Diseases of the Lens Practice Questions

Q: The lens contains the oldest cells in which region?

Nucleus. **Explanation:** The lens is a unique biological structure because it never sheds its old cells. Throughout life, new lens fibers are continuously produced by the mitotic division of epithelial cells at the **equator**. As these new fibers are formed, they are laid down peripherally in the **cortex**, while the older fibers are progressively compressed and pushed toward the center. **1. Why the Nucleus is Correct:** The **Nucleus** represents the central core of the lens. Since the lens grows from the outside in (centripetal growth), the fibers formed during embryonic and fetal development remain trapped in the center for the individual's entire life. Therefore, the embryonic nucleus contains the oldest cells in the human body. **2. Why the other options are Incorrect:** * **Anterior and Posterior surfaces:** These represent the subcapsular regions where the youngest, most recently formed fibers are located. * **Nucleo-cortical junction:** This is a transition zone. While older than the outer cortex, it is significantly younger than the central embryonic and fetal nuclei. **Clinical Pearls for NEET-PG:** * **Lens Protein:** The lens has the highest protein content (33%) of any organ in the body, primarily **Crystallins**. * **Metabolism:** The lens is avascular and derives its nutrition from the **aqueous humor** via anaerobic glycolysis (90%). * **Sutures:** The meeting points of lens fibers form the characteristic **Y-sutures** (Erect 'Y' anteriorly, Inverted 'Y' posteriorly). * **Hardness:** As the nucleus ages, it undergoes "nuclear sclerosis" (dehydration and compaction), which is the physiological basis for age-related nuclear cataracts.

Q: What is the treatment of choice for congenital cataract?

Cataract surgery with IOL implant. **Explanation:** The primary goal in managing congenital cataract is the prevention of **amblyopia** (lazy eye) by ensuring a clear visual axis during the critical period of visual development. **Why Option C is Correct:** The current standard of care is **Cataract surgery with Intraocular Lens (IOL) implantation**. Modern surgical techniques (Phacoaspiration + Posterior Capsulotomy + Anterior Vitrectomy) combined with IOL implantation provide the best permanent optical correction. While IOL power calculation is challenging in infants due to the rapidly growing eye, it is preferred over aphakic glasses or contact lenses for better compliance and binocularity. **Why Other Options are Incorrect:** * **Option A:** Pharmacotherapy has no role in treating a lens opacity; surgery is the only definitive treatment. * **Option B:** Goniotomy is a treatment for congenital glaucoma, not cataract. While the two can coexist (e.g., in Lowe syndrome), it is not the standard treatment for isolated cataract. * **Option D:** Pars plana lensectomy was historically common, but leaving a child **aphakic** (no IOL) leads to severe refractive errors and high risk of amblyopia due to non-compliance with heavy glasses or contact lenses. **High-Yield NEET-PG Pearls:** * **Timing:** Surgery should ideally be performed within **4–6 weeks** of birth for unilateral cataracts and **8–10 weeks** for bilateral cases to prevent stimulus-deprivation amblyopia. * **IOL Age:** Most surgeons prefer IOL implantation for children **>6 months to 1 year** of age. For infants <6 months, some still prefer aphakic contact lenses due to the high risk of postoperative inflammation and "myopic shift." * **Surgical Note:** In children, a **Primary Posterior Capsulotomy (PPC)** and **Anterior Vitrectomy** are mandatory because the posterior capsule opacifies rapidly (100% rate) if left intact.

Q: Ring of Sommering is seen in which of the following conditions?

After cataract. **Explanation:** **Soemmering’s Ring** is a specific type of **After-cataract** (Posterior Capsular Opacification). It occurs following extracapsular cataract extraction (ECCE) or ocular trauma. When the central part of the lens is removed or lost, but the peripheral subcapsular lens epithelial cells (LECs) remain, these cells proliferate and undergo fiber metamorphosis within the "capsular bag" (the space between the anterior and posterior capsule). This creates a doughnut-shaped ring of cortical matter hidden behind the iris, while the central pupillary area remains clear. **Analysis of Options:** * **A. Galactosemia:** Characterized by **"Oil droplet cataracts"** due to the accumulation of dulcitol. * **B. Dislocation of lens:** Associated with conditions like Marfan syndrome or homocystinuria; it involves zonular weakness, not specific ring-shaped opacification. * **C. Acute congestive glaucoma:** Associated with **"Glaukomflecken"** (small, grey-white subcapsular opacities) due to high intraocular pressure causing focal lens necrosis. **High-Yield Facts for NEET-PG:** * **Elschnig’s Pearls:** Another form of after-cataract where subcapsular LECs proliferate and migrate onto the posterior capsule, appearing like "clusters of grapes" or pearls. * **Treatment:** The gold standard for symptomatic after-cataract is **Nd:YAG Laser Capsulotomy**. * **Prevention:** Square-edge Intraocular Lenses (IOLs) are more effective at preventing LEC migration compared to round-edge lenses.

