnosis. *Chronic open angle glaucoma* - This is typically **asymptomatic** in early stages and presents with gradual **peripheral vision loss** and optic nerve cupping. - Colored halos are not a characteristic feature of chronic open angle glaucoma, as IOP elevation is usually gradual and does not cause significant corneal edema. *Bacterial conjunctivitis* - Presents with **redness, discharge, irritation**, and foreign body sensation due to conjunctival inflammation. - Does not cause visual disturbances like colored halos, as it does not affect the cornea or cause elevated intraocular pressure.

Q: A patient with angle-closure glaucoma is posted for laser iridotomy. Which of the following lasers is used for iridotomy?

Nd:YAG laser. ***Nd:YAG laser*** - The **Nd:YAG laser** is a **photodisruptive** laser commonly used for **laser iridotomy** due to its ability to create a small opening in the iris with minimal thermal damage. - Its short pulse duration and high peak power allow for precise tissue disruption, making it effective for creating a patent **iridectomy** to relieve pupillary block in angle-closure glaucoma. *Argon laser* - The **argon laser** is a **photocoagulative** laser that works by selectively heating and destroying pigmented tissue, often used for **trabeculasty** or retinal procedures. - While it can be used for iridotomy, the Argon laser carries a higher risk of **thermal damage** and inflammation compared to the Nd:YAG laser, making Nd:YAG the preferred choice. *Helium-Neon laser* - The **Helium-Neon laser** emits red light and is primarily used for **aiming and illumination** in ophthalmic laser systems, not for therapeutic tissue destruction. - It does not possess the power or tissue interaction properties required to perform a surgical procedure like **iridotomy**. *Krypton laser* - The **Krypton laser** is a **photocoagulative** laser, primarily used for various **retinal treatments**, particularly in conditions involving subretinal neovascularization due to its deeper penetration and less scattering by hemoglobin. - It is not suitable for iridotomy as its wavelength and tissue interaction are not optimized for creating an opening in the **iris**.

Q: Which of the following is not a treatment option for glaucoma?

Vitrectomy. ***Vitrectomy*** - A **vitrectomy** is a surgical procedure to remove the **vitreous humor** from the eye, typically performed for conditions like **retinal detachment**, **diabetic retinopathy**, or **vitreous hemorrhage**, not glaucoma. - While glaucoma can sometimes coexist with these conditions, vitrectomy itself is not a direct treatment for addressing the **intraocular pressure** or **optic nerve damage** characteristic of glaucoma. *Trabeculectomy* - **Trabeculectomy** is a common surgical procedure for glaucoma that creates a new drainage pathway for **aqueous humor** to reduce **intraocular pressure**. - It involves removing a small piece of the **trabecular meshwork** and sclera to form a filtering bleb. *Trabeculotomy* - **Trabeculotomy** is a surgical procedure primarily used in **congenital glaucoma** or some forms of **open-angle glaucoma** to improve the outflow of aqueous humor. - It involves incising the **trabecular meshwork** to open up the natural drainage channels. *Viscoanulostomy* - **Viscocanalostomy** (not viscoanulostomy) is a non-penetrating glaucoma surgery that aims to reduce **intraocular pressure** by improving the outflow of **aqueous humor** through the **Schlemm's canal**. - It involves dissecting the outer wall of **Schlemm's canal** and injecting viscoelastic material to dilate the canal, without creating a full-thickness fistula.

Q: Sudden loss of vision is seen in all except which of the following?

Open angle glaucoma. ***Open angle glaucoma*** - **Open-angle glaucoma** is characterized by a **slow, progressive loss of peripheral vision** over time, often without noticeable symptoms until advanced stages. - The insidious nature of vision loss means it is rarely perceived as a sudden event, making it the exception among the listed conditions. *Central retinal artery occlusion* - This condition typically presents as **sudden, profound, painless monocular vision loss**, often described as a "curtain" coming down over the eye. - It is an **ophthalmic emergency** caused by a blockage in the central retinal artery. *Retinal detachment* - Vision loss from **retinal detachment** often occurs suddenly and can manifest as a **dark curtain or shadow** in the visual field. - Patients may also report flashes of light (photopsia) and floaters prior to the vision loss. *Vitreous hemorrhage* - A **vitreous hemorrhage** causes **sudden, painless vision loss** due to blood accumulating in the vitreous cavity, blocking light transmission to the retina. - Patients often describe symptoms like **sudden onset of many floaters**, cobwebs, or a generalized haziness in their vision.

