Ophthalmic Surgery Practice Questions

Q: What size of donor cornea is taken in keratoplasty?

8 mm. **Explanation:** In Penetrating Keratoplasty (PKP), the goal is to replace the central diseased cornea with a healthy donor graft. The standard size for a donor cornea typically ranges between **7.5 mm and 8.5 mm**, making **8 mm** the most appropriate choice among the options provided. **Why 8 mm is correct:** A graft size of 7.5–8.5 mm is considered "ideal" because it is large enough to clear the visual axis and remove most central pathology, yet small enough to remain away from the limbus. Staying away from the limbus is crucial to minimize the risk of graft rejection, as the limbus is highly vascularized and contains immune cells. **Analysis of incorrect options:** * **2 mm & 4 mm:** These sizes are far too small for optical keratoplasty. They would result in significant irregular astigmatism and would not sufficiently cover the pupillary area for functional vision. * **6 mm:** While used in rare pediatric cases or specific tectonic grafts, a 6 mm graft is generally considered too small for adults, as it leads to high postoperative astigmatism and a limited visual field. **High-Yield Clinical Pearls for NEET-PG:** * **The "Oversizing" Rule:** In standard PKP, the donor button is usually cut **0.25 mm to 0.50 mm larger** than the recipient bed (e.g., an 8.0 mm donor for a 7.5 mm bed). This ensures a watertight closure, reduces postoperative flattening, and helps prevent secondary glaucoma. * **Large Grafts (>9 mm):** These are avoided in routine cases because they are closer to the limbal vessels, significantly increasing the risk of **immunological rejection** and peripheral anterior synechiae (PAS). * **Small Grafts (<7 mm):** These are associated with high **astigmatism** and poor optical outcomes.

Q: Which gas is used in retinal tamponade?

SF6. **Explanation:** **Correct Answer: A. SF6 (Sulfur Hexafluoride)** In vitreoretinal surgery, **intraocular gases** are used as a "tamponade" to provide surface tension that holds the retina against the retinal pigment epithelium (RPE) while a chorioretinal scar forms. **SF6** is a commonly used gas because it is inert, non-toxic, and expands to roughly double its volume once injected into the eye. It remains in the vitreous cavity for approximately 10–14 days, providing sufficient time for retinal reattachment. Another frequently used gas is **C3F8 (Perfluoropropane)**, which lasts longer (up to 8 weeks). **Why the other options are incorrect:** * **B. Ethylene oxide:** This is a potent gas used primarily for **sterilization** of heat-sensitive medical equipment (e.g., plastic syringes, intraocular lenses). It is highly toxic and never injected into the eye. * **C. Nitrous oxide (N2O):** This is an **inhalational anesthetic** agent. It is actually contraindicated or must be discontinued during retinal surgery involving gas because it can diffuse into the gas bubble, causing a rapid increase in intraocular pressure (IOP). * **D. CO2:** Carbon dioxide is used in laparoscopy for insufflation but has no role in retinal tamponade as it is rapidly absorbed by the blood. **High-Yield Clinical Pearls for NEET-PG:** 1. **Expansion Ratios:** SF6 expands **2x** its volume; C3F8 expands **4x** its volume. 2. **Post-operative Positioning:** Patients must maintain a specific "prone" or "face-down" position to ensure the buoyant gas bubble presses against the retinal break. 3. **Travel Warning:** Patients with an intraocular gas bubble must **avoid air travel** or high altitudes, as the decrease in atmospheric pressure causes the gas to expand, leading to a sight-threatening spike in IOP.

Q: Which of the following is NOT true regarding vitreous wick syndrome?