Q: Which of the following is NOT a cause of congenital cataract?

Marfan's syndrome. **Explanation:** The correct answer is **Marfan’s syndrome**. In the context of NEET-PG, it is crucial to distinguish between lens **opacification** (cataract) and lens **dislocation** (ectopia lentis). **1. Why Marfan’s Syndrome is the correct answer:** Marfan’s syndrome is a connective tissue disorder caused by a mutation in the **FBN1 gene** (fibrillin-1). It is the most common cause of heritable **ectopia lentis** (typically superior-temporal subluxation). While patients may develop early-onset presbyopia or secondary cataracts later in life, Marfan’s is **not** a classical cause of congenital cataract. **2. Analysis of Incorrect Options:** * **Trisomy 21 (Down Syndrome):** Frequently associated with various types of congenital cataracts (often punctate or flake-like) along with Brushfield spots and keratoconus. * **Lowe’s Syndrome (Oculocerebrorenal syndrome):** An X-linked recessive disorder characterized by aminoaciduria, mental retardation, and **100% incidence of bilateral congenital cataracts** (often discoid/microphakic). * **Stickler Syndrome:** A collagenopathy (Types II/XI) that presents with high myopia, vitreoretinal degeneration, and "sunflower" or cortical congenital cataracts. **Clinical Pearls for NEET-PG:** * **Most common metabolic cause** of congenital cataract: Galactosemia (Oil droplet cataract). * **Most common intrauterine infection** causing cataract: Rubella (Pearly white nuclear cataract). * **Ectopia Lentis Mnemonic:** Marfan’s = **Up**ward (Superior-temporal); Homocystinuria = **Down**ward (Inferior-nasal). * **Lowe’s Syndrome** is a high-yield association for "Total Cataract" and glaucoma in male infants.

Q: Rapid change of presbyopic glass is a feature of –

Open angle glaucoma. **Explanation:** The correct answer is **Open angle glaucoma (OAG)**. **Why it is correct:** In Primary Open Angle Glaucoma (POAG), there is a progressive increase in intraocular pressure (IOP) which leads to **pressure-induced weakness of the ciliary muscle**. This results in a premature or rapid loss of accommodative power. Since presbyopia is the physiological loss of accommodation, any pathological weakening of the ciliary body necessitates a frequent increase in the strength of near-vision (presbyopic) glasses. Therefore, a history of "frequent change of presbyopic glasses" is a classic early clinical symptom of POAG. **Why other options are incorrect:** * **Senile cataract:** Typically causes a "second sight" phenomenon (myopic shift) due to nuclear sclerosis, where a patient may actually stop needing presbyopic glasses for a while. It does not cause a rapid *increase* in presbyopic power. * **Retinal detachment:** Presents with sudden flashes (photopsia), floaters, or a "curtain-like" vision loss. It does not affect the accommodative apparatus or refractive error in a way that mimics presbyopia. * **Intumescent cataract:** This is a stage where the lens becomes swollen. While it can cause a myopic shift or lead to secondary angle-closure glaucoma, it is not characterized by the gradual, repetitive change in presbyopic glasses seen in chronic OAG. **Clinical Pearls for NEET-PG:** * **Triad of POAG:** Raised IOP, Optic disc cupping, and Visual field defects. * **Early symptoms of POAG:** Often asymptomatic ("Silent thief of sight"), but may present with frequent change of reading glasses or delayed dark adaptation. * **Differential Diagnosis:** Rapid change in *distal* refractive error (myopia) is seen in nuclear cataract, while rapid change in *presbyopic* error is a hallmark of POAG.

