Diseases of the Lens — MCQs

Diseases of the Lens Indian Medical PG Practice Questions and MCQs

Question 91: Sunflower type cataract is characteristically seen in which of the following conditions?

A. Chalcosis (Correct Answer)
B. Diabetes
C. Strübing's disease
D. Congenital syphilis

Explanation: **Explanation:** **Sunflower Cataract** (also known as *Cataracta Centralis Pulverulenta*) is a pathognomonic finding of **Chalcosis**, which refers to the intraocular deposition of copper. This occurs due to an intraocular copper-containing foreign body or as a manifestation of **Wilson’s disease** (Hepatolenticular degeneration). The characteristic appearance is caused by the deposition of copper in the anterior lens capsule and subcapsular epithelium, radiating outward in a petal-like fashion resembling a sunflower. **Analysis of Options:** * **A. Chalcosis (Correct):** Copper ions deposit in the basement membranes. In the eye, this leads to the Sunflower cataract and the **Kayser-Fleischer (KF) ring** in the Descemet’s membrane of the cornea. * **B. Diabetes:** Characterized by **"Snowflake cataracts"** (subcapsular opacities) in juvenile diabetics or early onset of senile nuclear sclerosis in adults. * **C. Strübing's disease:** This is not a standard ophthalmic term associated with specific lens pathology. It is likely a distractor. * **D. Congenital Syphilis:** Classically associated with **Interstitial Keratitis** (part of Hutchinson’s triad), not a sunflower cataract. **High-Yield Clinical Pearls for NEET-PG:** * **Wilson’s Disease:** Always look for the combination of Sunflower cataract + KF Ring + Low Serum Ceruloplasmin. * **Siderosis Bulbi:** Iron deposition leads to a **rusty brown** discoloration of the lens (not sunflower). * **Christmas Tree Cataract:** Seen in **Myotonic Dystrophy**. * **Oil Droplet Cataract:** Seen in **Galactosemia**. * **Rosette-shaped Cataract:** Most commonly seen in **Concussive Ocular Trauma**.

Question 92: In rosette-shaped cataract, the suture acts as a backbone in which stage?

A. Early-rosette cataract (Correct Answer)
B. Late-rosette cataract
C. Both early and late-rosette cataract
D. Neither early nor late-rosette cataract

Explanation: **Explanation:** Rosette-shaped cataract is a classic manifestation of **mechanical ocular trauma** (concussive injury). The formation occurs due to the accumulation of fluid in the potential spaces between the lens fibers, specifically along the lines of the sutures. 1. **Why Option A is Correct:** In **Early-rosette cataract**, the opacification occurs in the subcapsular region and involves the **lens sutures**. The fluid clefts radiate from the sutures, making the suture itself act as the "backbone" or the central axis of the rosette petals. This typically involves the posterior cortex. 2. **Why Option B is Incorrect:** In **Late-rosette cataract**, the opacification is pushed deeper into the lens (cortex/medulla) as new clear lens fibers are formed over time. During this transition, the "petals" of the rosette become separated from the sutures by clear zones. Therefore, the suture no longer acts as the backbone; instead, the lesion appears as a more defined, flower-like shape buried within the lens substance. 3. **Why Options C and D are Incorrect:** The structural relationship between the suture and the opacification is the primary differentiating factor between the two stages. It is present only in the early stage. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Blunt trauma (Concussion). * **Typical Location:** Usually found in the **posterior cortex** (due to the thinness of the posterior capsule and the impact of counter-coup forces). * **Vossius Ring:** Often associated with rosette cataracts; it is a circular ring of iris pigment on the anterior lens capsule following blunt trauma. * **Other Traumatic Cataracts:** "Sunflower cataract" is associated with **Chalcosis** (copper foreign body), not mechanical trauma.

Question 93: The cataract which liquefies at an advanced stage, causing lens material to liquefy and settle at the bottom, is called:

