Future Trends in Refractive Surgery — MCQs
Which of the following is the optimal position for inserting an IOL during a cataract surgery?
Which of the following is NOT an approach followed in revised NPCB cataract surgeries?
In primary open-angle glaucoma, pilocarpine eye drops lower intraocular pressure primarily by acting on which of the following?
A 15-year-old girl with myopic astigmatism does not want to wear glasses. What is the best alternative for her?
All are true about phakic IOLs EXCEPT:
Which antiglaucomatous drug is known to cause spasm of accommodation?
Preferred suture for corneal graft is:
Maximum correction of myopia can be done by?
A lady wants LASIK surgery for her daughter. She asks for your opinion. All the following things are suitable for performing LASIK surgery except:
A lady wants LASIK surgery for her daughter. All the following are indications for performing LASIK surgery, except:
Future Trends in Refractive Surgery Indian Medical PG Practice Questions and MCQs
Question 1: 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 2: Which of the following is NOT an approach followed in revised NPCB cataract surgeries?
- A. Mobile surgical camps
- B. Consistent follow-up care
- C. Fixed-site surgical treatment alone (excluding camps) (Correct Answer)
- D. Standardized distribution of resources
Explanation: ***Fixed-site surgical treatment alone (excluding camps)*** - The revised **National Programme for Control of Blindness and Visual Impairment (NPCBVI)** adopts a **multi-pronged integrated approach** combining both fixed-site facilities and mobile outreach camps. - Relying **exclusively on fixed-site treatment** without mobile camps is **not the strategy** of the revised program, as this would limit access for rural and underserved populations. - The program emphasizes **both institutional capacity** (fixed sites at district hospitals and eye hospitals) **and community outreach** (mobile surgical camps) working together. *Mobile surgical camps* - **Mobile camps** are a crucial strategy in the revised NPCB to reach underserved populations in rural and remote areas. - They enhance **accessibility to care** and increase surgical coverage, particularly in areas without nearby fixed facilities. - Camps are conducted with **quality standards** and linked to fixed sites for follow-up care. *Consistent follow-up care* - **Comprehensive follow-up** is a cornerstone of the revised NPCB to ensure positive outcomes and address complications. - This includes **post-operative care protocols** at both camp and fixed-site surgeries to reduce morbidity. - Follow-up mechanisms help achieve the program's goal of **quality cataract surgery outcomes**. *Standardized distribution of resources* - The revised NPCB promotes **equitable and efficient allocation** of resources to ensure quality cataract services across regions. - This includes distribution of **equipment, consumables, trained personnel, and funding** based on need and surgical load. - Resource standardization helps maintain **quality benchmarks** across different service delivery models.
Question 3: In primary open-angle glaucoma, pilocarpine eye drops lower intraocular pressure primarily by acting on which of the following?
- A. All of the options
- B. Trabecular meshwork
- C. Ciliary epithelium
- D. Longitudinal fibres of the ciliary muscle (Correct Answer)
Explanation: ***Longitudinal fibres of the ciliary muscle***- Pilocarpine is a **muscarinic agonist** that contracts the **longitudinal fibers of the ciliary muscle** [1, 3].- This contraction pulls on the **scleral spur**, separating the **trabecular meshwork** sheets, which increases conventional **aqueous humor outflow** [2, 3].*Trabecular meshwork*- While the **trabecular meshwork** is the site where aqueous humor exits the eye, pilocarpine primarily acts on the ciliary muscle to **indirectly affect** the meshwork's outflow facility [2, 3].- Pilocarpine does not directly alter the structure or function of the trabecular meshwork cells.*Ciliary epithelium*- The **ciliary epithelium** is responsible for **aqueous humor production** [1, 2].- Pilocarpine primarily affects **outflow**, not production, through its action on the ciliary muscle [1, 2].*All of the options*- Pilocarpine does not act on **all** these structures; its primary mechanism is through the ciliary muscle to enhance outflow.- It has no direct significant effect on **ciliary epithelium** or direct action on the **trabecular meshwork** itself.
Question 4: A 15-year-old girl with myopic astigmatism does not want to wear glasses. What is the best alternative for her?
