Laser Therapy in Glaucoma — MCQs
Which of the following lasers is NOT used in laser trabeculoplasty?
Which of the following is the platinum-based chemotherapeutic agent used as first-line treatment for ovarian carcinoma?
What is the most important absolute indication for ophthalmic enucleation?
For laser iridotomy which laser is used?
Most common immediate complication of traumatic iridodialysis is
Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
Laser iridotomy is done in?
Secondary glaucoma associated with angle recession is seen in:
What is the earliest change in glaucoma on perimetry?
Sudden painful loss of vision seen in
Laser Therapy in Glaucoma Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following lasers is NOT used in laser trabeculoplasty?
- A. Argon laser
- B. Diode laser
- C. Nd: YAG laser, 532nm
- D. Nd: YAG laser, 1064nm (Correct Answer)
Explanation: ***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.
Question 2: Which of the following is the platinum-based chemotherapeutic agent used as first-line treatment for ovarian carcinoma?
- A. Cyclophosphamide
- B. Methotrexate
- C. Cisplatin (Correct Answer)
- D. Dacarbazine
Explanation: ***Cisplatin*** - **Cisplatin** is a platinum-based chemotherapy drug that forms **DNA cross-links**, inhibiting DNA synthesis and leading to the death of rapidly dividing cells, making it highly effective against **ovarian carcinoma**. - It is a cornerstone of chemotherapy regimens for ovarian cancer, often used in combination with other agents such as paclitaxel. *Methotrexate* - **Methotrexate** is an **antimetabolite** that inhibits dihydrofolate reductase, thereby interfering with DNA synthesis. - While it is used in various cancers like leukemia, lymphoma, and some solid tumors (e.g., breast cancer, gestational trophoblastic disease), it is **not a primary recommended drug for ovarian carcinoma**. *Cyclophosphamide* - **Cyclophosphamide** is an **alkylating agent** that causes DNA damage, leading to cell death. - It is used in many cancers, including lymphoma, breast cancer, and some leukemias, but it is **not a first-line or primary agent for ovarian carcinoma** in contemporary treatment guidelines. *Dacarbazine* - **Dacarbazine** is an **alkylating agent** primarily used in the treatment of **malignant melanoma** and Hodgkin lymphoma. - It is **not indicated for the treatment of ovarian carcinoma**.
Question 3: What is the most important absolute indication for ophthalmic enucleation?
- A. Absolute glaucoma
- B. Intraocular retinoblastoma (Correct Answer)
- C. Mutilating ocular injury
- D. Endophthalmitis
Explanation: ***Intraocular retinoblastoma*** - **Intraocular malignancy**, particularly unilateral retinoblastoma, is the most important absolute indication for enucleation as it is life-threatening. - Enucleation is performed to prevent **metastasis** and save the patient's life, as retinoblastoma can be fatal if not treated aggressively. - Other intraocular malignancies like **choroidal melanoma** may also require enucleation. *Absolute glaucoma* - Absolute glaucoma (painful blind eye) is also an absolute indication for enucleation when the eye is blind, painful, and medical management has failed. - However, it is less critical than intraocular malignancy as it doesn't pose a life-threatening risk. - Enucleation relieves pain and prevents the risk of **sympathetic ophthalmia**, though other palliative procedures like **cyclodestructive procedures** may be tried first. *Mutilating ocular injury* - Severe ocular trauma is a relative indication, not an absolute one. Initial management focuses on **repair and salvage** of the globe. - Enucleation is considered only if there's no potential for vision recovery, severe pain, or significant risk of **sympathetic ophthalmia** in the fellow eye. - Primary enucleation after trauma is rarely performed immediately. *Endophthalmitis* - Endophthalmitis is a severe intraocular infection, but enucleation is typically a last resort after medical management fails. - Initial treatment involves **intravitreal antibiotics** and possibly **vitrectomy** to eradicate the infection. - Enucleation is only considered if the infection is uncontrolled, leading to a blind and painful eye, or if there's risk of **orbital extension** or panophthalmitis.
Question 4: For laser iridotomy which laser is used?
