Diseases of the Lens — MCQs

Diseases of the Lens Indian Medical PG Practice Questions and MCQs

Question 41: Oil drop cataract is characteristic of which condition?

A. Diabetes
B. Chalcosis
C. Galactosemia (Correct Answer)
D. Wilson's disease

Explanation: **Explanation:** **Galactosemia** is the correct answer because the "oil drop" appearance is a pathognomonic sign of this metabolic disorder. In galactosemia (specifically due to **Galactose-1-phosphate uridyltransferase** deficiency), there is an accumulation of galactose in the lens. This galactose is converted into **dulcitol (galactitol)** by the enzyme aldose reductase. Dulcitol is osmotically active and draws water into the lens fibers, causing early refractive changes that appear as a central, translucent "oil drop" on retroillumination. If diagnosed early, this cataract is potentially reversible with a lactose-free diet. **Analysis of Incorrect Options:** * **Diabetes:** Characterized by **"Snowflake" cataracts** (subcapsular opacities). While high glucose also leads to sorbitol accumulation, the clinical morphology differs from the oil drop sign. * **Chalcosis:** Caused by intraocular copper (e.g., a foreign body). It results in a **"Sunflower" cataract** due to copper deposition in the anterior lens capsule. * **Wilson’s Disease:** While also involving copper metabolism, it is primarily associated with the **Kayser-Fleischer (KF) ring** in the cornea and occasionally a sunflower cataract, but never an oil drop cataract. **High-Yield Clinical Pearls for NEET-PG:** * **Galactosemia:** Oil drop cataract (Reversible in early stages). * **Diabetes Mellitus:** Snowflake cataract. * **Wilson’s Disease/Chalcosis:** Sunflower cataract. * **Myotonic Dystrophy:** Christmas tree cataract. * **Hypocalcemia:** Punctate subcapsular opacities. * **Atopic Dermatitis:** Shield cataract. * **Steroid use:** Posterior subcapsular cataract (PSC).

Question 42: Sunflower cataract is due to deposition of:

A. Cu (Correct Answer)
B. Zn
C. Fe
D. Ca

Explanation: **Explanation:** **Sunflower cataract (Chalcosis Lentis)** is caused by the intraocular deposition of **Copper (Cu)**. This occurs due to an intraocular copper-containing foreign body or as a manifestation of **Wilson’s disease** (hepatolenticular degeneration), where a deficiency in ceruloplasmin leads to systemic copper overload. The copper ions deposit in the **anterior lens capsule** and subcapsular epithelium, radiating outward in a petal-like pattern resembling a sunflower. **Analysis of Options:** * **A. Cu (Correct):** Copper has an affinity for basement membranes. In the eye, it deposits in the Descemet’s membrane (forming the **Kayser-Fleischer ring**) and the lens capsule (forming the **Sunflower cataract**). * **B. Zn (Zinc):** Zinc toxicity does not typically manifest as specific lens opacities or cataracts. * **C. Fe (Iron):** Iron deposition in the eye is known as **Siderosis Bulbi**. It typically causes a **rusty-brown discoloration** of the lens and "D-shaped" or anterior subcapsular cataracts, but not a sunflower pattern. * **D. Ca (Calcium):** Calcium deposition is associated with **Band-shaped Keratopathy** (in the cornea) or mature/hypermature cataracts, but it does not form a sunflower configuration. **High-Yield Clinical Pearls for NEET-PG:** * **Wilson’s Disease Triad:** Liver cirrhosis, Basal ganglia signs (tremors), and KF Ring. * **Kayser-Fleischer (KF) Ring:** Located at the level of **Descemet’s membrane**; it is the most common ocular sign of Wilson’s disease. * **Reversibility:** Unlike many other cataracts, a sunflower cataract is often reversible with systemic chelation therapy (e.g., D-penicillamine). * **Siderosis Bulbi (Iron):** Leads to heterochromia iridis (darker iris) and retinal degeneration (ERG shows extinguished a and b waves).

Question 43: What is the treatment of choice in aphakia?