- A. LASIK
- B. Spherical Specs
- C. Contact lenses (Toric) (Correct Answer)
- D. FEMTO Lasik
Explanation: ***Contact lenses (Toric)*** - **Toric contact lenses** are specifically designed to correct **astigmatism**, along with myopia or hyperopia, by having different refractive powers in different meridians. - They offer a non-surgical alternative to glasses, addressing the patient's desire not to wear spectacles, and are generally safe and effective for teenagers. *LASIK* - **LASIK (Laser-Assisted In Situ Keratomileusis)** is a surgical procedure to correct refractive errors, but it is not typically recommended for individuals under **18-21 years of age** due to continued eye growth and refractive changes. - The patient's age of 15 makes her an unsuitable candidate for LASIK at this time. *Spherical Specs* - **Spherical spectacles** are designed to correct myopia or hyperopia but cannot adequately correct **astigmatism**, which is a significant component of this patient's refractive error. - The patient also explicitly states she does not want to wear glasses, making this option undesirable. *FEMTO Lasik* - **FEMTO LASIK** is an advanced form of LASIK that uses a femtosecond laser to create the corneal flap, offering higher precision and safety. - However, similar to traditional LASIK, it is a **refractive surgical procedure** and typically not performed on patients younger than **18 years old** due to ongoing eye development.
Question 5: All are true about phakic IOLs EXCEPT:
- A. Better quality vision (Correct Answer)
- B. Suitable for thin cornea
- C. Higher endothelial loss
- D. Reversible procedure
Explanation: ***Better quality vision*** - This is the EXCEPT answer because "better quality vision" is a **comparative claim** rather than an absolute characteristic of phakic IOLs - While phakic IOLs can provide excellent optical quality, claiming they provide "better" vision is **not universally established** compared to modern LASIK or SMILE techniques - The other options describe **objective, established characteristics** specific to phakic IOLs (suitability for thin corneas, endothelial loss risk, reversibility) - Vision quality depends on multiple factors including proper sizing, centration, and absence of complications like cataract formation or glaucoma *Suitable for thin cornea* - **TRUE** - Phakic IOLs are implantable lenses placed without removing the natural lens, making them ideal for patients with **thin corneas** who are not candidates for LASIK or PRK - They do not alter corneal tissue, avoiding issues related to corneal ectasia or instability - This is a **key indication** for phakic IOL surgery *Higher endothelial loss* - **TRUE** - Phakic IOLs, especially anterior chamber types, are associated with **chronic endothelial cell loss** due to proximity to the corneal endothelium - Posterior chamber ICLs (Implantable Collamer Lens) also cause endothelial loss, though typically less than anterior chamber IOLs - Regular **endothelial cell count monitoring** is mandatory post-implantation - This is a well-documented **complication and concern** with phakic IOLs *Reversible procedure* - **TRUE** - Phakic IOL implantation is **reversible** as the lens can be explanted if complications arise or refractive needs change - This is a **major advantage** over irreversible corneal ablative procedures like LASIK or PRK - The natural crystalline lens remains intact, preserving accommodation in young patients
Question 6: Which antiglaucomatous drug is known to cause spasm of accommodation?
- A. Timolol
- B. Pilocarpine (Correct Answer)
- C. Dorzolamide
- D. Latanoprost
Explanation: ***Pilocarpine*** - **Pilocarpine** is a **direct-acting muscarinic agonist** that contracts the **ciliary muscle**. - Contraction of the ciliary muscle leads to **accommodation spasm** and a forward movement of the **iris-lens diaphragm**, which also helps to open the **trabecular meshwork**, facilitating aqueous outflow. *Timolol* - **Timolol** is a **beta-blocker** that reduces aqueous humor production by blocking beta-adrenergic receptors on the ciliary epithelium. - It does not directly affect the **ciliary muscle** or cause accommodation spasm. *Dorazolamide* - **Dorzolamide** is a **carbonic anhydrase inhibitor** that reduces aqueous humor production. - Its mechanism of action does not involve the ciliary body's mechanical action and therefore does not cause **accommodation spasm**. *Latanoprost* - **Latanoprost** is a **prostaglandin analog** that increases uveoscleral outflow of aqueous humor. - It does not directly affect the ciliary muscle's contraction or cause **accommodation spasm**.
Question 7: Preferred suture for corneal graft is:
- A. 10-0 nylon (Correct Answer)
- B. 9-0 prolene
- C. 8-0 silk
- D. 7-0 vicryl
Explanation: ***10-0 nylon*** - **10-0 nylon** is the preferred suture material for corneal grafts due to its **monofilament structure**, which reduces the risk of infection and inflammation. - Its **fine gauge** (10-0) minimizes tissue trauma and allows for precise wound approximation, crucial for maintaining corneal clarity and astigmatism control. *9-0 prolene* - While Prolene (polypropylene) is also a monofilament suture, **9-0 Prolene** is typically thicker than 10-0 nylon and may induce more astigmatism. - It is less commonly used for corneal grafts as nylon offers superior handling and knot security for this delicate tissue. *8-0 silk* - **8-0 silk** is a braided, multifilament suture, which can harbor bacteria and lead to increased inflammation and infection risk in the avascular cornea. - It is also thicker than 10-0 nylon, making it less suitable for the precise, fine suturing required in corneal transplantation. *7-0 vicryl* - **7-0 Vicryl** (polyglactin 910) is an absorbable suture, which is generally not suitable for corneal grafts where long-term wound support is required. - The absorption process can cause inflammation and unpredictable changes in suture tension, leading to astigmatism and graft instability.