Seen in phacomorphic glaucoma. **Vitreous Wick Syndrome** is a postoperative complication where a strand of vitreous prolapses through a wound dehiscence or a needle track, creating a "wick" between the inner eye and the external surface. ### Why Option D is the Correct Answer **Phacomorphic glaucoma** is a type of secondary angle-closure glaucoma caused by an intumescent (swollen), cataractous lens pushing the iris forward. It is a **pre-operative** lens-induced condition. In contrast, Vitreous Wick Syndrome is strictly a **post-operative** complication related to surgical wound integrity. Therefore, it is not associated with phacomorphic glaucoma. ### Explanation of Incorrect Options * **Option A:** It is more common in **ICCE** (Intracapsular Cataract Extraction) because the posterior capsule is entirely removed, allowing vitreous to move forward easily. It can also occur in **ECCE** or Phacoemulsification if there is a posterior capsular rupture (PCR). * **Option B:** For a "wick" to form, the vitreous must first prolapse into the **anterior chamber** and then exit through the surgical incision. * **Option C:** The vitreous strand can cause **secondary glaucoma** via two mechanisms: mechanical blockage of the trabecular meshwork or by causing chronic low-grade inflammation (uveitis) that leads to synechiae. ### Clinical Pearls for NEET-PG * **Classic Presentation:** A patient presents post-cataract surgery with a peaked/distorted pupil (pointing toward the wound) and a microscopic "wick" of vitreous at the incision site. * **Major Risk:** The most serious complication is **Endophthalmitis**, as the vitreous strand acts as a conduit for bacteria to enter the eye. * **Cystoid Macular Edema (CME):** Chronic vitreous incarceration can lead to Irvine-Gass Syndrome. * **Management:** Surgical repair involves performing an anterior vitrectomy to remove the strand and resuturing the wound to ensure it is watertight.

Q: A 60-year-old diabetic patient underwent uneventful phacoemulsification with IOL implantation. On the third postoperative day, the patient presented with pain, diminished vision, redness, watering, and a grayish-yellow pupillary reflex. Examination revealed circumcorneal congestion, 4+ aqueous cells, hypopyon in the anterior chamber, and posterior synechiae. What is the most likely diagnosis?

Postoperative endophthalmitis. ### Explanation **Correct Option: A. Postoperative endophthalmitis** The clinical presentation is a classic textbook case of **Acute Postoperative Endophthalmitis**. It typically occurs within 1–7 days after intraocular surgery (most commonly phacoemulsification). * **Key Diagnostic Features:** The presence of a **grayish-yellow pupillary reflex** (indicating vitritis/exudates), **hypopyon** (pus in the anterior chamber), and severe inflammatory signs (4+ cells, circumcorneal congestion) in a patient with sudden vision loss and pain post-surgery are pathognomonic. * **Risk Factors:** Diabetes mellitus (as seen in this patient) increases the risk due to a compromised immune response. **Why Incorrect Options are Wrong:** * **B. Postoperative glaucoma:** While it causes pain and redness, it would present with corneal edema and high intraocular pressure, not a yellow pupillary reflex or hypopyon. * **C. Postoperative keratitis:** This involves the cornea (ulcers/infiltrates). While it can cause hypopyon, the primary pathology here is intraocular (behind the cornea), indicated by the pupillary reflex. * **D. Postoperative cystitis:** This is an inflammation of the urinary bladder and is irrelevant to ophthalmic surgery. **High-Yield Clinical Pearls for NEET-PG:** * **Most common causative organism:** *Staphylococcus epidermidis* (coagulase-negative Staph). * **Most virulent/severe organism:** *Pseudomonas* or *Bacillus cereus*. * **Source of infection:** Most commonly the patient’s own conjunctival and eyelid flora. * **Management:** Immediate vitreous tap for culture and intravitreal antibiotics (Vancomycin + Ceftazidime). * **Differential Diagnosis:** TASS (Toxic Anterior Segment Syndrome) – occurs within 12–24 hours, is sterile, and responds to steroids.

Q: Which of the following is not a complication of posterior capsule rupture during cataract surgery?

Angle recession. **Explanation:** **Posterior Capsule Rupture (PCR)** is a significant intraoperative complication of cataract surgery. Understanding its sequelae is vital for NEET-PG. **Why Angle Recession is the Correct Answer:** Angle recession refers to the tearing of the ciliary body face, leading to a widening of the anterior chamber angle. This is a classic hallmark of **blunt ocular trauma**, not surgical trauma during cataract extraction. It occurs due to a sudden hydraulic force pushing the iris-lens diaphragm backward during an injury. It is unrelated to the integrity of the posterior capsule. **Analysis of Incorrect Options (Complications of PCR):** * **Retinal Detachment (RD):** PCR often leads to vitreous loss. Vitreous traction on the peripheral retina (vitreoretinal traction) significantly increases the risk of rhegmatogenous retinal detachment postoperatively. * **Macular Edema (Cystoid Macular Edema/Irvine-Gass Syndrome):** Vitreous incarceration in the surgical wound or inflammatory mediators released due to PCR can lead to fluid accumulation in the macula, causing decreased vision. * **Dislocation of Intraocular Lens (IOL):** The posterior capsule provides the primary support for a standard IOL. A rupture compromises this support, leading to early or late decentration or complete dislocation of the lens into the vitreous cavity (Nucleus/IOL drop). **High-Yield Clinical Pearls:** * **Signs of PCR:** Sudden deepening of the anterior chamber, momentary pupillary dilation, and the "tilt" of the lens nucleus. * **Management:** If PCR occurs, the priority is **Anterior Vitrectomy** to clear the wound and prevent vitreous incarceration. * **IOL Choice:** In PCR with adequate capsular support, a 3-piece IOL in the sulcus is preferred. If support is absent, an ACIOL or Scleral Fixated IOL (SFIOL) is used.