A. Contact lens
B. Spectacles
C. Intraocular lens (IOL) (Correct Answer)
D. Laser therapy

Explanation: **Explanation:** **Aphakia** refers to the absence of the crystalline lens from the eye, most commonly following cataract surgery. The primary goal of treatment is to restore the refractive power of the eye (approximately +23D). **Why Intraocular Lens (IOL) is the Correct Answer:** IOL implantation is the **treatment of choice** because it provides the most physiological correction. It offers the best quality of vision with minimal image magnification (only 0–2%), eliminates the problem of "aniseikonia" (difference in image size), and restores the peripheral field of vision. Posterior chamber IOLs (PCIOL) are the gold standard. **Why Other Options are Incorrect:** * **Spectacles:** Once the mainstay, they are now secondary. They cause significant **image magnification (25–30%)**, the "Jack-in-the-box" phenomenon (ring scotoma), and significant distortion, making them unsuitable for unilateral aphakia. * **Contact Lenses:** These are better than spectacles (magnification only 7–10%) and are preferred in **pediatric aphakia** where IOLs cannot be implanted. However, they require high maintenance and are difficult for elderly patients to handle. * **Laser Therapy:** Laser (like LASIK) is used for minor refractive errors but cannot replace the high dioptric power lost in aphakia. **High-Yield Clinical Pearls for NEET-PG:** * **Image Magnification Comparison:** Spectacles (25-30%) > Contact Lenses (7-10%) > IOL (0-2%). * **Unilateral Aphakia:** IOL is mandatory to prevent diplopia and aniseikonia. * **Secondary IOL:** If an IOL wasn't placed during the first surgery, a second procedure is done to implant a Scleral Fixated IOL (SFIOL) or Iris-claw lens. * **Signs of Aphakia:** Deep anterior chamber, **iridodonesis** (tremulousness of iris), and absence of 3rd and 4th Purkinje images.

Question 44: Zonular cataract is seen in?

A. Diabetes mellitus
B. Hypoparathyroidism (Correct Answer)
C. Gaucher's disease
D. Niemann pick disease

Explanation: **Explanation:** **Zonular (Lamellar) Cataract** is the most common type of congenital cataract. It is characterized by opacification of a specific layer (zone) of the lens fibers, usually surrounding a clear embryonic nucleus, with "riders" (linear opacities) extending from the equator. **Why Hypoparathyroidism is Correct:** Hypoparathyroidism leads to **hypocalcemia**. Calcium is essential for maintaining the integrity of the lens fiber membranes and regulating the electrolyte balance within the lens. Low serum calcium levels disrupt the active transport of cations, leading to increased hydration and protein denaturation within specific layers of the lens developing at that time. This results in the classic zonular pattern. **Analysis of Incorrect Options:** * **A. Diabetes Mellitus:** Typically associated with "Snowflake cataracts" (true diabetic cataract) or early-onset senile cataracts (nuclear/cortical). * **C. Gaucher’s Disease:** A lysosomal storage disorder that primarily affects the viscera and CNS; it is not a classic cause of zonular cataracts. * **D. Niemann-Pick Disease:** Another lipid storage disorder. While it can present with a "Cherry-red spot" in the macula, it is not typically associated with zonular cataracts. **NEET-PG High-Yield Pearls:** * **Most common cause of Zonular Cataract:** Vitamin D deficiency (Rickets) and Hypocalcemia/Hypoparathyroidism. * **Morphology:** Look for the keyword **"Riders"**—these are U-shaped opacities that help distinguish zonular cataracts from other types. * **Galactosemia:** Associated with **"Oil droplet"** cataracts. * **Wilson’s Disease:** Associated with **"Sunflower"** cataracts. * **Myotonic Dystrophy:** Associated with **"Christmas tree"** cataracts.

Question 45: What is the primary treatment for traumatic cataract in children?

