Diseases of the Lens — MCQs

Diseases of the Lens Indian Medical PG Practice Questions and MCQs

Question 131: Rosette shaped cataract is seen in which of the following conditions?

A. Congenital rubella
B. Blunt trauma to eye (Correct Answer)
C. Wilson's disease
D. Diabetes mellitus

Explanation: **Explanation:** **Rosette-shaped cataract** is a classic clinical sign of **blunt trauma** to the eye. When the globe is struck, the mechanical shockwave causes a concussion of the lens fibers. This leads to the separation of the lens fibers along their natural sutures, typically at the interface between the anterior cortex and the adult nucleus. The resulting opacification follows the pattern of the lens sutures, appearing as a star-shaped or flower-shaped (rosette) opacity. It can be "early" (subcapsular) or "late" (deeper in the cortex). **Analysis of Incorrect Options:** * **Congenital Rubella:** Typically presents with a **pearly white nuclear cataract** or total cataract. It is often associated with "salt and pepper" retinopathy and microphthalmos. * **Wilson’s Disease:** Characterized by a **Sunflower cataract** (due to copper deposition in the anterior capsule) and the pathognomonic **Kayser-Fleischer (KF) ring** in the cornea. * **Diabetes Mellitus:** True diabetic cataract presents as **"Snowflake opacities"** (subcapsular). It is also associated with the early onset of senile nuclear sclerosis. **High-Yield Clinical Pearls for NEET-PG:** * **Vossius Ring:** A circular ring of iris pigment on the anterior lens capsule, also a sign of blunt trauma. * **Christmas Tree Cataract:** Seen in **Myotonic Dystrophy**. * **Oil Droplet Cataract:** Seen in **Galactosemia**. * **Shield Cataract:** Seen in **Atopic Dermatitis**. * **Glass-blower’s Cataract:** Caused by **Infrared radiation**, leading to true exfoliation of the lens capsule.

Question 132: An intraocular lens is implanted in a young adult after an uneventful cataract surgery. When would you typically remove the IOL?

A. Remove after 10 years
B. Remove after presbyopia develops
C. After a secondary cataract develops
D. Never removed (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Never removed**. Modern intraocular lenses (IOLs) are designed to be **biocompatible and permanent** prosthetic devices. Once implanted into the capsular bag during cataract surgery, they are intended to remain in the eye for the remainder of the patient’s life. Unlike contact lenses or external prosthetics, IOLs do not "wear out" or expire. **Why the other options are incorrect:** * **A. Remove after 10 years:** IOL materials (such as PMMA, hydrophobic, or hydrophilic acrylic) are chemically inert and do not degrade over time. There is no "shelf-life" once implanted. * **B. Remove after presbyopia develops:** Presbyopia is the age-related loss of accommodation due to the hardening of the natural lens. Since the natural lens has already been replaced by an IOL, the patient is technically "pseudophakic." If a monofocal IOL was used, the patient will already require reading glasses; the IOL is not removed when the patient reaches the typical age for presbyopia. * **C. After a secondary cataract develops:** A "secondary cataract" is actually **Posterior Capsular Opacification (PCO)**, which is a clouding of the posterior capsule behind the IOL. This is treated with a **Nd:YAG Laser Capsulotomy**, not by removing the IOL. **High-Yield Clinical Pearls for NEET-PG:** * **Indications for IOL Removal (Explantation):** IOLs are only removed in rare complications such as persistent UGH syndrome (Uveitis-Glaucoma-Hyphama), IOL dislocation/subluxation, severe chronic endophthalmitis, or toxic anterior segment syndrome (TASS). * **Material of Choice:** Hydrophobic acrylic is currently the most popular material due to lower rates of PCO. * **Positioning:** The "In-the-bag" placement is the gold standard for stability.

Question 133: Which prominent ocular manifestation is associated with Marfan's syndrome?

A. Microcornea
B. Microspherophakia
C. Megalocornea
D. Ectopia lentis (Correct Answer)

Explanation: **Explanation:** **Ectopia lentis** (subluxation of the lens) is the hallmark ocular manifestation of Marfan’s syndrome, occurring in approximately 50–80% of patients. The underlying pathology is a mutation in the **FBN1 gene** on chromosome 15, which leads to a defect in **fibrillin-1**. Since ciliary zonules are composed primarily of fibrillin, they become weak and prone to stretching or snapping. Classically, in Marfan’s, the lens displaces **superotemporally** (upward and outward), and the zonules typically remain intact but stretched. **Analysis of Incorrect Options:** * **A. Microcornea:** This refers to a corneal diameter <10 mm. While seen in conditions like nanophthalmos or congenital rubella, it is not a characteristic feature of Marfan’s. * **B. Microspherophakia:** This is a small, spherical lens. While it causes lenticular myopia, it is the classic association for **Weill-Marchesani syndrome**, not Marfan’s. * **C. Megalocornea:** This is an enlarged corneal diameter (>13 mm). While Marfan patients may have slightly larger corneas or increased axial length (leading to myopia), megalocornea is more specifically associated with X-linked megalocornea or Down syndrome. **NEET-PG High-Yield Pearls:** * **Directionality:** Marfan’s = **Upward** (Superior); Homocystinuria = **Downward** (Inferior/Nasal). * **Zonules:** In Marfan’s, zonules are **stretched/intact**; in Homocystinuria, zonules are **absent/disintegrated** (due to cysteine deficiency). * **Accommodation:** Accommodation is often preserved in Marfan’s because the zonules are stretched but still functional, unlike in total dislocation. * **Other Ocular Features:** Flat cornea (*cornea plana*), increased axial length (myopia), and increased risk of retinal detachment.

