Ophthalmic Surgery Practice Questions

Q: What is the wavelength of the laser used in Femto Laser assisted cataract removal?

1053 nm. **Explanation:** **Correct Option: B (1053 nm)** Femtosecond lasers used in cataract surgery (FLACS) utilize an **Infrared** wavelength, typically **1053 nm**. The underlying mechanism is **photodisruption**. The laser delivers ultra-short pulses (one quadrillionth of a second), which create micro-explosions of tissue known as laser-induced optical breakdown. This process generates expanding bubbles of gas and plasma that precisely separate tissue layers (e.g., for capsulotomy or lens fragmentation) with minimal collateral thermal damage. **Analysis of Incorrect Options:** * **A. 1064 nm:** This is the wavelength of the **Nd:YAG laser**. While also an infrared laser used for photodisruption, it operates in the nanosecond range. It is primarily used for Posterior Capsulotomy and Peripheral Iridotomy. * **C. 532 nm:** This is the wavelength of the **Frequency-doubled Nd:YAG (Green) laser**. It is used for **photocoagulation** in conditions like Diabetic Retinopathy (Pan-retinal photocoagulation). * **D. 193 nm:** This is the wavelength of the **Argon-Fluoride Excimer laser**. It is a Far-Ultraviolet laser used for **photoablation** in refractive surgeries like LASIK and PRK to reshape the cornea. **High-Yield Clinical Pearls for NEET-PG:** * **FLACS Utility:** It is used for three main steps: Clear corneal incisions, Circular Capsulotomy, and Lens fragmentation. * **Precision:** The primary advantage of Femto-laser over manual technique is the creation of a perfectly centered and sized capsulorhexis, which improves IOL stability. * **Safety:** It reduces the total "Phaco time" and energy required, thereby protecting the corneal endothelium.

Q: Which laser is used for cutting out the cataract capsule?

Nd: YAG laser. **Explanation:** The correct answer is **Nd: YAG laser** (Neodymium-doped Yttrium Aluminum Garnet). **1. Why Nd: YAG Laser is Correct:** The Nd: YAG laser (1064 nm) operates on the principle of **photodisruption**. It is a "cold" laser that creates a plasma expansion, resulting in a mechanical shockwave that cuts through ocular tissues regardless of pigmentation. In cataract surgery, it is the gold standard for **Posterior Capsulotomy** to treat Posterior Capsular Opacification (PCO) and is also used for Peripheral Iridotomy in angle-closure glaucoma. **2. Why Other Options are Incorrect:** * **Argon Laser:** Operates on the principle of **photocoagulation**. It is absorbed by pigment (melanin/hemoglobin) and produces heat. It is used for retinal photocoagulation (DR, BRVO) and trabeculoplasty, but it cannot "cut" a clear or mildly opaque capsule. * **Dye Laser:** These are tunable lasers used primarily in photodynamic therapy (PDT) or specific vascular lesions; they lack the disruptive power required for capsulotomy. * **Diode Laser:** Primarily used for photocoagulation or cyclophotocoagulation (destroying ciliary processes in refractory glaucoma). Like Argon, it relies on thermal effects rather than disruption. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Nd:YAG:** Photodisruption (Ionization/Plasma formation). * **Common Complication:** Transient rise in Intraocular Pressure (IOP) is the most common side effect post-YAG capsulotomy. Cystoid Macular Edema (CME) and Retinal Detachment are rare but serious risks. * **Femtosecond Laser:** While Nd:YAG is used *post-operatively* for the capsule, the **Femtosecond laser** is used *intra-operatively* for "Laser-Assisted Cataract Surgery" (LACS) to perform the anterior capsulorhexis. * **Excimer Laser:** Used in LASIK for **photoablation** (corneal reshaping).

Q: Which of the following is NOT true regarding suprachoroidal hemorrhage?