- A. Nd YAG laser (Correct Answer)
- B. Argon laser
- C. CO2 laser
- D. Excimer laser
Explanation: ***Nd YAG laser*** - The **Nd:YAG laser** is the **primary laser used for laser iridotomy** due to its ability to create precise perforations in the iris. - This laser operates with a **photodisruptive mechanism**, generating plasma formation that effectively creates an opening in the iris. - It is the **treatment of choice for angle-closure glaucoma** and pupillary block. *Argon laser* - The **argon laser** was historically used for iridotomy but is now less commonly the primary choice due to its thermal effect causing more inflammation and scarring. - It is sometimes used in **sequential laser iridotomy** (argon first to thin the iris, followed by Nd:YAG to perforate) in cases where the iris is very thick or heavily pigmented. - Also used for **peripheral iridoplasty** and other thermal applications. *CO2 laser* - **CO2 lasers** are primarily used for **tissue ablation** in surgical procedures, particularly on the skin, eyelid lesions, or in general surgery. - They are **not suitable** for precise intraocular procedures like iridotomy due to their infrared wavelength (10,600 nm) and poor penetration through aqueous humor. *Excimer laser* - **Excimer lasers** are primarily used in **refractive surgery** (e.g., LASIK, PRK) to reshape the cornea. - They work by **photoablation** at 193 nm wavelength, precisely removing tissue layer by layer, and are not designed for creating an opening in the iris.
Question 5: Most common immediate complication of traumatic iridodialysis is
- A. Iridoplegia
- B. Hyphema (Correct Answer)
- C. Angle recession
- D. Glaucoma
Explanation: ***Hyphema*** - **Traumatic iridodialysis** involves the tearing of the iris root from the ciliary body at its insertion, which directly damages blood vessels in this highly vascular area - This leads to bleeding into the anterior chamber, causing **hyphema** (collection of blood in anterior chamber) - **Hyphema is the most common immediate complication** of iridodialysis, occurring in the majority of cases - The blood typically settles inferiorly due to gravity, creating a visible fluid level *Iridoplegia* - **Iridoplegia** (traumatic mydriasis) refers to paralysis of the iris sphincter muscle, causing a fixed dilated pupil - While this can occur with severe iris trauma, it is less common than hyphema with iridodialysis - It results from direct damage to the sphincter pupillae muscle or its nerve supply rather than from the iris root avulsion itself *Angle recession* - **Angle recession** is a tear in the ciliary body face between longitudinal and circular muscle fibers - It is a distinct injury that may **coexist** with iridodialysis from the same blunt trauma, but one does not cause the other - Both are separate manifestations of blunt ocular trauma affecting different anatomical structures - Angle recession can lead to late-onset glaucoma in 5-10% of cases *Glaucoma* - **Glaucoma** is a potential **late complication** rather than an immediate result of iridodialysis - Large iridodialysis can cause hypotony initially; small dialysis may lead to chronic drainage angle abnormalities - Secondary glaucoma typically develops months to years after the initial injury - Hyphema is the acute, immediate manifestation directly caused by vascular disruption
Question 6: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
- A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
- B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
- C. Statements 1 and 2 are incorrect
- D. Statement 1 is incorrect
Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris
Question 7: Laser iridotomy is done in?
- A. Pigmentary glaucoma
- B. None of the options
- C. Angle closure glaucoma (Correct Answer)
- D. Open angle glaucoma
Explanation: ***Angle closure glaucoma*** - **Laser iridotomy** creates a small hole in the iris, allowing aqueous humor to flow directly from the posterior to the anterior chamber, thus relieving pupillary block and opening the angle. - This procedure is the definitive treatment to prevent further **angle closure attacks** and is also used prophylactically in eyes at risk. *Open angle glaucoma* - This condition involves an **open angle** but impaired outflow of aqueous humor through the **trabecular meshwork**. - Laser iridotomy is not indicated as it does not address the primary outflow obstruction in the trabecular meshwork. *Pigmentary glaucoma* - This is a type of **open-angle glaucoma** caused by pigment dispersion that clogs the trabecular meshwork, leading to increased intraocular pressure. - While pigment can be released from the iris, the primary issue is the **trabecular meshwork obstruction**, which is not directly resolved by iridotomy. *None of the options* - This option is incorrect because **angle closure glaucoma** is a clear indication for laser iridotomy.