A. Extra-capsular cataract extraction with intraocular lens implantation (ECCE + IOL)
B. Lensectomy (Correct Answer)
C. Contact lens
D. Glasses

Explanation: **Explanation:** The primary treatment for traumatic cataract in children is **Lensectomy**, often combined with an anterior vitrectomy. This approach is preferred because children have a highly reactive uveal tissue and a thick, elastic posterior capsule. Simple extracapsular techniques frequently lead to rapid development of **Posterior Capsule Opacification (PCO)** and severe inflammatory membranes, which are highly amblyogenic. Lensectomy (removal of the lens, including the capsule) ensures a clear visual axis, which is critical for preventing stimulus-deprivation amblyopia in the developing visual system. **Analysis of Options:** * **A. ECCE + IOL:** While standard in adults, ECCE in children carries a high risk of PCO and "Elschnig pearls." While IOLs are increasingly used in older children, the surgical priority in traumatic cases (especially with capsular rupture or vitreous loss) remains the clearance of the visual axis via lensectomy. * **C & D. Contact Lenses and Glasses:** These are methods for **refractive rehabilitation** (correcting aphakia) after the cataract has been surgically removed. They do not treat the cataract itself. **High-Yield Clinical Pearls for NEET-PG:** * **Amblyopia Risk:** The "golden period" for visual development is up to age 7-8. Any delay in treating a pediatric traumatic cataract leads to irreversible amblyopia. * **Surgical Technique:** In children <6 years, **Primary Posterior Capsulotomy (PPC)** and **Anterior Vitrectomy** are mandatory during cataract surgery to prevent PCO. * **Rosette Cataract:** The classic morphology of a traumatic cataract (concussion injury) is a flower-shaped or rosette cataract. * **Vossius Ring:** A circular ring of iris pigment on the anterior lens capsule, a pathognomonic sign of blunt trauma.

Question 46: What is the best site for a 101 implant?

A. Endocapsular (Correct Answer)
B. Scleral fixation
C. Anterior chamber
D. Iris claw implant

Explanation: **Explanation:** The primary goal of modern cataract surgery (Phacoemulsification or SICS) is to replace the opacified crystalline lens with an **Intraocular Lens (IOL)** in the most anatomical position possible. **Why Endocapsular is the Correct Answer:** The **Endocapsular (In-the-bag)** position is the "gold standard" and the most physiological site for IOL implantation. Placing the IOL within the intact capsular bag ensures: * **Stability:** It prevents IOL tilt and decentration. * **Safety:** It maintains a clear distance from the corneal endothelium and the iris, reducing the risk of bullous keratopathy and uveitis. * **Refractive Predictability:** It provides the most consistent effective lens position (ELP) for accurate power calculation. **Analysis of Incorrect Options:** * **Scleral Fixation (SFIOL):** Used only when there is inadequate capsular or zonular support. It involves suturing the IOL to the sclera, which is surgically demanding and carries risks of suture erosion or endophthalmitis. * **Anterior Chamber (ACIOL):** Placed in front of the iris. It is a backup option but is associated with long-term complications like corneal endothelial cell loss and secondary glaucoma (UGH syndrome). * **Iris Claw Implant (Vasyan Lens):** Clipped onto the iris stroma. While useful in the absence of capsular support, it is not the "best" or primary site due to potential chronic low-grade inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Ideal Site:** Capsular Bag (Endocapsular). * **Second Best Site:** Ciliary Sulcus (only if the posterior capsule is ruptured but the peripheral rim/soemmering ring is intact). * **IOL Material of Choice:** Foldable Hydrophobic Acrylic (lowest rates of PCO). * **Square Edge Design:** The most important feature of an IOL to prevent Posterior Capsular Opacification (PCO).

Question 47: Polyopia is a symptom of which of the following conditions?