Question 134: What is the most common type of cataract found in newborns?

A. Zonular (Correct Answer)
B. Morganian
C. Anterior Polar
D. Posterior Polar

Explanation: **Explanation:** **Zonular (Lamellar) cataract** is the most common type of congenital cataract, accounting for approximately 50% of cases. It is characterized by opacification of a specific layer (zone) of the lens fibers, typically surrounding a clear embryonic nucleus. This occurs due to a transient environmental or metabolic insult during lens development. It is usually bilateral, symmetrical, and often presents with characteristic linear opacities called **"riders"** extending from the equator. **Analysis of Incorrect Options:** * **Morganian Cataract:** This is a stage of hypermature senile cataract where the cortex liquefies, allowing the dense nucleus to sink inferiorly. It is an acquired condition of the elderly, not newborns. * **Anterior Polar Cataract:** These are small, central opacities on the anterior lens capsule. While common, they are usually stationary, unilateral, and less frequent than the zonular type. * **Posterior Polar Cataract:** These occur at the posterior pole and are often associated with persistent hyaloid artery remnants. They are clinically significant due to their proximity to the nodal point but are less common than zonular cataracts. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of congenital cataract:** Idiopathic (followed by genetic/autosomal dominant). * **Most common infection:** Rubella (presents as a "pearly white" nuclear cataract). * **Galactosemia:** Associated with "Oil droplet" cataracts. * **Diabetes Mellitus:** Associated with "Snowflake" cataracts. * **Myotonic Dystrophy:** Associated with "Christmas tree" cataracts. * **Surgery Timing:** To prevent amblyopia, surgery for dense congenital cataracts should ideally be performed within the first 4–6 weeks of life.

Question 135: Iris shadow is a sign of which of the following conditions?

A. Mature cataract
B. Hypermature cataract
C. Advanced glaucoma
D. Immature cataract (Correct Answer)

Explanation: **Explanation:** The presence of an **Iris Shadow** is a classic clinical sign used to differentiate the stages of senile cortical cataract. **Why Immature Cataract is correct:** In an **Immature Senile Cataract (ISC)**, the lens is not completely opaque. There is still a layer of clear (transparent) cortex present between the anterior lens capsule and the opaque deeper fibers. When light is thrown obliquely onto the pupil, the iris casts a shadow on the underlying opacification. Because of the intervening clear cortex, the shadow of the iris is separated from the opacity, making it visible to the examiner as a crescentic dark shadow. **Why the other options are incorrect:** * **Mature Cataract:** The entire cortex has become opaque, extending right up to the anterior capsule. Since there is no clear space between the iris and the opacity, no iris shadow is formed. * **Hypermature Cataract:** The lens becomes shrunken (morgagnian or sclerotic) due to the leakage of proteins. The capsule is thickened and the cortex is no longer clear, so no iris shadow is seen. * **Advanced Glaucoma:** This condition involves optic nerve damage and visual field loss; it does not inherently involve the lens opacification required to produce an iris shadow. **High-Yield Clinical Pearls for NEET-PG:** 1. **Iris Shadow Test:** Used to judge the depth of the anterior chamber and the maturity of the cataract. 2. **Intumescent Cataract:** A subtype of immature cataract where the lens imbibes fluid and swells, making the anterior chamber shallow; it **does** show an iris shadow. 3. **Morgagnian Cataract:** A type of hypermature cataract where the cortex liquefies and the brownish nucleus settles at the bottom (milky white appearance). 4. **Visual Acuity:** In mature cataracts, vision is reduced to "Projection of Rays" (PR) and "Perception of Light" (PL). In immature cataracts, some vision (counting fingers) usually remains.

Question 136: Which of the following is NOT an antioxidant in the lens?