Self-resolving. **Suprachoroidal Hemorrhage (SCH)** is one of the most dreaded complications of intraocular surgery (like cataract or glaucoma surgery). It occurs due to the rupture of the **long or short posterior ciliary arteries**, leading to the accumulation of blood in the potential space between the choroid and the sclera. ### Why "Self-resolving" is NOT true: Suprachoroidal hemorrhage is a **surgical emergency**, not a self-limiting condition. If it occurs intraoperatively (Expulsive Hemorrhage), it requires immediate closure of the wound to prevent permanent vision loss. Post-operatively, it often requires surgical intervention (sclerotomy) to drain the blood and manage secondary complications like intractable glaucoma or retinal detachment. ### Explanation of Incorrect Options: * **Shallowing of anterior chamber:** As blood accumulates in the suprachoroidal space, it pushes the ciliary body and iris diaphragm forward, leading to a sudden shallowing of the AC. * **Expulsion of intraocular contents:** In "Expulsive Hemorrhage," the rapid increase in intraocular pressure can force the vitreous, lens, or even the retina out through the surgical incision. * **Bleeding from short posterior ciliary artery:** This is the classic pathophysiological mechanism. Sudden hypotony (low pressure) during surgery causes these vessels to rupture into the suprachoroidal space. ### High-Yield Clinical Pearls for NEET-PG: * **Risk Factors:** Systemic hypertension (most common), advanced age, glaucoma, high myopia, and aphakia. * **Intraoperative Signs:** Sudden loss of red reflex, hardening of the globe (rock hard eye), and gaping of the wound. * **Management:** Immediate suturing of the wound is the first step. Definitive drainage of the hemorrhage is typically delayed for **7–14 days** to allow for clot liquefaction. * **Prophylaxis:** Preoperative control of BP and intraocular pressure (IOP) is crucial.

Q: Which of the following are complications of cataract surgery?

Endophthalmitis, Retinal detachment, Vitreous loss. **Explanation:** Cataract surgery, while highly successful, involves intraocular maneuvers that carry specific risks. The correct answer (D) identifies three classic complications: 1. **Vitreous Loss:** An intraoperative complication occurring due to posterior capsular rupture (PCR). It increases the risk of subsequent issues like glaucoma and retinal detachment. 2. **Endophthalmitis:** The most dreaded postoperative complication. It is an acute intraocular inflammation (usually bacterial) that can lead to permanent vision loss if not treated urgently. 3. **Retinal Detachment (RD):** Pseudophakic RD is a known late complication, especially in patients with high myopia or those who experienced intraoperative vitreous loss. **Analysis of Incorrect Options:** * **Optic Neuropathy:** While Ischemic Optic Neuropathy can rarely occur post-surgery due to fluctuations in intraocular pressure, it is not considered a standard or common complication of cataract surgery compared to the others listed. * **Lagophthalmos:** This is the inability to close the eyelids completely. It is typically a complication of **eyelid surgeries** (like ptosis correction) or facial nerve palsy, not intraocular cataract surgery. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Endophthalmitis:** *Staphylococcus epidermidis* (Source: Patient's own flora). * **Toxic Anterior Segment Syndrome (TASS):** An acute sterile inflammation occurring within 12–24 hours post-surgery, often confused with endophthalmitis. * **After-cataract:** Posterior Capsular Opacification (PCO) is the **most common late complication** of cataract surgery, treated with YAG laser capsulotomy. * **Irvine-Gass Syndrome:** Cystoid macular edema (CME) occurring after cataract surgery.

Q: A patient presents with a fixed dilated pupil, iris atrophy, and secondary glaucoma following penetrating keratoplasty. What condition is this suggestive of?

