Ophthalmic Surgery — MCQs

Ophthalmic Surgery Indian Medical PG Practice Questions and MCQs

Question 101: Method followed to decrease post-op infection in cataract surgery:

A. Topical antibiotics and sterile draping
B. Topical antibiotics alone
C. Topical antibiotics and sterile instruments
D. Intracameral antibiotics and betadine wash (Correct Answer)

Explanation: ***Intracameral antibiotics and betadine wash*** - **Intracameral antibiotics** (e.g., cefuroxime, moxifloxacin) directly target the anterior chamber during surgery, effectively reducing the risk of **endophthalmitis**. - A **betadine (povidone-iodine) wash** of the ocular surface preoperatively significantly reduces bacterial load, preventing introduction of microbes into the surgical field. *Topical antibiotics and sterile draping* - While **topical antibiotics** are important, they may not achieve sufficient intraocular concentrations to prevent deep infection effectively. - **Sterile draping** is essential for maintaining a sterile field but does not address potential intrinsic bacterial flora on the conjunctiva or adnexa as thoroughly as a betadine wash. *Topical antibiotics alone* - **Topical antibiotics** alone are often insufficient to prevent **intraocular infections** because they may not penetrate the eye adequately to eradicate all pathogens. - This approach lacks the comprehensive germicidal action of a **betadine wash** on the ocular surface and the direct intraocular effect of intracameral antibiotics. *Topical antibiotics and sterile instruments* - **Sterile instruments** are a fundamental and non-negotiable part of any surgical procedure to prevent infection from external sources. - However, relying solely on **topical antibiotics** and sterile instruments overlooks the importance of reducing the patient's own **periocular bacterial flora** (addressed by betadine wash) and directly treating potential intraocular contamination (addressed by intracameral antibiotics).

Question 102: Best irrigating fluid for phacoemulsification is

A. Balanced Salt Solution (BSS Plus) (Correct Answer)
B. Glycine
C. Normal saline
D. Distilled Water

Explanation: ***Balanced Salt Solution (BSS Plus)*** - **BSS Plus** is specifically formulated for intraocular use, closely mimicking the electrolyte composition of **aqueous humor**, ensuring minimal corneal edema and damage. - It contains essential ions and bicarbonate, which helps maintain the **physiological pH and osmotic balance** necessary for delicate ocular tissues. *Glycine* - **Glycine** is often used as an irrigant in urological procedures (e.g., TURP) due to its non-conductive properties, but it is **hypo-osmolar** and can cause significant corneal swelling and endothelial damage in the eye. - It is not suitable for intraocular use as it can lead to **cellular toxicity** and metabolic disturbances in ocular tissues. *Normal saline* - While it is an isotonic solution, **normal saline (0.9% NaCl)** lacks the additional electrolytes and buffers present in BSS Plus, making it less physiological for intraocular use. - Prolonged use of normal saline in the eye can lead to **corneal edema** and disruption of the delicate balance required for maintaining corneal clarity during surgery. *Distilled Water* - **Distilled water** is a highly hypotonic solution that would cause immediate and severe **corneal swelling** and endothelial cell damage due to osmotic effects. - Its use would result in irreversible damage to ocular structures and is **contraindicated** for any intraocular procedure.

Question 103: Type of laser used for capsulotomy is:

A. Nd:YAG (Correct Answer)
B. Argon
C. Ruby
D. CO2

Explanation: ***Nd:YAG*** - The **Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser** is the gold standard for performing posterior capsulotomy after cataract surgery due to its **photodisruptive** action. - Its **nanosecond pulses** create plasma and shock waves that effectively cut the opaque posterior capsule with minimal collateral tissue damage. *Argon* - **Argon lasers** are primarily used for **photocoagulation**, such as in treating diabetic retinopathy or retinal tears, due to their ability to create thermal burns. - They are not suitable for capsulotomy as their thermal effect would cause excessive damage and scarring to the surrounding ocular tissues. *Ruby* - The **Ruby laser** was one of the earliest lasers developed but is largely **obsolete** in modern ophthalmology. - It operates at a wavelength not ideal for precise tissue cutting or photodisruption required for capsulotomy. *CO2* - **CO2 lasers** are primarily used in surgery for **tissue ablation** and cutting due to their high absorption by water, leading to surface vaporization. - They are not used for capsulotomy because their wavelength would be heavily absorbed by the ocular media, causing significant damage to the cornea and lens.