A. Vitamin A (Correct Answer)
B. Vitamin B complex
C. Vitamin C
D. Vitamin D

Explanation: The lens of the eye is highly susceptible to oxidative stress, which leads to protein denaturation and cataract formation. To maintain transparency, the lens utilizes a robust antioxidant defense system. **Explanation of the Correct Answer:** **Vitamin A (Retinol)** is the correct answer because it is **not** a primary antioxidant within the lens. While Vitamin A is crucial for the visual cycle (rhodopsin synthesis in the retina) and maintaining the health of the conjunctival and corneal epithelium [1], it does not play a significant role in neutralizing free radicals within the lens fibers. Deficiency of Vitamin A primarily impacts the retina and cornea rather than the lens antioxidant status [3]. **Explanation of Incorrect Options:** * **Vitamin C (Ascorbic Acid):** This is the most abundant antioxidant in the lens. Its concentration in the aqueous humor and lens is significantly higher than in the plasma, providing a primary defense against UV-induced oxidative damage [2]. * **Vitamin E (Tocopherol):** Though not listed as an option, it often works alongside Vitamin C. * **Vitamin B Complex:** Specifically, **Riboflavin (B2)** is a vital cofactor for the enzyme *Glutathione Reductase* [3]. This enzyme is essential for regenerating reduced glutathione, the most important endogenous antioxidant in the lens. * **Vitamin D:** Recent studies have identified Vitamin D receptors in the lens, and its deficiency has been linked to an increased risk of age-related cataracts, suggesting a protective antioxidant role. **High-Yield Clinical Pearls for NEET-PG:** * **Glutathione:** The "Master Antioxidant" of the lens. It maintains lens proteins in a reduced state. * **Sorbitol Pathway:** In diabetes, glucose is converted to sorbitol by *Aldose Reductase*, leading to osmotic swelling and "Snowflake Cataracts." * **Protective Enzymes:** Superoxide dismutase (SOD), Catalase, and Glutathione peroxidase are the key enzymatic antioxidants in the lens.

Question 137: What is the most common complication of extracapsular cataract surgery?

A. Retinal detachment
B. Opacification of posterior capsule (Correct Answer)
C. Vitreous haemorrhage
D. Bullous keratopathy

Explanation: **Explanation:** **Posterior Capsule Opacification (PCO)**, also known as "After-Cataract," is the most common late complication following Extracapsular Cataract Extraction (ECCE), including modern Phacoemulsification. It occurs due to the proliferation, migration, and differentiation of residual lens epithelial cells (LECs) from the equatorial region onto the posterior capsule. Clinically, this manifests as **Elschnig’s pearls** or **Soemmering’s ring**, leading to a gradual decrease in vision. **Analysis of Incorrect Options:** * **A. Retinal Detachment:** While a serious complication, it is much less common than PCO. The risk is higher in high myopes or if there is intraoperative vitreous loss. * **C. Vitreous Haemorrhage:** This is a rare complication of cataract surgery, usually associated with trauma, iris damage, or pre-existing proliferative retinopathy. * **D. Bullous Keratopathy:** This results from corneal endothelial decompensation due to surgical trauma or high ultrasound energy. While significant, its incidence has decreased with the use of viscoelastic devices. **High-Yield Clinical Pearls for NEET-PG:** * **Treatment of PCO:** The gold standard treatment is **Nd:YAG laser capsulotomy**. * **Prevention:** Use of square-edge intraocular lenses (IOLs) and thorough cortical aspiration significantly reduces PCO rates. * **Most common early complication:** Postoperative uveitis/inflammation. * **Most dreaded complication:** Endophthalmitis (most common causative organism: *Staphylococcus epidermidis*).

Question 138: Ectopia lentis is seen in all conditions except?

A. Marfan syndrome
B. Ehlers-Danlos syndrome
C. Trauma
D. Osteogenesis imperfecta (Correct Answer)

Explanation: **Explanation:** **Ectopia lentis** refers to the displacement or malposition of the crystalline lens due to the dysfunction or disruption of the ciliary zonules. **Why Osteogenesis Imperfecta (OI) is the correct answer:** Osteogenesis imperfecta is primarily a defect in **Type I collagen**. While it is famously associated with **blue sclera** (due to thinning of the scleral collagen allowing the uvea to show through) and keratoconus, it is **not** typically associated with ectopia lentis. The zonular fibers of the lens are composed of fibrillin, not Type I collagen, which explains why the lens position remains unaffected in OI. **Analysis of incorrect options:** * **Marfan Syndrome:** The most common systemic cause of ectopia lentis. It is caused by a mutation in the **FBN1 gene** (Fibrillin-1). The displacement is classically **superotemporal** and the zonules remain intact but stretched. * **Ehlers-Danlos Syndrome:** A connective tissue disorder involving collagen mutations. While less common than in Marfan’s, ectopia lentis is a recognized ocular manifestation alongside high myopia and blue sclera. * **Trauma:** This is the **most common cause overall** of lens subluxation/dislocation. It involves the mechanical rupture of the zonular fibers. **NEET-PG High-Yield Pearls:** * **Homocystinuria:** Second most common systemic cause; displacement is typically **inferonasal**, and zonules are **brittle/disintegrated** (unlike Marfan’s). * **Weill-Marchesani Syndrome:** Associated with **microspherophakia** and downward (inferior) lens subluxation. * **Direction Mnemonic:** **M**arfan = **M**ore (Up); **H**omocystinuria = **H**eavy (Down).