Question 8: Secondary glaucoma associated with angle recession is seen in:
- A. Penetrating injury
- B. Concussion injury (Correct Answer)
- C. Chemical injury
- D. Radiation injury
Explanation: ***Concussion injury*** - **Concussion injuries** (blunt trauma) to the eye lead to shearing forces between the ciliary body and sclera, causing a tear in the ciliary body and trabecular meshwork. - This anatomical alteration, known as **angle recession**, impairs aqueous humor outflow over time, leading to secondary open-angle glaucoma. *Penetrating injury* - **Penetrating injuries** breach the globe and can cause direct damage to ocular structures, but angle recession leading to glaucoma is more characteristic of blunt trauma. - Such injuries often lead to other forms of glaucoma, like **pupillary block** or **phacolytic glaucoma**, depending on the extent of damage and inflammation. *Chemical injury* - **Chemical injuries** (e.g., acid or alkali burns) cause severe inflammation, tissue necrosis, and scarring within the anterior segment. - Glaucoma following chemical injury is typically due to **trabecular meshwork damage** from inflammation and scarring, or **peripheral anterior synechiae formation**, rather than angle recession. *Radiation injury* - **Radiation injury** to the eye is rare but can occur with radiation therapy for tumors, causing damage to vascular structures and contributing to neovascularization. - Glaucoma associated with radiation injury is usually secondary to **neovascularization** of the angle or **inflammatory processes**, not angle recession.
Question 9: What is the earliest change in glaucoma on perimetry?
- A. Complete field loss
- B. Isopter contraction + baring of blind spot (Correct Answer)
- C. Tunnel vision defect
- D. Complete vision loss
Explanation: ***Isopter contraction + baring of blind spot*** - Early glaucomatous damage often manifests as an **isopter contraction**, meaning the **visual field narrows** for a given stimulus intensity. - **Baring of the blind spot** occurs when the isopter for a small target contracts inwards, leaving the physiological blind spot exposed to targets that would normally be seen. *Complete field loss* - This is indicative of **very advanced glaucoma**, representing extensive damage to the optic nerve. - It would be preceded by numerous earlier, more subtle visual field defects. *Tunnel vision defect* - **Tunnel vision** is a severe form of visual field constriction, characteristic of **advanced glaucoma** where only the central field of vision remains. - It is not the earliest change as it implies significant peripheral field loss has already occurred. *Complete vision loss* - **Complete vision loss** in an eye signifies end-stage disease, far beyond the earliest changes seen in glaucoma. - It means there is no light perception, indicating total destruction of the optic nerve fibers.
Question 10: Sudden painful loss of vision seen in
- A. Angle closure glaucoma (Correct Answer)
- B. Endophthalmitis
- C. Acute uveitis
- D. Central retinal artery occlusion
Explanation: ***Angle closure glaucoma*** - This is the **classic presentation** of sudden, painful vision loss in ophthalmology - Characterized by **acute increase in intraocular pressure** (often >40 mmHg) causing severe eye pain, headache, nausea, and vomiting - Vision loss is rapid due to damage to the **optic nerve** and corneal edema - The pain is intense and sharp due to stretching of ocular structures - **Key distinguishing feature**: Mid-dilated fixed pupil, corneal edema, shallow anterior chamber *Endophthalmitis* - Also causes **sudden painful vision loss** and is a sight-threatening emergency - Pain is severe with rapid onset of vision loss, redness, and hypopyon - **Differentiating features**: History of recent ocular surgery, trauma, or intravitreal injection; presence of hypopyon (layered pus in anterior chamber) - While both can present similarly, endophthalmitis typically has **obvious intraocular inflammation** and relevant preceding history *Acute uveitis* - Presents with **ocular pain**, **redness**, **photophobia**, and blurred vision - Vision loss is usually **gradual**, not sudden and complete - Pain is moderate, described as dull aching rather than severe acute pain - Rarely causes sudden severe vision loss unless complicated *Central retinal artery occlusion* - Causes **sudden, painless loss of vision** - this is the key distinguishing feature - Described as "curtain coming down" or sudden blackout of vision - **Absence of pain** differentiates it from acute angle-closure glaucoma - Cherry-red spot on fundoscopy is pathognomonic
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