Cataract Surgery Techniques — MCQs
Which laser is used in the management of posterior capsule opacification (PCO)?
Most common method of anterior capsulotomy in phacoemulsification?
Which of the following is a true statement regarding the human eye?
Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
SAFE strategy is recommended for-
Phacoemulsification incision is at what location?
A 76-year-old female presents with difficulty reading. Bilateral white opacifications consistent with cataract formation are observed. In which structure are these opacifications located?
All are manifestation of dengue virus infection in eye except?
What is the preferred surgical technique for traumatic cataract in children?
Vision 2020 "The right to sight" includes all except-
Cataract Surgery Techniques Indian Medical PG Practice Questions and MCQs
Question 1: Which laser is used in the management of posterior capsule opacification (PCO)?
- A. Krypton
- B. Argon
- C. Excimer
- D. Nd:YAG (Correct Answer)
Explanation: ***Nd:YAG*** - The **Nd:YAG laser** is the standard treatment for posterior capsule opacification (PCO) due to its ability to create a small opening in the **opacified posterior capsule** without damaging adjacent structures. - This laser works by **photodisruption**, using short pulses of high-energy light to create plasma and mechanically break apart the capsular tissue. *Krypton* - **Krypton lasers** are primarily used in ophthalmology for **retinal photocoagulation**, particularly for conditions like diabetic retinopathy and macular edema. - They are not used for treating PCO as their mechanism is based on thermal coagulation, which would be inappropriate for the delicate posterior capsule. *Argon* - **Argon lasers** are also used for **retinal photocoagulation** and for treating conditions like **glaucoma** (e.g., argon laser trabeculoplasty). - Similar to krypton lasers, their thermal effects are not suitable for the precise, non-thermal disruption required for PCO treatment. *Excimer* - The **excimer laser** is best known for its use in **refractive surgery** like LASIK and PRK to reshape the cornea. - Its mechanism involves **photoablation**, precisely removing tissue, but it is not used for creating an opening in the posterior capsule.
Question 2: 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 3: Which of the following is a true statement regarding the human eye?
- A. Lens will not reflect light
- B. Even after cataract surgery UV rays do not penetrate
- C. Normal eye medium will permit wavelengths of 400-700 nm (Correct Answer)
- D. Cornea cuts off wavelengths up to 400 nm
Explanation: ***Normal eye medium will permit wavelength of 400- 700 nm*** - The **normal human eye** can perceive light in the **visible spectrum**, which ranges approximately from **400 nm (violet)** to **700 nm (red)**. - This range of wavelengths is efficiently transmitted through the ocular media (cornea, aqueous humor, lens, vitreous humor) to reach the retina. *Lens will not reflect light* - The human **lens** does **reflect some light**, contributing to phenomena like **glare** and internal reflections, especially if there are opacities like cataracts. - While its primary function is to transmit and refract light, it is not perfectly non-reflective. *Even after cataract surgery UV rays are not penetrated* - Modern **intraocular lenses (IOLs)** implanted during **cataract surgery** are designed to **block UV light (UVA and UVB)** to protect the retina. - However, the natural lens also blocks UV light, and before the development of UV-blocking IOLs, patients sometimes experienced increased retinal exposure to UV post-surgery. *Cornea cut off wavelength upto 400 nm* - The **cornea** primarily absorbs and blocks **UVB (280-315 nm)** and **UVC (100-280 nm)** radiation, protecting the anterior segment structures and retina from harmful short-wavelength light. - It does **not cut off wavelengths up to 400 nm**; it primarily transmits wavelengths longer than approximately 300-310 nm into the eye.
Question 4: Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
- A. A-1, B-3, C-2, D-4
- B. A-4, B-1, C-3, D-2 (Correct Answer)
- C. A-3, B-2, C-4, D-1
- D. A-2, B-4, C-1, D-3
Explanation: ***A-4, B-1, C-3, D-2*** - **Morphine** is contraindicated in **head injury** as it can increase intracranial pressure and mask neurological symptoms. - **Amiodarone** is contraindicated in patients with **QT prolongation** due to its risk of inducing more severe arrhythmias like Torsades de Pointes. - **Vigabatrin** is contraindicated during **pregnancy** due to its potential for teratogenicity and adverse effects on fetal development. - **Estrogen preparations** are contraindicated in patients with a history of **thromboembolism** due to their increased risk of blood clot formation. *A-1, B-3, C-2, D-4* - This option incorrectly matches **Morphine** with QT prolongation and **Estrogen preparations** with head injury, which are not their primary contraindications. - It also incorrectly links **Vigabatrin** with thromboembolism and **Amiodarone** with pregnancy. *A-3, B-2, C-4, D-1* - This choice incorrectly associates **Morphine** with pregnancy and **Vigabatrin** with head injury, which are not the most critical or direct contraindications. - It also misaligns **Amiodarone** with thromboembolism and **Estrogen preparations** with QT prolongation. *A-2, B-4, C-1, D-3* - This option incorrectly matches **Morphine** with thromboembolism and **Amiodarone** with head injury, which are not their most significant contraindications. - It also incorrectly links **Vigabatrin** with QT prolongation and **Estrogen preparations** with pregnancy.