Question 8: Maximum correction of myopia can be done by?
- A. Radial keratotomy
- B. LASIK (Correct Answer)
- C. Photorefractive keratectomy
- D. Orthokeratology
Explanation: ***LASIK*** - **LASIK (Laser-Assisted In Situ Keratomileusis)** allows for significant correction of high myopia by reshaping the cornea with an excimer laser. - It involves creating a **corneal flap** and then ablating tissue underneath, offering precise and stable vision correction for a wide range of refractive errors. - Among the given corneal refractive procedures, LASIK can correct myopia up to **-10 to -12 D**. *Radial keratotomy* - **Radial keratotomy (RK)** involves making radial incisions in the cornea to flatten it, primarily used for low to moderate myopia (up to -3 to -4 D). - It has a higher risk of **unpredictable outcomes**, induced astigmatism, and glare compared to modern laser procedures. *Photorefractive keratectomy* - **Photorefractive keratectomy (PRK)** involves direct ablation of the corneal surface without creating a flap, which is suitable for moderate myopia (up to -8 to -10 D). - While effective, PRK typically has a **longer recovery period** and more post-operative pain than LASIK. *Orthokeratology* - **Orthokeratology (Ortho-K)** uses specially designed rigid contact lenses worn overnight to temporarily reshape the cornea and correct myopia. - The effect is **temporary**, requiring continuous lens wear to maintain vision correction, and is generally limited to low to moderate myopia (up to -4 to -6 D).
Question 9: A lady wants LASIK surgery for her daughter. She asks for your opinion. All the following things are suitable for performing LASIK surgery except:
- A. Myopia of 4 Diopters
- B. Age of 15 years (Correct Answer)
- C. Stable refraction for 1 year
- D. Corneal thickness of 600 microns
Explanation: ***Age of 15 years*** - LASIK surgery is generally not recommended for individuals under the age of 18 because their **refractive error** may still be changing. - Ensuring **refractive stability** is crucial for long-term success of the procedure. *Myopia of 4 Diopters* - This level of **myopia** (nearsightedness) is well within the treatable range for LASIK surgery. - LASIK can effectively correct moderate myopia for improved vision. *Stable refraction for 1 year* - **Refractive stability** for at least one year is a critical prerequisite for LASIK, indicating that the patient's prescription is no longer changing significantly. - This stability ensures that the surgical correction will be lasting and accurate. *Corneal thickness of 600 microns* - A corneal thickness of 600 microns is considered **more than adequate** for LASIK surgery, as it allows for the creation of a corneal flap and subsequent ablation without compromising corneal integrity. - The minimum required corneal thickness typically falls around 500 microns, with values above this being favorable.
Question 10: A lady wants LASIK surgery for her daughter. All the following are indications for performing LASIK surgery, except:
- A. Stable refraction for 1 year
- B. Corneal thickness of 600 microns
- C. Age of 15 years (Correct Answer)
- D. Myopia of 4 Diopters
Explanation: ***Age of 15 years*** - LASIK surgery is generally not recommended for individuals under the age of 18, as their eyes and **refractive error** are still developing and stabilizing. - Performing LASIK on a 15-year-old could lead to **regression** of the refractive correction as the eye continues to grow. *Myopia of 4 Diopters* - A **myopia** of 4 Diopters (D) falls within the treatable range for LASIK, which can effectively correct moderate degrees of nearsightedness. - This is a common indication for individuals seeking freedom from glasses or contact lenses. *Stable refraction for 1 year* - **Stable refraction** for at least one year is a crucial criterion for LASIK, ensuring that the patient's prescription is unlikely to change significantly post-surgery. - Unstable refraction could result in suboptimal visual outcomes and the need for further correction. *Corneal thickness of 600 microns* - A **corneal thickness** of 600 microns is considered well within the safe range for LASIK surgery, allowing sufficient residual stromal bed after flap creation and ablation. - Adequate corneal thickness is essential to prevent complications such as **corneal ectasia**.
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