Glaucoma Practice Questions

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

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

Accepted Answer

Vitrectomy

Answer

Trabeculectomy

Answer

Trabeculotomy

Answer

Viscocanalostomy

Question 2

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 3

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

Accepted Answer

Atropine

Answer

Mannitol

Answer

Pilocarpine

Answer

Acetazolamide

Question 4

Secondary glaucoma following corneal perforation is due to:

Accepted Answer

Peripheral anterior synechiae

Answer

Central anterior synechiae

Answer

Intraocular haemorrhage

Answer

Angle recession

Question 5

Laser iridotomy is useful in

Accepted Answer

Angle closure glaucoma

Answer

Neovascular glaucoma

Answer

Open angle glaucoma

Answer

Secondary glaucoma

Question 6

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 7

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 8

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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