Q: Uncontrolled hypertension may cause which of the following complications in cataract surgery?

Suprachoroidal hemorrhage. **Explanation:** **Suprachoroidal Hemorrhage (SCH)** is one of the most dreaded complications of intraocular surgery. It occurs due to the rupture of the **long or short posterior ciliary arteries**, leading to the accumulation of blood in the suprachoroidal space (between the choroid and the sclera). **Why Hypertension is the Key Factor:** Uncontrolled systemic hypertension is a major risk factor because it increases intravenous and intraocular pressure. During cataract surgery, when the eye is opened (incised), there is a sudden drop in intraocular pressure (**sudden hypotony**). In hypertensive patients, this pressure gradient causes the fragile ciliary vessels to rupture. This leads to an "expulsive hemorrhage," which can push intraocular contents (iris, lens, vitreous) out of the wound. **Analysis of Incorrect Options:** * **A. Glaucoma:** While postoperative pressure spikes can occur, hypertension is not a direct primary risk factor for acute surgical glaucoma compared to factors like retained viscoelastic or pupillary block. * **B. Retinal Detachment:** Risk factors include high myopia, vitreous loss, or lattice degeneration, rather than systemic hypertension. * **C. Endophthalmitis:** This is an infectious complication caused by a breach in aseptic technique or contaminated instruments; it is unrelated to the patient’s blood pressure. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factors for SCH:** Systemic hypertension, advanced age, high myopia, glaucoma, and atherosclerotic cardiovascular disease. * **Intraoperative Signs:** Sudden shallowing of the anterior chamber, increased firmness of the globe (stony hard eye), and a dark/reddish mass visible through the pupil. * **Management:** Immediate closure of the surgical incision to tamponade the bleed. * **Prevention:** Ensure blood pressure is well-controlled (ideally <140/90 mmHg) before elective cataract surgery.

Q: Which investigation is used to predict the visual outcome after phacosurgery?

Potential Acuity Meter. **Explanation:** The primary goal of cataract surgery (phacosurgery) is to restore vision. However, if a patient has co-existing retinal or optic nerve pathology (e.g., macular degeneration or optic atrophy), removing the cataract will not result in significant visual improvement. **Potential Acuity Meter (PAM)** is a specialized diagnostic tool used to estimate the "potential" visual acuity a patient might achieve after the lens opacity is removed. It works by projecting a miniaturized Snellen eye chart via a narrow beam of light through the less dense areas (windows) of the cataract directly onto the retina. If the patient can read the chart despite the cataract, it indicates that the macular function is intact and the post-operative prognosis is good. **Analysis of Incorrect Options:** * **Pachymeter:** Used to measure **corneal thickness**. It is essential for screening glaucoma (CCT) and pre-refractive surgery (LASIK) but does not predict visual potential. * **Lensometer:** An instrument used to determine the **dioptric power** of an existing pair of spectacles or hard contact lenses. * **Topometer (Keratometer/Topography):** Used to map the **curvature of the cornea**. While vital for calculating IOL power (biometry), it does not assess retinal function or visual outcome. **Clinical Pearls for NEET-PG:** * **Laser Interferometry:** Another method to predict post-op vision by projecting interference fringes onto the retina. * **In Mature/Dense Cataracts:** When the media is too opaque for PAM, **Projection of Light (PR) and Perception of Light (PL)** are used as basic clinical indicators of retinal function. * **B-Scan Ultrasonography:** Mandatory in mature cataracts to rule out retinal detachment or posterior segment tumors before surgery.

Q: UGH syndrome is commonly due to which type of intraocular lens implantation?