Question 139: A 55-year-old patient complains of decreased distance vision. However, now he does not require his near glasses for near work. What is the most likely cause?

A. Posterior subcapsular cataract
B. Zonular cataract
C. Nuclear sclerosis (Correct Answer)
D. Anterior subcapsular cataract

Explanation: ### Explanation The correct answer is **Nuclear Sclerosis (C)**. **Why it is correct:** The clinical phenomenon described is known as **"Second Sight"** (or myopic shift). In nuclear sclerosis, the refractive index of the lens nucleus increases due to progressive compaction and hardening. This increase in refractive power shifts the eye's refraction toward **myopia**. * **Distance vision:** Decreases because the patient becomes more myopic. * **Near vision:** Improves (presbyopic correction is no longer needed) because the induced myopia compensates for the age-related loss of accommodation. **Why the other options are incorrect:** * **Posterior Subcapsular Cataract (PSC):** Typically causes significant glare and a decrease in near vision more than distance vision (due to pupillary constriction during accommodation). It does not cause a myopic shift. * **Zonular (Lamellar) Cataract:** This is the most common type of congenital cataract. It usually presents in childhood and affects specific layers of the lens fibers, not typically associated with an adult-onset myopic shift. * **Anterior Subcapsular Cataract:** Often associated with trauma or specific drugs (e.g., Amiodarone, Chlorpromazine). It does not typically result in "second sight." **High-Yield Clinical Pearls for NEET-PG:** * **Index Myopia:** Seen in Nuclear Cataract (due to increased refractive index). * **Index Hypermetropia:** Seen in Cortical Cataract (due to decreased refractive index) and Diabetes (during treatment as blood sugar drops). * **Grading:** Nuclear cataracts are graded based on color (Vogt’s classification), ranging from pale yellow (Grade I) to black (Cataracta Nigra, Grade IV) or brown (Cataracta Brunescens). * **Mnemonic:** **N**uclear = **N**ear vision improves (Second Sight).

Question 140: What are Glaucomflecken?

A. Acute uveitis associated with glaucoma
B. Lens opacities resulting from glaucoma (Correct Answer)
C. Retinal detachment occurring in glaucoma
D. Corneal opacities related to glaucoma

Explanation: **Explanation:** **Glaucomflecken** (also known as Vogt’s spots) are characteristic subcapsular lens opacities that serve as a diagnostic hallmark of a prior episode of **Acute Angle Closure Glaucoma (AACG)**. **1. Why the correct answer is right:** During an acute attack of congestive glaucoma, the intraocular pressure (IOP) rises rapidly and severely (often >60 mmHg). This extreme pressure mechanically compresses the lens epithelium against the lens capsule and compromises the microcirculation of the aqueous humor. The resulting ischemia and localized stasis of nutrients lead to **focal necrosis of the anterior lens epithelial cells**. These dead cells appear as multiple, small, grey-white, "milk-white" or "fish-scale" opacities in the subcapsular region. **2. Why the incorrect options are wrong:** * **Option A:** While uveitis can occur secondary to an acute attack (due to iris ischemia), Glaucomflecken specifically refers to lens changes, not uveal inflammation. * **Option C & D:** Glaucoma can cause corneal edema (due to endothelial pump failure) or retinal nerve fiber layer damage, but these are distinct clinical entities. Glaucomflecken is strictly a lenticular sign. **3. NEET-PG High-Yield Pearls:** * **Significance:** They are "footprints" or "silent witnesses" of a past acute pressure spike. * **Location:** Anterior subcapsular cortex, usually within the pupillary area. * **Appearance:** Small, multiple, grey-white spots. * **Differential Diagnosis:** Do not confuse with *Vossius Ring*, which is a ring of iris pigment on the anterior lens capsule following blunt trauma. * **Clinical Utility:** If you see Glaucomflecken in a quiet eye, it confirms the patient has had an undiagnosed or self-resolved attack of AACG in the past.

Practice by Chapter

Lens Anatomy and Physiology

Practice Questions

Age-Related Cataract

Practice Questions

Congenital and Developmental Cataracts

Practice Questions

Traumatic Cataract

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Metabolic Cataracts

Practice Questions

Drug-Induced Cataracts

Practice Questions

Cataract Surgery Techniques

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Intraocular Lens Implants

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Complications of Cataract Surgery

Practice Questions

Posterior Capsular Opacification

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Lens Subluxation and Dislocation

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Specialty IOLs

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