Q: All of the following drugs are used in acute congestive glaucoma EXCEPT:

Atropine. ***Atropine*** - **Atropine** is a **muscarinic antagonist** that causes **mydriasis** (pupil dilation). - In acute congestive glaucoma, pupillary dilation can further narrow the **angle of the anterior chamber**, exacerbating the condition and increasing intraocular pressure. *Pilocarpine* - **Pilocarpine** is a **cholinergic agonist** that causes **miosis** (pupil constriction), pulling the iris away from the trabecular meshwork. - This action helps to **open the anterior chamber angle** and facilitate aqueous humor outflow, thus reducing intraocular pressure. *Acetazolamide* - **Acetazolamide** is a **carbonic anhydrase inhibitor** that reduces the production of **aqueous humor** by the ciliary body. - This leads to a decrease in intraocular pressure, making it a crucial medication in the management of acute glaucoma. *Mannitol* - **Mannitol** is an **osmotic diuretic** that creates an osmotic gradient, drawing fluid from the eye into the systemic circulation. - This effect rapidly reduces **intraocular volume** and pressure, making it useful in acute glaucoma crises.

Q: Secondary glaucoma following corneal perforation is due to:

Peripheral anterior synechiae. **Peripheral anterior synechiae** - **Peripheral anterior synechiae (PAS)** occur when the iris adheres to the trabecular meshwork after corneal perforation, blocking **aqueous outflow**. - This blockage leads to increased **intraocular pressure (IOP)**, resulting in secondary glaucoma. *Central anterior synechiae formation* - **Central anterior synechiae** involve adhesion between the iris and the central cornea, which typically causes **visual obstruction** rather than glaucoma. - While it can occur after perforation, it does not directly block the **trabecular meshwork**. *Intraocular haemorrhage* - **Intraocular haemorrhage** can cause secondary glaucoma, but it does so by physically obstructing the **trabecular meshwork** or causing inflammation, not by directly sealing off the angle. - While possible after trauma, it is not the primary mechanism of glaucoma directly attributable to perforation itself, particularly when compared to PAS. *Angle recession* - **Angle recession** is a widening of the **ciliary body band** and deepening of the anterior chamber angle due to trauma, which damages the **trabecular meshwork**. - This typically occurs with blunt trauma and can lead to glaucoma years later, but it is not the immediate cause of secondary glaucoma following a corneal perforation.

Q: Laser iridotomy is useful in

Angle closure glaucoma. ***Angle closure glaucoma*** - **Laser iridotomy** creates a small hole in the iris, allowing aqueous humor to flow directly from the posterior chamber to the anterior chamber, thus relieving **pupillary block** and re-opening the angle. - This procedure is a definitive treatment for **primary angle-closure glaucoma (PACG)** and is used prophylactically in eyes at risk of angle closure. *Neovascular glaucoma* - This type of glaucoma results from the formation of **new blood vessels** on the iris and trabecular meshwork, obstructing aqueous outflow. - While laser photocoagulation to the retina (panretinal photocoagulation) is the primary treatment, **iridotomy alone** is not effective as it does not address the underlying neovascularization. *Open angle glaucoma* - In **open-angle glaucoma**, the drainage angle is open, but there is still resistance to aqueous outflow, typically at the **trabecular meshwork**. - **Laser iridotomy** does not improve aqueous outflow through the trabecular meshwork and is therefore not indicated for this condition. *Secondary glaucoma* - **Secondary glaucoma** is a broad category where the cause of elevated intraocular pressure is known, such as inflammation, trauma, or certain medications. - While iridotomy might be rarely indicated for specific secondary angle-closure mechanisms (e.g., in uveitic glaucoma with pupillary block), it is not a general treatment for **all forms of secondary glaucoma**.

Q: Which of the following lasers is NOT used in laser trabeculoplasty?

Nd: YAG laser, 1064nm. ***Nd: YAG laser, 1064nm*** - The **1064nm wavelength Nd:YAG laser** is primarily used for procedures like **posterior capsulotomy** or **iridotomy**, where its photodisruptive effect is desired. - This wavelength is not absorbed by the pigmented cells of the trabecular meshwork, making it ineffective for **trabeculoplasty**. *Nd: YAG laser, 532nm* - The **frequency-doubled Nd:YAG laser (532nm)**, also known as a **green laser**, is effectively used in **selective laser trabeculoplasty (SLT)**. - It targets **melanin-containing cells** in the trabecular meshwork, causing selective photothermolysis without coagulating adjacent non-pigmented tissue. *Argon laser* - The **argon laser** is historically significant and is used in **argon laser trabeculoplasty (ALT)**. - It creates **thermal coagulation** of the trabecular meshwork, leading to tissue contraction and increased outflow. *Diode laser* - **Diode lasers** are used in **diode laser trabeculoplasty (DLT)**. - They also utilize a **thermal effect** on the trabecular meshwork to improve aqueous outflow.

Q: Which of the following conditions does not lead to neovascularization of the iris?