Uretes Zavalia syndrome. **Explanation:** **Urrets-Zavalia Syndrome (UZS)** is a rare but classic complication characterized by a **permanently fixed, dilated pupil** associated with iris atrophy and secondary glaucoma. It most commonly occurs following **penetrating keratoplasty (PKP)** for keratoconus, though it has also been reported after Deep Anterior Lamellar Keratoplasty (DALK) and other intraocular procedures. The underlying pathophysiology is believed to be **iris ischemia**. This occurs due to a sudden rise in intraocular pressure (IOP) post-operatively (often from viscoelastic retention or pupillary block), which compresses the iris root and its vasculature against the peripheral cornea or the surgical wound, leading to sphincter muscle necrosis. **Analysis of Incorrect Options:** * **Benedict’s Syndrome:** This is a midbrain stroke syndrome (Weber’s variant) involving the 3rd nerve fascicles and the red nucleus, presenting with ipsilateral CN III palsy and contralateral tremors/ataxia. It is not an ocular surgical complication. * **Posner-Schlossman Syndrome (Glaucomatocyclitic Crisis):** Characterized by recurrent episodes of very high IOP with mild anterior uveitis and fine keratic precipitates. The pupil is typically normal or slightly sluggish, not permanently fixed/atrophic. * **Kaufmann’s Syndrome:** This is not a recognized eponym in this clinical context. (Note: Herbert Kaufman is a famous cornea specialist, but no such syndrome exists for post-PKP mydriasis). **High-Yield Clinical Pearls for NEET-PG:** * **Classic Association:** Penetrating Keratoplasty for **Keratoconus**. * **Risk Factor:** Use of strong mydriatics (like Atropine) post-operatively in the presence of high IOP. * **Clinical Features:** Fixed mydriasis, iris thinning/atrophy, and **ectropion uveae**. * **Prevention:** Ensure complete removal of viscoelastics and monitor IOP closely in the immediate post-operative period.

Q: What is the best method to prevent infection after cataract surgery?

Antibiotic administration. **Explanation:** The primary goal in preventing post-cataract surgery infection (endophthalmitis) is the reduction of microbial load on the ocular surface and the prevention of bacterial entry into the eye. **Why Antibiotic Administration is Correct:** The use of antibiotics is the most evidence-based method for preventing endophthalmitis. Specifically, the **intracameral injection of Cefuroxime** (as demonstrated by the ESCRS study) at the end of surgery significantly reduces the risk of infection. Additionally, preoperative application of **Povidone-Iodine (5%)** to the conjunctival sac is considered the "gold standard" for antisepsis, as it kills bacteria more effectively than topical antibiotics alone. **Why Other Options are Incorrect:** * **Eyebrow Shaving:** This is an outdated practice. Shaving can cause micro-abrasions on the skin, which act as a nidus for bacterial colonization and actually *increase* the risk of surgical site infections. * **Irrigation of the Surgical Site:** While irrigation (hydrodissection/aspiration) is a standard part of the surgical procedure to remove lens matter, it is not a primary prophylactic measure against infection. In fact, excessive irrigation without proper aseptic technique can theoretically introduce contaminants. **Clinical Pearls for NEET-PG:** 1. **Most common organism** causing acute post-operative endophthalmitis: *Staphylococcus epidermidis* (Coagulase-negative Staph). 2. **Most common source** of infection: The patient’s own conjunctival and eyelid flora. 3. **Prophylaxis Gold Standard:** 5% Povidone-Iodine (Betadine) in the conjunctival sac (left for 3 minutes) and 10% on the periocular skin. 4. **Intracameral Cefuroxime (1mg in 0.1ml)** is the most effective pharmacological intervention to prevent endophthalmitis post-Phacoemulsification.

Q: Following cataract surgery, a patient comes with complaints of decreased visual acuity. On examination, posterior capsular opacification is seen. What type of laser can be used to treat this condition?

Nd YAG laser. ***Nd YAG laser*** - The **Nd YAG laser** (Neodymium-doped Yttrium Aluminum Garnet) is the gold standard for treating **Posterior Capsular Opacification (PCO)**, which causes secondary visual decline after cataract extraction. - It employs **photodisruption** (a non-thermal process creating plasma) to precisely cut an opening in the opacified posterior capsule, restoring the visual axis (YAG capsulotomy). *Femto laser* - The **Femtosecond laser** is commonly used for creating the corneal flap in **LASIK** or performing certain steps (**capsulotomy**, lens fragmentation) during primary cataract surgery. - It is not typically used for the treatment of *established* PCO as the **Nd YAG** laser procedure is faster, more efficient, and specifically designed for posterior capsule cutting. *Argon fluoride* - **Argon fluoride** is the emission medium for the **Excimer laser**, which operates in the ultraviolet spectrum. - The primary application of the Excimer laser in ophthalmology is **photoablation** of corneal tissue for refractive surgery (e.g., **PRK** and **LASIK**). *Argon* - The **Argon laser** is a thermal laser used primarily for **photocoagulation** in retinal conditions, such as treating **diabetic retinopathy** or performing peripheral iridotomy. - It is unsuitable for PCO treatment because its thermal mechanism would cause unnecessary heat damage to surrounding structures, unlike the non-thermal **photodisruption** of the Nd YAG laser.