A. Intumescent cataract
B. Coralliform cataract
C. Morgagnian cataract (Correct Answer)
D. Cupuliform cataract

Explanation: ### Explanation **Morgagnian cataract** is a specific form of hypermature senile cataract. In this stage, the total liquefaction of the lens cortex occurs due to the breakdown of lens proteins into smaller, osmotically active particles. This causes the lens to lose water and shrink, but the dense, brownish **nucleus sinks to the bottom** of the liquefied capsular bag due to gravity. This characteristic appearance is often described as a "sunken nucleus" in a milky white cortex. **Analysis of Incorrect Options:** * **A. Intumescent cataract:** This is a stage of immature cataract where the lens imbibes water and becomes swollen (intumescent). While the lens is enlarged, the cortex is not yet liquefied, and the nucleus remains central. * **B. Coralliform cataract:** This is a rare type of **congenital** (developmental) cataract characterized by coral-shaped opacities radiating from the center of the lens. It is not related to the liquefaction seen in senile cataracts. * **C. Cupuliform cataract:** This is another name for a **posterior subcapsular cataract**. It is a saucer-shaped opacity located just in front of the posterior capsule. It is known for causing significant glare and vision loss, especially in bright light. **High-Yield Clinical Pearls for NEET-PG:** * **Complication:** If left untreated, a Morgagnian cataract can lead to **Phacolytic Glaucoma**, where liquefied lens proteins leak through the intact capsule and clog the trabecular meshwork. * **Phacomorphic Glaucoma:** This is associated with the **Intumescent stage**, where the swollen lens pushes the iris forward, causing secondary angle-closure glaucoma. * **Visual Acuity:** In Morgagnian cataracts, vision is typically reduced to "Hand Movements" or "Projection of Rays."

Question 94: Posterior subcapsular cataract is commonly associated with which of the following conditions?

A. Fuchs heterochromic cyclitis
B. Neurofibromatosis Type 2
C. Steroid therapy
D. All the above (Correct Answer)

Explanation: **Explanation:** **Posterior Subcapsular Cataract (PSC)** is a specific type of lens opacity located in the visual axis, just in front of the posterior capsule. It is highly significant in NEET-PG because it affects vision early (causing glare and difficulty reading) and is associated with specific systemic and ocular conditions. **Why "All the above" is correct:** 1. **Steroid Therapy (Option C):** This is the most common systemic cause of PSC. Both systemic and topical steroids lead to the migration of lens epithelial cells toward the posterior pole, where they enlarge to form **Wedl cells (bladder cells)**. 2. **Fuchs Heterochromic Cyclitis (Option A):** This is a chronic, low-grade uveitis. Complicated cataracts, specifically PSC, occur in about 75-90% of these patients due to altered aqueous humor dynamics and chronic inflammation. 3. **Neurofibromatosis Type 2 (Option B):** NF2 is classically associated with specific ocular findings, including **juvenile PSC** or posterior subcapsular opacities (found in ~60-80% of patients), often serving as a diagnostic clue for the condition. **Clinical Pearls for NEET-PG:** * **Symptoms:** Patients with PSC complain of **glare** (especially at night) and **near vision impairment** more than distance vision impairment (due to pupillary constriction during accommodation). * **Radiation:** PSC is also the characteristic cataract seen following exposure to **ionizing radiation** (X-rays/Gamma rays). * **Diabetes:** While "Snowflake cataract" is classic for juvenile diabetes, PSC is also frequently seen in adult diabetics. * **Morphology:** On slit-lamp examination, PSC often has a "bread-crumb" or "sandpaper" appearance.

Question 95: During cataractogenesis, lens striae appear first in which quadrant?

A. Upper nasal quadrant
B. Lower nasal quadrant (Correct Answer)
C. Upper temporal quadrant
D. Lower temporal quadrant

Explanation: ### Explanation The correct answer is **B. Lower nasal quadrant.** **Underlying Medical Concept:** In the development of **Senile Cortical Cataract**, the process begins with the hydration of lens fibers. This leads to the formation of water clefts and wedge-shaped opacities known as **cuneiform opacities** (lens striae). These opacities characteristically appear first in the **lower nasal quadrant** of the lens periphery. The anatomical reason for this specific localization is attributed to the **asymmetry of the zonular tension** and the fact that the lower nasal quadrant is often the most peripheral part of the lens, receiving relatively less protection from the iris and being subject to different metabolic stresses during early lens aging. These striae eventually extend toward the center, resembling the spokes of a wheel. **Analysis of Incorrect Options:** * **A, C, and D:** While cortical opacities eventually spread to involve the upper nasal, upper temporal, and lower temporal quadrants, they are rarely the site of primary origin. The progression typically follows a pattern where the lower nasal quadrant is involved first, followed by the lower temporal, and finally the upper quadrants. **Clinical Pearls for NEET-PG:** * **Stages of Cortical Cataract:** Lamellar separation → Incipient stage (cuneiform opacities) → Immature stage → Mature stage → Hypermature stage. * **Cuneiform vs. Cupuliform:** Cuneiform opacities are peripheral and wedge-shaped (cortical), whereas **Cupuliform opacities** are central and located in the posterior subcapsular layer. * **Visual Symptoms:** Patients with early cortical cataracts often complain of **glare** (due to light scattering by the striae) before a significant drop in visual acuity occurs. * **Morgagnian Cataract:** A form of hypermature cataract where the cortex liquefies and the nucleus sinks to the bottom of the capsular bag.