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)**. This laser operates at a wavelength of 1064 nm and works on the principle of **photodisruption**. It creates a micro-explosion in the tissue (plasma formation), which mechanically cuts or "punches" a hole in the target structure without needing pigment for absorption. **Why Nd:YAG is correct:** In modern cataract surgery, the most common late complication is **Posterior Capsular Opacification (PCO)** or "After Cataract." The Nd:YAG laser is the gold standard for performing a **Posterior Capsulotomy**, where it non-invasively cuts the opacified central part of the posterior capsule to restore vision. It is also used for **Peripheral Iridotomy** in angle-closure glaucoma. **Why other options are incorrect:** * **Argon Laser:** Works on the principle of **photocoagulation**. It requires pigment (melanin/hemoglobin) to produce heat. It is used for retinal photocoagulation (diabetic retinopathy) and trabeculoplasty, but it cannot "cut" a clear capsule. * **Dye Laser:** Primarily used in photodynamic therapy (PDT) or for vascular lesions; it is not used for capsular surgery. * **Diode Laser:** Used mainly for photocoagulation, endolaser during vitrectomy, or cyclophotocoagulation in refractory glaucoma. **High-Yield Clinical Pearls for NEET-PG:** * **Nd:YAG Laser:** Photodisruptor, Solid-state laser, 1064 nm. * **Femtosecond Laser:** Used in **FLACS** (Femtosecond Laser-Assisted Cataract Surgery) for the initial *anterior* capsulorhexis and lens fragmentation. * **Excimer Laser (193 nm):** Used in LASIK for **photoablation** (breaking molecular bonds). * **Complication of YAG Capsulotomy:** Most common is a transient rise in Intraocular Pressure (IOP); others include cystoid macular edema (CME) and retinal detachment.

Q: Which of the following is true regarding the concentration of proteins in senile cataract?

More insoluble protein, less soluble protein. In the normal human lens, proteins account for approximately 33% of its weight, the highest concentration in any body tissue. These are divided into **water-soluble proteins (Crystallins: alpha, beta, and gamma)** and **water-insoluble proteins (Albuminoids).** ### Why Option A is Correct As a senile cataract develops, the lens undergoes significant biochemical changes. The primary mechanism involves the **denaturation and aggregation** of soluble crystallins. Through processes like oxidative stress, non-enzymatic glycosylation, and proteolysis, the low-molecular-weight soluble proteins transform into high-molecular-weight **insoluble aggregates**. Consequently, in a cataractous lens, the concentration of **insoluble protein increases** while the **soluble protein decreases**. This shift disrupts lens transparency, leading to opacification. ### Why Other Options are Incorrect * **Option B:** This describes a healthy, young lens where soluble crystallins predominate to maintain transparency. * **Option C:** There is no physiological or pathological state where these proteins remain in equal concentration; the progression of cataract is characterized by a definitive shift toward insolubility. ### High-Yield Clinical Pearls for NEET-PG * **Alpha-crystallins** act as molecular chaperones, preventing the precipitation of other proteins; their depletion or dysfunction is a key factor in cataractogenesis. * **Amino Acid Changes:** There is a decrease in the levels of **Glutathione** (the main antioxidant) and **Potassium**, while **Sodium, Calcium, and hydration** (in cortical cataracts) increase. * **Nuclear vs. Cortical:** Nuclear cataracts are primarily associated with protein denaturation and pigment accumulation (urochrome), whereas cortical cataracts involve electrolyte imbalance and hydration.

Q: Polychromatic lustre is seen in which of the following conditions?

Complicated cataract. **Explanation:** **1. Why Complicated Cataract is Correct:** A complicated cataract refers to opacification of the lens secondary to intraocular diseases (e.g., chronic uveitis, high myopia, or retinal detachment). The hallmark early sign is **polychromatic lustre**, which is a characteristic **iridescent play of colors** (red, green, and blue) seen at the posterior pole of the lens. This occurs due to the accumulation of metabolic debris and inflammatory byproducts in the **posterior subcapsular region**, leading to light interference patterns. Over time, this progresses to a "bread-crumb" appearance. **2. Why the Other Options are Incorrect:** * **B. Diabetes Mellitus:** Typically presents with "Snowflake cataracts" (subcapsular opacities) in young diabetics or earlier onset of senile nuclear sclerosis in older patients. * **C. Post-radiation Cataract:** Characteristically presents as a posterior subcapsular opacity, often described as a "discoid" or "saucer-shaped" opacity, but it lacks the classic polychromatic lustre associated with intraocular inflammation. * **D. Congenital Cataract:** These present in various morphologies (e.g., Zonular/Lamellar, Blue dot, or Total) depending on the genetic or metabolic trigger, but they do not exhibit polychromatic lustre. **3. High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign of Complicated Cataract:** Polychromatic lustre at the posterior pole. * **Most common cause:** Chronic Anterior Uveitis. * **Bread-crumb appearance:** A later stage of complicated cataract. * **Snowflake cataract:** Pathognomonic for Diabetes Mellitus. * **Sunflower cataract:** Seen in Wilson’s Disease (Copper deposition). * **Oil droplet cataract:** Seen in Galactosemia. * **Christmas tree cataract:** Seen in Myotonic Dystrophy.