Congenital cataract. ***Congenital cataract*** - **Congenital cataract** is a clouding of the lens present at birth and typically does not lead to **retinal ischemia** or subsequent **neovascularization** of the iris. - The primary issue is obstruction of light transmission rather than a vascular derangement prompting new vessel formation. - This is the correct answer as it does NOT cause iris neovascularization. *CRVO* - **Central Retinal Vein Occlusion (CRVO)** leads to significant **retinal ischemia**, which triggers the release of **pro-angiogenic factors** like VEGF. - These factors cause **neovascularization of the iris** (rubeosis iridis) and angle, leading to **neovascular glaucoma**. *Diabetic retinopathy* - **Proliferative diabetic retinopathy** is a leading cause of **iris neovascularization** due to widespread retinal **ischemia** and subsequent release of **VEGF**. - The new vessels grow on the iris surface and into the angle, causing **neovascular glaucoma**. *Fuchs heterochromic iridocyclitis* - **Fuchs heterochromic iridocyclitis** is a chronic, low-grade **anterior uveitis** characterized by iris heterochromia and fine keratic precipitates. - The fine vessels visible on the iris are **normal iris vessels made prominent** due to **iris stromal atrophy**, NOT true pathological neovascularization (rubeosis iridis). - Unlike CRVO and diabetic retinopathy, Fuchs does **NOT** cause true iris neovascularization driven by retinal ischemia and VEGF.

Q: Which of the following is the gold standard to measure the angles of the eye?

Gonioscopy. ***Gonioscopy*** - **Gonioscopy** is the gold standard for directly visualizing the **anterior chamber angle** structures, which include the iris, ciliary body, trabecular meshwork, and Schwalbe's line. - This technique uses a special **goniolens** in conjunction with a slit lamp to assess the patency and health of the drainage angle, crucial for diagnosing and managing **glaucoma**. *Perimetry* - **Perimetry**, also known as visual field testing, measures the **extent of a person's peripheral vision** and helps detect defects in the visual field. - It does not directly visualize or measure the anatomical angles within the eye's anterior chamber. *Van Herick's grading* - **Van Herick's grading** is a non-contact technique that estimates the **depth of the anterior chamber angle** by observing the peripheral anterior chamber depth with a slit lamp. - While useful for screening, it is an indirect assessment and does not provide the detailed, direct visualization offered by gonioscopy. *Cover-uncover test* - The **cover-uncover test** is used to detect and measure the presence of a **tropia** (a manifest ocular deviation) or **phoria** (a latent ocular deviation) by observing eye movements when one eye is covered and uncovered. - This test assesses eye alignment and muscle balance, not the internal angles of the anterior chamber.

Question 1

A 60-year-old male presents with colored halos around lights. The most probable diagnosis is

Accepted Answer

Acute angle closure glaucoma

Answer

Senile immature cataract

Answer

Chronic open angle glaucoma

Answer

Bacterial conjunctivitis

Question 2

A patient with angle-closure glaucoma is posted for laser iridotomy. Which of the following lasers is used for iridotomy?

Accepted Answer

Nd:YAG laser

Answer

Helium-Neon laser

Answer

Argon laser

Answer

Krypton laser

Question 3

Which of the following is not a treatment option for glaucoma?

Accepted Answer

Vitrectomy

Answer

Trabeculectomy

Answer

Trabeculotomy

Answer

Viscocanalostomy

Question 4

Sudden loss of vision is seen in all except which of the following?

Accepted Answer

Open angle glaucoma

Answer

Central retinal artery occlusion

Answer

Retinal detachment

Answer

Vitreous hemorrhage

Question 5

All of the following drugs are used in acute congestive glaucoma EXCEPT:

Accepted Answer

Atropine

Answer

Mannitol

Answer

Pilocarpine

Answer

Acetazolamide

Question 6

Secondary glaucoma following corneal perforation is due to:

Accepted Answer

Peripheral anterior synechiae

Answer

Central anterior synechiae

Answer

Intraocular haemorrhage

Answer

Angle recession

Question 7

Laser iridotomy is useful in

Accepted Answer

Angle closure glaucoma

Answer

Neovascular glaucoma

Answer

Open angle glaucoma

Answer

Secondary glaucoma

Question 8

Which of the following lasers is NOT used in laser trabeculoplasty?

Accepted Answer

Nd: YAG laser, 1064nm

Answer

Argon laser

Answer

Diode laser

Answer

Nd: YAG laser, 532nm

Question 9

Which of the following conditions does not lead to neovascularization of the iris?

Accepted Answer

Congenital cataract

Answer

CRVO

Answer

Diabetic retinopathy

Answer

Fuch's heterochromic cyclitis

Question 10

Which of the following is the gold standard to measure the angles of the eye?

Accepted Answer

Gonioscopy

Answer

Perimetry

Answer

Van Herick's grading

Answer

Cover-uncover test

Glaucoma — MCQs

Glaucoma — MCQs

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