Question 96: Bilateral inferior lens subluxation is seen in:

A. Marfan syndrome
B. Homocysteinuria (Correct Answer)
C. Ocular trauma
D. None of the above

Explanation: **Explanation:** The correct answer is **Homocysteinuria**. Lens subluxation (ectopia lentis) occurs due to the weakening or destruction of the ciliary zonules. In Homocysteinuria, an autosomal recessive metabolic disorder caused by a deficiency of the enzyme cystathionine beta-synthase, there is a systemic deficiency of cysteine. This leads to brittle zonules that frequently disintegrate, resulting in a characteristic **inferonasal (downward and inward)** displacement of the lens. **Analysis of Options:** * **Homocysteinuria (Correct):** Classically presents with **inferior/inferonasal** subluxation. It is also associated with intellectual disability, a prothrombotic state (thromboembolism), and skeletal features similar to Marfan syndrome. * **Marfan Syndrome:** This is the most common cause of heritable ectopia lentis. However, the subluxation is typically **superotemporal (upward and outward)**. The zonules remain intact but are stretched. * **Ocular Trauma:** While trauma is the most common cause of *unilateral* lens subluxation, it is rarely bilateral and does not follow a specific directional pattern like genetic syndromes. **NEET-PG High-Yield Pearls:** * **Direction Mnemonic:** **M**arfan = **M**ore (Upward); **H**omocysteinuria = **H**ypo (Downward). * **Zonular Integrity:** In Marfan, zonules are stretched/elongated; in Homocysteinuria, zonules are absent or broken. * **Accommodation:** Accommodation is often preserved in Marfan syndrome because the zonules are intact, whereas it is lost in Homocysteinuria. * **Other causes of Ectopia Lentis:** Weill-Marchesani syndrome (inferior subluxation + microspherophakia), Sulfite oxidase deficiency, and Ectopia lentis et pupillae.

Question 97: Snow-flake cataract is seen in which condition?

A. Diabetes (Correct Answer)
B. Trauma
C. Chalcosis
D. Posterior subcapsular

Explanation: **Explanation:** **Snow-flake cataract** is a classic ocular manifestation of **Diabetes Mellitus**, specifically seen in young patients with uncontrolled Type 1 Diabetes (Juvenile Diabetes). **Why Diabetes is correct:** The underlying mechanism involves the **Sorbitol pathway**. In states of hyperglycemia, the enzyme *aldose reductase* converts excess glucose into sorbitol within the lens. Sorbitol is osmotic; it draws water into the lens fibers, leading to swelling and the formation of multiple white, subcapsular opacities that resemble snowflakes. While the most common cataract in diabetics is the senile cataract (occurring earlier than in non-diabetics), the "Snow-flake" appearance is the pathognomonic "true diabetic cataract." **Why other options are incorrect:** * **Trauma:** Typically presents as a **Rosette-shaped cataract** (Vossius ring may also be seen on the anterior capsule). * **Chalcosis:** Caused by intraocular copper (Wilson’s disease or foreign body), it classically results in a **Sunflower cataract**. * **Posterior Subcapsular (PSC):** This is a morphological type of cataract often associated with steroid use, ionizing radiation, or chronic intraocular inflammation (uveitis). **High-Yield Clinical Pearls for NEET-PG:** * **Galactosemia:** "Oil droplet" cataract. * **Myotonic Dystrophy:** "Christmas tree" cataract. * **Hypocalcemia:** Punctate, polychromatic luster opacities. * **Wilson’s Disease:** Sunflower cataract (Copper deposition). * **Down Syndrome:** "Snowflake" opacities can rarely occur, but "Snow-flake" is the primary keyword for Diabetes in exams.

Question 98: What is the Zonula of Zinn?

A. Primary vitreous
B. Secondary vitreous
C. Persistence of primary vitreous
D. Tertiary vitreous (Correct Answer)

Explanation: **Explanation:** The **Zonula of Zinn** (ciliary zonules) are a series of delicate fibers that connect the ciliary body to the lens capsule, holding the lens in position and enabling accommodation. **Why the correct answer is D (Tertiary Vitreous):** Embryologically, the vitreous develops in three stages: 1. **Primary Vitreous:** Formed during the 3rd to 6th week, it consists of the hyaloid artery and its branches. 2. **Secondary Vitreous:** Formed from the 6th week onwards, it is the primitive gel that surrounds the primary vitreous and eventually forms the bulk of the adult vitreous body. 3. **Tertiary Vitreous:** This refers specifically to the **ciliary zonules**. These fibers develop from the neuroepithelium of the ciliary body during the later stages of development. Therefore, the Zonula of Zinn is anatomically and embryologically classified as the tertiary vitreous. **Why other options are incorrect:** * **A & B:** Primary and secondary vitreous refer to the vascular and gel-like components of the vitreous chamber itself, not the suspensory apparatus of the lens. * **C:** Persistence of primary vitreous (PHPV) is a pathological condition where the hyaloid system fails to regress, leading to a retrolental mass and potential leukocoria. **High-Yield Clinical Pearls for NEET-PG:** * **Composition:** Zonules are composed of **Fibrillin-1**. * **Clinical Correlation:** Mutations in the Fibrillin-1 gene lead to **Marfan Syndrome**, resulting in zonular weakness and **ectopia lentis** (typically superotemporal subluxation). * **Homocystinuria:** Causes zonular disintegration (due to cysteine deficiency), leading to inferonasal subluxation. * **Accommodation:** When the ciliary muscle contracts, the zonules relax, allowing the lens to become more spherical (increased refractive power).