Anterior chamber intraocular lens (ACIOL). **Explanation:** **UGH Syndrome** (Uveitis-Glaucoma-Hyphema) is a classic complication caused by mechanical irritation of ocular structures by an intraocular lens (IOL). **1. Why ACIOL is the Correct Answer:** UGH syndrome is most commonly associated with **Anterior Chamber IOLs (ACIOLs)**, particularly older, rigid, or poorly finished closed-loop designs. Because these lenses are placed in the anterior chamber angle, the haptics or the optic can rub against the **vascular iris** or the **ciliary body**. This chronic friction leads to: * **Uveitis:** Breakdown of the blood-aqueous barrier. * **Glaucoma:** Pigment dispersion or inflammatory debris clogging the trabecular meshwork. * **Hyphema:** Mechanical erosion of iris vessels causing bleeding. **2. Analysis of Incorrect Options:** * **B. Posterior Chamber IOL (PCIOL):** These are placed in the capsular bag, away from vascular uveal tissue. While UGH can occur if a PCIOL is "sulcus-fixated" and rubs the posterior iris, it is statistically much less common than with ACIOLs. * **C. Several fixed IOLs:** This is not a standard terminology for a specific lens type associated with this syndrome. * **D. Piggyback IOL:** This involves placing two IOLs in one eye (usually to correct refractive surprises). While interlenticular opacification is a risk, UGH is not its primary association. **3. High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Blurred vision, "white-out" (due to hyphema), and increased intraocular pressure (IOP) following cataract surgery. * **Management:** Initial treatment is medical (steroids and IOP-lowering drugs), but the **definitive treatment** is often IOL explantation or exchange. * **Modern Context:** With the advent of modern, flexible, open-loop ACIOLs, the incidence of UGH has significantly decreased, but it remains a classic exam favorite.

Question 1

Leaving the lens capsule behind in cataract surgery is advantageous because it:

Accepted Answer

Prevents cystoid macular edema

Answer

Decreases endothelial damage

Answer

Progressively improves vision

Answer

Decreased chance of retinal detachment

Question 2

What size of donor cornea is taken in keratoplasty?

Accepted Answer

8 mm

Answer

2 mm

Answer

4 mm

Answer

6 mm

Question 3

Which gas is used in retinal tamponade?

Accepted Answer

SF6

Answer

Ethylene oxide

Answer

Nitrous oxide

Answer

CO2

Question 4

Which of the following is NOT true regarding vitreous wick syndrome?

Accepted Answer

Seen in phacomorphic glaucoma

Answer

More commonly seen in ICCE or ECCE

Answer

Vitreous comes in anterior chamber

Answer

Can cause secondary glaucoma

Question 5

A 60-year-old diabetic patient underwent uneventful phacoemulsification with IOL implantation. On the third postoperative day, the patient presented with pain, diminished vision, redness, watering, and a grayish-yellow pupillary reflex. Examination revealed circumcorneal congestion, 4+ aqueous cells, hypopyon in the anterior chamber, and posterior synechiae. What is the most likely diagnosis?

Accepted Answer

Postoperative endophthalmitis

Answer

Postoperative glaucoma

Answer

Postoperative keratitis

Answer

Postoperative cystitis

Question 6

Which of the following is not a complication of posterior capsule rupture during cataract surgery?

Accepted Answer

Angle recession

Answer

Retinal detachment

Answer

Macular edema

Answer

Dislocation of intraocular lens

Question 7

Uncontrolled hypertension may cause which of the following complications in cataract surgery?

Accepted Answer

Suprachoroidal hemorrhage

Answer

Glaucoma

Answer

Retinal detachment

Answer

Endophthalmitis

Question 8

Which investigation is used to predict the visual outcome after phacosurgery?

Accepted Answer

Potential Acuity Meter

Answer

Pachymeter

Answer

Lensometer

Answer

Topometer

Question 9

UGH syndrome is commonly due to which type of intraocular lens implantation?

Accepted Answer

Anterior chamber intraocular lens (ACIOL)

Answer

Posterior chamber intraocular lens (PCIOL)

Answer

Several fixed intraocular lenses

Answer

Piggyback intraocular lens

Question 10

Which of the following is NOT an advantage of leaving the lens capsule behind after cataract surgery?

Accepted Answer

Progressively improves vision

Answer

Prevents cystoid macular edema

Answer

Decreases endothelial damage

Answer

Decreases the chance of retinal detachment

Ophthalmic Surgery — MCQs

Ophthalmic Surgery — MCQs

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