Q: When are spectacles advised after cataract surgery?

8 weeks. **Explanation:** The primary goal of cataract surgery is to achieve a stable refractive state. Following the procedure, the eye undergoes a period of wound healing and structural remodeling, which leads to fluctuations in corneal curvature and astigmatism. **Why 8 weeks is correct:** Post-operative refractive stability is generally achieved by **6 to 8 weeks**. During this period, the surgical incision (especially in conventional ECCE or SICS) heals sufficiently, and the "surgical induced astigmatism" (SIA) stabilizes. Prescribing spectacles before this period often results in an inaccurate prescription as the refraction is still shifting. While modern Phacoemulsification with micro-incisions allows for earlier stabilization (often by 3-4 weeks), **8 weeks** remains the standard textbook and clinical benchmark for final glass prescription to ensure the most accurate and permanent correction. **Why other options are incorrect:** * **10, 12, and 14 weeks:** While prescribing glasses at these intervals is safe, it is unnecessarily delayed. By 8 weeks, the wound is physiologically stable enough for a definitive prescription. Delaying beyond this point unnecessarily prolongs the patient's visual rehabilitation. **High-Yield Clinical Pearls for NEET-PG:** * **Refractive Stabilization:** In Phacoemulsification (valvular, sutureless), stabilization is faster (3-4 weeks) compared to SICS or ECCE (6-8 weeks). * **Aphakia:** If no IOL is implanted, the patient typically requires a high plus power lens (approx. +10D) and a +3D addition for near work. * **Pseudophakia:** Most patients receive a monofocal IOL calculated for distance; thus, they require near-vision glasses (+2.5D to +3D) starting at 6-8 weeks. * **Immediate Post-op:** Patients are usually given temporary dark glasses to protect against photophobia and trauma, but not for refractive correction.

Question 1

The lens contains the oldest cells in which region?

Accepted Answer

Nucleus

Answer

Anterior surface of the lens

Answer

Posterior surface of the lens

Answer

Nucleo-cortical junction

Question 2

What is the most common type of cataract found in newborns?

Accepted Answer

Posterior polar cataract

Answer

Zonular cataract

Answer

Morganian cataract

Answer

Anterior polar cataract

Question 3

What is the treatment of choice for congenital cataract?

Accepted Answer

Cataract surgery with IOL implant

Answer

Pharmacotherapy

Answer

Combined cataract surgery and goniotomy

Answer

Pars plana lensectomy with no IOL implant

Question 4

Ring of Sommering is seen in which of the following conditions?

Accepted Answer

After cataract

Answer

Galactosemia

Answer

Dislocation of lens

Answer

Acute congestive glaucoma

Question 5

Which of the following is NOT a cause of congenital cataract?

Accepted Answer

Marfan's syndrome

Answer

Trisomy 21

Answer

Stickler syndrome

Answer

Lowe's syndrome

Question 6

Rapid change of presbyopic glass is a feature of –

Accepted Answer

Open angle glaucoma

Answer

Senile cataract

Answer

Retinal detachment

Answer

Intumescent cataract

Question 7

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 8

Which of the following is true regarding the concentration of proteins in senile cataract?

Accepted Answer

More insoluble protein, less soluble protein

Answer

More soluble protein, less insoluble protein

Answer

Equal concentration of soluble and insoluble protein

Answer

None of the above

Question 9

Polychromatic lustre is seen in which of the following conditions?

Accepted Answer

Complicated cataract

Answer

Diabetes mellitus

Answer

Post-radiation cataract

Answer

Congenital cataract

Question 10

When are spectacles advised after cataract surgery?

Accepted Answer

8 weeks

Answer

10 weeks

Answer

12 weeks

Answer

14 weeks

Diseases of the Lens — MCQs

Diseases of the Lens — MCQs

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