Question 99: A young, tall, thin male with archnodactyly has ectopia lentis in both eyes. What is the most likely diagnosis?

A. Marfan's syndrome (Correct Answer)
B. Marchesani's syndrome
C. Homocystinuria
D. Ehlers-Danlos syndrome

Explanation: ### Explanation **1. Why Marfan’s Syndrome is Correct:** The clinical triad of a **young, tall, thin male** (marfanoid habitus), **arachnodactyly** (long, spider-like fingers), and **ectopia lentis** (dislocated lens) is the classic presentation of Marfan’s Syndrome. It is an autosomal dominant disorder caused by a mutation in the **FBN1 gene** on chromosome 15, leading to defective **fibrillin-1**. In Marfan’s, the lens dislocation is typically **superotemporal** (upward and outward), and the zonules usually remain intact but stretched. **2. Why the Other Options are Incorrect:** * **Homocystinuria:** While patients also have a marfanoid habitus, the lens dislocation is typically **inferonasal** (downward and inward). Key differentiators include intellectual disability, increased risk of thromboembolism, and a positive cyanide-nitroprusside urine test. Zonules are usually broken/disintegrated. * **Weill-Marchesani Syndrome:** This is the "inverse" of Marfan’s. Patients are **short in stature** with short, stubby fingers (brachydactyly) and may have microspherophakia (small, spherical lenses). * **Ehlers-Danlos Syndrome:** This is primarily a collagen disorder characterized by joint hypermobility and skin hyperextensibility. While it can involve blue sclera or angioid streaks, ectopia lentis is rare compared to Marfan's. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of heritable ectopia lentis:** Marfan’s Syndrome. * **Direction of subluxation:** Marfan’s = **Up** (Superotemporal); Homocystinuria = **Down** (Inferonasal). * **Systemic Association:** Always screen Marfan’s patients for **Aortic Aneurysm/Dissection** (most common cause of death). * **Microspherophakia:** Strongly associated with Weill-Marchesani Syndrome; can cause pupillary block glaucoma.

Question 100: Lens dislocation can occur in all of the following conditions except:

A. Homocystinuria
B. Marfan's syndrome
C. Trauma
D. Wilson's disease (Correct Answer)

Explanation: **Explanation:** The correct answer is **Wilson’s Disease** because it is characterized by copper deposition in the eye, but it does not cause ectopia lentis (lens dislocation). The classic ocular finding in Wilson’s disease is the **Kayser-Fleischer (KF) ring** (copper deposition in Descemet’s membrane) and, occasionally, a **Sunflower cataract** (anterior subcapsular copper deposition). **Analysis of Options:** * **Homocystinuria:** This is a common cause of lens dislocation. Characteristically, the dislocation is **downward and inward** (inferonasal). It is associated with a deficiency of cystathionine beta-synthase and carries a high risk of thromboembolism. * **Marfan’s Syndrome:** This is the most common hereditary cause of ectopia lentis. The dislocation is typically **upward and outward** (superotemporal). The zonules are stretched but often remain intact. * **Trauma:** This is the **most common overall cause** of lens dislocation. Blunt trauma leads to the mechanical rupture of zonular fibers, resulting in subluxation or complete luxation of the lens. **High-Yield Clinical Pearls for NEET-PG:** 1. **Directionality Matters:** * Marfan’s = Upward (M**up**fan) * Homocystinuria = Downward (**Low**mocystinuria) 2. **Weill-Marchesani Syndrome:** Another high-yield cause where the lens is small and spherical (**Microspherophakia**) and typically dislocates **downward**. 3. **Ectopia Lentis et Pupillae:** A rare autosomal recessive condition characterized by lens dislocation and iris coloboma/pupil displacement in opposite directions. 4. **Sulfite Oxidase Deficiency:** A rare cause of lens dislocation associated with severe neurological impairment in infancy.

Practice by Chapter

Lens Anatomy and Physiology

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Age-Related Cataract

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Congenital and Developmental Cataracts

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Traumatic Cataract

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Metabolic Cataracts

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Drug-Induced Cataracts

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Cataract Surgery Techniques

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Intraocular Lens Implants

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Complications of Cataract Surgery

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Posterior Capsular Opacification

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Lens Subluxation and Dislocation

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Specialty IOLs

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