Question 104: On measuring 3.5 to 4 mm posterior to the limbus in a phakic eye and plunging a 30 gauge needle perpendicular to sclera, you pass through

A. Tenon's capsule
B. Ora serrata
C. Zonules
D. Pars plana (Correct Answer)

Explanation: ***Pars plana*** - A 3.5 to 4 mm distance posterior to the limbus in a phakic eye precisely targets the **pars plana**, the safest region for intraocular injections and surgeries to avoid lens damage. - Plunging a needle perpendicular to the sclera at this specific distance allows direct access to the vitreous cavity through the **pars plana**, bypassing critical structures. *Tenon's capsule* - **Tenon's capsule** is a fibrous sheath that envelops the eyeball, and it would be the first layer pierced, but not the final structure accessed for an intraocular procedure at this depth. - While the needle would pass through Tenon's capsule, it is an **extraocular structure** and not the target for safe intraocular access when aiming 3.5-4 mm posterior to the limbus. *Ora serrata* - The **ora serrata** is the jagged anterior termination of the retina and is located approximately 6-8 mm posterior to the limbus in the superior aspect and 5-6 mm inferiorly. - A needle plunged 3.5-4 mm from the limbus would **not reach** the ora serrata and would be positioned anterior to it. *Zonules* - The **zonules of Zinn** are suspensory ligaments that hold the lens in place, originating from the ciliary body and attaching to the lens capsule. - These structures are located more anteriorly within the anterior chamber and behind the iris, and plunging a needle 3.5-4 mm posterior to the limbus would **bypass the zonules entirely**.

Question 105: Which among the following is the BEST irrigating fluid during ECCE?

A. Ringer lactate
B. Normal saline
C. Balanced salt solution
D. Balanced salt solution + glutathione (Correct Answer)

Explanation: ***Balanced salt solution + glutathione*** - **Balanced salt solution with glutathione** is considered the best irrigating fluid for ECCE because it closely mimics the **natural aqueous humor**, maintaining corneal endothelial cell health and viability during surgery. - The addition of **glutathione** provides an antioxidant effect, protecting the corneal endothelium from oxidative stress and maintaining its metabolic function during prolonged irrigation. *Ringer lactate* - While **Ringer's lactate** is a balanced electrolyte solution, it lacks the specific components and buffering capacity present in specialized ophthalmic irrigating solutions. - It does not contain **glutathione** or other agents crucial for maintaining corneal endothelial viability and function during intraocular surgery. *Normal saline* - **Normal saline (0.9% NaCl)** lacks essential ions (calcium, magnesium, potassium) and appropriate pH buffering required for intraocular use. - Its use can lead to **corneal edema** and endothelial cell damage due to ionic imbalance and the absence of protective components found in balanced salt solutions. *Balanced salt solution* - A **plain balanced salt solution (BSS)** is a significant improvement over normal saline or Ringer's lactate as it is physiologically balanced for intraocular use, containing essential electrolytes. - However, it lacks the **antioxidant properties of glutathione**, which provides superior protection to corneal endothelial cells during extended surgical procedures.

Question 106: Most common method of anterior capsulotomy in phacoemulsification?

A. Can-opener capsulotomy
B. Envelope capsulotomy
C. Capsulorhexis (Correct Answer)
D. Linear capsulotomy

Explanation: ***Capsulorhexis*** - **Capsulorhexis** creates a continuous, curvilinear opening in the anterior capsule, which is essential for stable **intraocular lens (IOL)** placement and minimizes the risk of capsular tears during phacoemulsification. - This technique allows for better centration of the IOL and reduces the incidence of **posterior capsule opacification (PCO)**. *Can-opener capsulotomy* - This method involves making multiple small tears in the anterior capsule, resulting in a **serrated edge** that is prone to radial tears. - While historically used, it carries a higher risk of complications like **capsular tears** extending to the posterior capsule. *Envelope capsulotomy* - This term is not a standard or commonly recognized method of anterior capsulotomy in modern phacoemulsification. - Modern techniques prioritize a stable and continuous anterior capsular opening. *Linear capsulotomy* - Involves creating a straight, linear incision in the anterior capsule, which is generally not preferred for phacoemulsification due to its **instability** and higher risk of extension. - This method provides less structural integrity for the remaining capsule compared to a continuous curvilinear capsulorhexis.

Question 107: A 56 year old patient presents after 3 days of cataract surgery with a history of increasing pain and diminution of vision after an initial improvement. The most likely cause would be:

A. Endophthalmitis (Correct Answer)
B. Central retinal vein occlusion
C. Posterior capsular opacification (PCO)
D. Retinal detachment

Explanation: ***Endophthalmitis*** - **Endophthalmitis** is a severe inflammation of the intraocular fluids (vitreous and aqueous humor), most commonly caused by infection following cataract surgery. - The presentation of **increasing pain** and **diminution of vision** a few days after initial improvement is a classic sign of acute post-operative endophthalmitis. *Central retinal vein occlusion* - **Central retinal vein occlusion (CRVO)** typically causes sudden, painless vision loss. - It is not commonly associated with **increasing pain** or a temporal relationship to recent cataract surgery in this manner. *Posterior capsular opacification (PCO)* - **Posterior capsular opacification (PCO)** develops weeks or months after cataract surgery, not within a few days. - It presents as gradual, painless blurring of vision without significant pain. *Retinal detachment* - **Retinal detachment** typically presents with sudden vision loss, flashes of light (photopsia), and floaters. - While it can occur after cataract surgery, it is less likely to present with **increasing pain** as the primary symptom described.

Question 108: Which of the following is the optimal position for inserting an IOL during a cataract surgery?