Q: The type of iridectomy shown in the image is:

Peripheral basal iridectomy. ***Peripheral basal iridectomy*** - The image clearly depicts an iris with a small, circular opening located at its **periphery**, specifically at the base near the ciliary body. - This type of opening is characteristic of a **peripheral basal iridectomy**, which creates an alternative pathway for aqueous humor flow to relieve pupillary block, often associated with angle-closure glaucoma. *Sector iridectomy* - A **sector iridectomy** involves removing a full-thickness, wedge-shaped section of the iris that extends from the pupillary margin to the iris root, creating a keyhole-shaped pupil. - The image does not show a wedge-shaped defect extending to the pupil. *Button-hole iridectomy* - A **button-hole iridectomy** is typically a small, central opening in the iris that is completely surrounded by iris tissue, often performed for optical purposes. - The image shows a peripheral opening, not a central one. *Complete iridectomy* - A **complete iridectomy** implies the removal of the entire iris, or at least a very large portion, which would result in a highly enlarged and distorted pupil. - The image shows a small, localized opening, not extensive iris removal.

Question 1

What is the wavelength of the laser used in Femto Laser assisted cataract removal?

Accepted Answer

1053 nm

Answer

1064 nm

Answer

532 nm

Answer

193 nm

Question 2

Which laser is used for cutting out the cataract capsule?

Accepted Answer

Nd: YAG laser

Answer

Argon laser

Answer

Dye laser

Answer

Diode laser

Question 3

What is the percentage of endothelial cell loss during Descemet's stripping automated endothelial keratoplasty?

Accepted Answer

30 – 40%

Answer

0 – 5%

Answer

10 – 20%

Answer

50 – 60%

Question 4

Which of the following is NOT true regarding suprachoroidal hemorrhage?

Accepted Answer

Self-resolving

Answer

Shallowing of anterior chamber

Answer

Expulsion of intraocular contents

Answer

Bleeding from short posterior ciliary artery into suprachoroidal space

Question 5

Which of the following are complications of cataract surgery?

Accepted Answer

Endophthalmitis, Retinal detachment, Vitreous loss

Answer

Endophthalmitis, Optic neuropathy, Retinal detachment, Vitreous loss

Answer

Optic neuropathy, Retinal detachment, Vitreous loss, Lagophthalmos

Answer

Endophthalmitis, Optic neuropathy, Vitreous loss, Lagophthalmos

Question 6

A patient presents with a fixed dilated pupil, iris atrophy, and secondary glaucoma following penetrating keratoplasty. What condition is this suggestive of?

Accepted Answer

Uretes Zavalia syndrome

Answer

Benedict's syndrome

Answer

Posner-Schlossman syndrome

Answer

Kaufmann's syndrome

Question 7

What is the best method to prevent infection after cataract surgery?

Accepted Answer

Antibiotic administration

Answer

Eyebrow shaving

Answer

Irrigation of the surgical site

Answer

None of the above

Question 8

Following cataract surgery, a patient comes with complaints of decreased visual acuity. On examination, posterior capsular opacification is seen. What type of laser can be used to treat this condition?

Accepted Answer

Nd YAG laser

Answer

Argon

Answer

Argon fluoride

Answer

Femto laser

Question 9

A patient presented 2 weeks after cataract surgery with decreased vision. On examination, there were anterior chamber cells and flare with hazy vitreous. What is the most likely cause and organism?

Accepted Answer

Endophthalmitis with Propionibacterium

Answer

Endophthalmitis with Staphylococcus

Answer

Sympathetic ophthalmia

Answer

Toxic anterior segment syndrome

Question 10

The type of iridectomy shown in the image is:

Accepted Answer

Peripheral basal iridectomy

Answer

Sector iridectomy

Answer

Button-hole iridectomy

Answer

Complete iridectomy

Ophthalmic Surgery — MCQs

Ophthalmic Surgery — MCQs

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