Question 5: SAFE strategy is recommended for-
- A. Diabetic retinopathy
- B. Trachoma (Correct Answer)
- C. Glaucoma
- D. Cataract
Explanation: ***Trachoma*** * The **SAFE strategy (Surgery, Antibiotics, Facial Cleanliness, Environmental improvement)** is the WHO-recommended public health approach for the elimination of **trachoma**, a chronic eye infection caused by *Chlamydia trachomatis*. * This comprehensive strategy addresses both active infection and its blinding sequelae, specifically **trichiasis** (in-turned eyelashes) through surgery. *Diabetic retinopathy* * Management of diabetic retinopathy primarily involves **blood sugar control, regular ophthalmologic exams, laser photocoagulation, and anti-VEGF injections**, not the SAFE strategy. * The focus is on preventing and treating retinal damage caused by **diabetes**, which is distinct from infectious causes. *Glaucoma* * Glaucoma is characterized by **optic nerve damage** and visual field loss, usually due to elevated intraocular pressure, and is managed with **medication, laser therapy, or surgery (e.g., trabeculectomy)**. * It is a **neurodegenerative condition**, not an infectious disease, so the SAFE strategy is not applicable. *Cataract* * Cataracts involve the **clouding of the natural lens** of the eye, leading to blurred vision, and are primarily treated through **surgical removal of the cloudy lens** and implantation of an artificial intraocular lens. * This condition is age-related or can be caused by trauma or disease, but it is **not an infection** for which the SAFE strategy would be relevant.
Question 6: Phacoemulsification incision is at what location?
- A. Sclera
- B. Sclero-corneal junction
- C. Cornea (Correct Answer)
- D. None of the options
Explanation: ***Correct: Cornea*** - The standard incision for **modern phacoemulsification** is a small (2.2-2.8mm), self-sealing **clear corneal incision**. - This incision is typically placed **1-2mm anterior to the limbus** in the temporal quadrant. - **Advantages:** Quicker healing, minimal induced astigmatism, reduced bleeding, sutureless technique, and excellent visualization. - Clear corneal incisions have become the **gold standard** for phacoemulsification since the 1990s. *Incorrect: Sclero-corneal junction* - While historically used for **limbal incisions** in traditional extracapsular cataract extraction (ECCE), this location is less common for modern phacoemulsification. - **Disadvantages:** Increased risk of bleeding from limbal vessels, potentially higher induced astigmatism, and longer healing time. - Some surgeons still use limbal or near-limbal approaches, but clear corneal incisions are preferred. *Incorrect: Sclera* - A primary incision through the **sclera alone** is not standard for phacoemulsification. - Scleral incisions may be used as **secondary port incisions** for instrument access or in specific surgical situations (e.g., combined procedures). - **Disadvantages:** Increased bleeding risk, poor visualization (non-transparent tissue), and typically requires suturing. *Incorrect: None of the options* - This is incorrect as **cornea** is definitively the correct location for standard phacoemulsification incisions in modern cataract surgery.
Question 7: A 76-year-old female presents with difficulty reading. Bilateral white opacifications consistent with cataract formation are observed. In which structure are these opacifications located?
- A. Aqueous humor
- B. Cornea
- C. Lens (Correct Answer)
- D. Optic nerve
Explanation: ***Lens*** - **Cataracts** are defined by the **clouding of the natural lens** of the eye, which causes blurred vision and difficulty with activities like reading. - The condition is very common, especially among older adults, and affects the **bilateral vision** as described in the case. *Aqueous humor* - The **aqueous humor** is a clear fluid that fills the space between the cornea and the lens; it is not the structure that becomes opaque in cataracts. - Problems with aqueous humor are typically associated with glaucoma (due to increased intraocular pressure) rather than cataract formation. *Cornea* - The **cornea** is the transparent outer layer of the eye that helps focus light, but it does not develop cataracts. - Opacities in the cornea (e.g., from injuries or infections) would be described differently and produce different visual symptoms. *Optic nerve* - The **optic nerve** transmits visual information from the retina to the brain; it is a nerve, not a structure where light focuses or where cataracts develop. - Damage to the optic nerve typically leads to vision loss or blind spots, not blurred vision from opacification.