A. Iris clip
B. Posterior chamber (Correct Answer)
C. Any of the above
D. Anterior chamber

Explanation: **Posterior chamber** - The **posterior chamber** is the optimal position due to its proximity to the natural lens position, offering the best optical outcomes and minimizing complications. - Placing the IOL in the posterior chamber, typically within the **capsular bag**, provides excellent stability and reduces the risk of long-term issues like inflammation and glaucoma. *Iris clip* - **Iris-clip IOLs** are placed by clipping the lens to the iris, a technique primarily used when capsular support is inadequate. - While they can provide good visual acuity, they carry a higher risk of complications such as **uveitis-glaucoma-hyphema (UGH) syndrome** and endothelial cell loss compared to posterior chamber IOLs. *Anterior chamber* - **Anterior chamber IOLs** are placed in front of the iris and are generally reserved for cases where there is no adequate posterior capsular support. - They are associated with a higher incidence of complications like **corneal endothelial damage**, glaucoma, and peripheral anterior synechiae. *Any of the above* - This option is incorrect because while all mentioned positions can technically accommodate an IOL, they are not equally optimal or preferred. - The choice of IOL position depends on factors like **capsular support**, the patient's ocular health, and the surgeon's expertise, but the posterior chamber is overwhelmingly the gold standard when feasible.

Question 109: In which of the following conditions does IOL implantation after cataract surgery require the greatest caution and specialized management?

A. Fuchs' heterochromic iridocyclitis
B. Psoriatic arthritis
C. Reiter's syndrome
D. Juvenile rheumatoid arthritis (Correct Answer)

Explanation: ***Juvenile rheumatoid arthritis*** - Patients with **juvenile rheumatoid arthritis (JRA)**, particularly those with **pauciarticular JRA** and **ANA positivity**, are at high risk for developing chronic uveitis, which can lead to significant cataract formation and severe postoperative complications. - Due to the high risk of severe postoperative inflammation, glaucoma, and vision loss, IOL implantation in JRA patients requires extensive preoperative optimization of inflammation and careful intraoperative/postoperative management. *Fuchs' heterochromic iridocyclitis* - This condition presents with chronic, low-grade, **non-granulomatous anterior uveitis** and often leads to cataract formation. - While IOL implantation in these patients is generally well-tolerated, it does not pose the same high risk of severe postoperative inflammation and complications as seen in JRA-associated uveitis. *Psoriatic arthritis* - Psoriatic arthritis can be associated with acute anterior uveitis, but it typically presents as an acute, intermittent inflammation. - The risk of chronic, severe uveitis leading to complex cataract surgery and significant postoperative complications is not as consistently high or as severe as in JRA. *Reiter's syndrome* - Reiter's syndrome (now part of **reactive arthritis**) is another seronegative spondyloarthropathy that can cause acute anterior uveitis. - Similar to psoriatic arthritis, the uveitis is usually acute and self-limiting, and while ocular inflammation needs to be controlled, the risk profile for IOL implantation is not as challenging as in JRA.

Question 110: How many mm from the limbus is the safest site of intravitreal injection?

A. 4-5mm
B. 3-4mm (Correct Answer)
C. 1-2mm
D. 2-3mm

Explanation: ***3-4mm*** - This distance represents the **standard and safest site** for intravitreal injections in most clinical scenarios. - In **phakic eyes** (with natural lens), the injection is typically given at **3.5-4mm** from the limbus to avoid lens injury. - In **pseudophakic eyes** (with IOL), the injection is given at **3.5-4mm** from the limbus. - This distance ensures the needle tip enters the **vitreous cavity** without damaging the lens, ciliary body, or retina. - It provides safe access **anterior to the ora serrata** while maintaining adequate distance from anterior structures. *4-5mm* - This distance is **too posterior** and may place the injection site too close to or posterior to the **ora serrata** (which lies approximately 5.5-6mm from the limbus). - Injecting too posteriorly increases the risk of **retinal trauma**, **retinal detachment**, and **subretinal injection**. - Not the standard recommended distance in current ophthalmology practice guidelines. *1-2mm* - This distance is far too close to the **limbus** and would result in injection into the **anterior chamber** or **ciliary body** rather than the vitreous cavity. - Extremely high risk of **lens injury**, **hemorrhage from ciliary body vessels**, and **angle damage**. - Would not achieve proper **intravitreal drug delivery**. *2-3mm* - This distance is still **too anterior** in phakic eyes and carries significant risk of **crystalline lens injury** leading to iatrogenic cataract. - In pseudophakic eyes, while closer to acceptable range, 3-4mm provides better safety margin. - Higher risk of **ciliary body trauma** and **anterior chamber penetration**.

Practice by Chapter

Surgical Anatomy of Eye

Practice Questions

Asepsis and Sterilization in Eye Surgery

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Anesthesia in Ophthalmic Surgery

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Cataract Surgery Techniques

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Corneal Surgeries

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Glaucoma Surgeries

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Oculoplastic Surgeries

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Vitreoretinal Surgeries

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Strabismus Surgery

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Refractive Surgery

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Ocular Oncology Surgeries

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Management of Surgical Complications

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