Question 8: All are manifestation of dengue virus infection in eye except?
- A. Cataract (Correct Answer)
- B. Vitreous hemorrhage
- C. Maculopathy
- D. Optic neuritis
Explanation: ***Cataract*** - **Cataracts** are primarily associated with aging, congenital factors, trauma, or long-term steroid use, not directly with acute dengue virus infection. - While dengue can cause various ocular manifestations, the formation of cataracts is a **chronic process** that does not fit the typical acute or subacute presentation of dengue-related eye complications. *Vitreous hemorrhage* - **Vitreous hemorrhage** can occur in dengue due to associated **thrombocytopenia** and coagulation abnormalities, leading to bleeding in the eye. - Severe dengue can induce systemic vasculopathy and bleeding tendencies, which may manifest as intraocular hemorrhage. *Maculopathy* - **Dengue maculopathy** is a recognized complication, often presenting as macular edema, hemorrhage, or foveolitis, leading to visual impairment. - This is thought to be due to direct viral effects, immune-mediated responses, or vasculitis affecting the retinal microvasculature. *Optic neuritis* - **Optic neuritis** following dengue infection has been reported, characterized by inflammation of the optic nerve, causing acute vision loss. - This is considered to be an **immune-mediated post-infectious complication** rather than a direct viral cytopathic effect on the nerve.
Question 9: What is the preferred surgical technique for traumatic cataract in children?
- A. Lensectomy (Correct Answer)
- B. Contact lenses
- C. Extracapsular Cataract Extraction (ECCE) + Intraocular Lens (IOL)
- D. Glasses
Explanation: ***Lensectomy (Lensectomy-Vitrectomy)*** - **Lensectomy with anterior vitrectomy** is the preferred surgical approach for traumatic cataracts in children - Traumatic cataracts often have **compromised capsular integrity** and zonular weakness, making ECCE unsuitable - The procedure removes lens material and posterior capsule, significantly reducing the **high risk of posterior capsule opacification (PCO)** in children - **Primary IOL implantation** may be performed if the child is >2 years old and capsular support is adequate; otherwise, aphakic correction with contact lenses or secondary IOL is planned - Modern technique provides better long-term visual outcomes in pediatric trauma cases *Extracapsular Cataract Extraction (ECCE) + IOL* - **ECCE is largely outdated** for pediatric traumatic cataracts due to several limitations - Traumatic cataracts frequently have **capsular damage and zonular dehiscence**, making ECCE technically difficult and risky - Children have very high rates of **posterior capsule opacification (PCO)** with retained posterior capsule, requiring multiple YAG procedures - Cannot adequately address **vitreous complications** often associated with traumatic cataracts *Contact lenses for vision correction post-surgery* - Contact lenses are a **rehabilitation option**, not a surgical technique - Used for aphakic correction when primary IOL is not implanted (very young children or inadequate capsular support) - This addresses optical correction after surgery, not the surgical approach itself *Glasses for vision correction post-surgery* - Glasses are a **rehabilitation option**, not a surgical technique - Can provide aphakic correction but result in significant magnification and poor cosmesis - Less preferred than contact lenses for aphakic children due to optical limitations
Question 10: Vision 2020 "The right to sight" includes all except-
- A. Measles induced blindness (Correct Answer)
- B. Onchocerciasis
- C. Trachoma
- D. Cataract
Explanation: ***Measles induced blindness*** - Vision 2020 primarily targets conditions that are either preventable or treatable with *cost-effective interventions* and contribute significantly to *avoidable blindness*. - While measles can cause blindness, the specific program focuses on a defined list of priority diseases for intervention, and measles-related blindness is generally addressed through broader public health initiatives (vaccination) rather than direct "right to sight" surgical or direct medical interventions for established blindness. *Onchocerciasis* - **Onchocerciasis** (river blindness) is a major focus of Vision 2020 due to its profound impact on sight, particularly in endemic areas. - It is a **preventable** and **treatable** cause of blindness through mass drug administration. *Trachoma* - **Trachoma** is recognized as one of the leading infectious causes of blindness globally and is explicitly targeted by Vision 2020 through the **SAFE strategy** (Surgery, Antibiotics, Facial cleanliness, Environmental improvement). - It is a highly **preventable** and **treatable** condition, fitting the program's objectives. *Cataract* - **Cataract** is the leading cause of blindness worldwide and is highly **treatable** through a relatively simple and cost-effective surgical procedure. - Providing cataract surgery is a cornerstone of the Vision 2020 initiative to restore sight.
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