A. Cortical cataract (Correct Answer)
B. Cupuliform cataract
C. Radiation cataract
D. Electrical cataract

Explanation: **Explanation:** **Uniocular polyopia** (seeing multiple images of a single object with one eye) is a characteristic symptom of **Cortical Cataract**, specifically during the **incipient stage**. **Why Cortical Cataract is correct:** In cortical cataracts, the opacification occurs in the lens cortex in a wedge-shaped or "cuneiform" pattern. As the hydration of the lens fibers changes, it creates areas of varying refractive indices within the lens. These irregular "water clefts" and sectors act like multiple small prisms, splitting incident light into several foci on the retina. This optical phenomenon results in the perception of multiple images (polyopia). **Why the other options are incorrect:** * **Cupuliform Cataract (Posterior Subcapsular):** This typically presents with significant **glare** and a rapid decrease in near vision. Because it is located centrally and posteriorly, it affects the nodal point of the eye but does not usually create the prismatic effect required for polyopia. * **Radiation Cataract:** These usually manifest as posterior subcapsular opacities (similar to cupuliform) and do not typically present with polyopia. * **Electrical Cataract:** These often present as subcapsular opacities (anterior or posterior) that may mature rapidly but lack the specific cortical hydration pattern associated with polyopia. **High-Yield Clinical Pearls for NEET-PG:** * **Polyopia vs. Diplopia:** Polyopia in cataracts is **uniocular**. If the patient closes the unaffected eye, the symptom persists. * **Stages of Cortical Cataract:** Incipient (Water clefts/Polyopia) → Intumescent (Swollen lens/Glaucoma risk) → Mature (Total opacity) → Hypermature (Morgagnian). * **Cuneiform Cataract:** The most common type of senile cortical cataract, characterized by peripheral wedge-shaped opacities. * **Nuclear Cataract:** Associated with "Second Sight" (myopic shift) rather than polyopia.

Question 48: Which of the following is NOT an indication for intracapsular cataract extraction?

A. Mature cataract in individuals above 45 years of age
B. Immature cataract
C. Subluxated and dislocated lens
D. Mature cataract in individuals aged 30-45 years (Correct Answer)

Explanation: ### Explanation The core concept behind the indications and contraindications for **Intracapsular Cataract Extraction (ICCE)** lies in the strength of the **Zonules of Zinn** (suspensory ligaments). **Why Option D is the Correct Answer:** In individuals younger than 40–45 years, the zonules are extremely strong and the lens is firmly attached to the anterior vitreous face (via the **ligamentum hyaloideum** or Wieger’s ligament). Attempting ICCE in this age group—where the entire lens and capsule are removed—requires excessive force to break these strong zonules. This significantly increases the risk of **vitreous loss**, retinal detachment, and macular edema. Therefore, ICCE is generally contraindicated in patients under 40. **Analysis of Other Options:** * **Option A:** In patients above 45–50 years, the zonules naturally undergo senile degeneration and become fragile. This makes it easier to remove the lens within its capsule, making ICCE a viable (though now largely historical) option. * **Option B:** While not the preferred modern method, an immature cataract can technically be removed via ICCE if the zonules are weak enough. * **Option C:** This is a classic **indication** for ICCE. When a lens is already subluxated or dislocated, the zonular integrity is already compromised. In such cases, removing the entire lens with its capsule is often safer than attempting extracapsular techniques which require an intact capsular bag. **High-Yield Clinical Pearls for NEET-PG:** * **Absolute Contraindications for ICCE:** Congenital/Developmental cataracts and cataracts in children/young adults (due to strong zonules and vitreous adhesion). * **Preferred Technique:** Phacoemulsification is the current gold standard. * **ICCE Complication:** Higher risk of **Aphakic Glaucoma** and **Cystoid Macular Edema (CME)** compared to ECCE/Phaco. * **Enzymatic Zonulolysis:** Alpha-chymotrypsin can be used during ICCE to chemically dissolve zonules in younger patients (30-45 years) if ICCE is absolutely necessary.

Question 49: What is your diagnosis based on the provided image?

A. Cataract
B. Wilson's disease (Correct Answer)
C. Ankylosing spondylitis
D. Behcet syndrome

Explanation: ***Wilson's disease*** - The image shows **Kayser-Fleischer rings** - characteristic greenish-brown copper deposits in **Descemet's membrane** at the corneal periphery, pathognomonic of Wilson's disease. - **Sunflower cataract** may also be present, caused by **copper deposition** in the lens capsule, creating a distinctive radial pattern. *Cataract* - A cataract would present as **lens opacity** with clouding or whitening of the lens, not the distinctive corneal ring pattern seen in the image. - Cataracts cause **visual impairment** but lack the specific **copper-colored deposits** characteristic of Wilson's disease. *Ankylosing spondylitis* - Ocular manifestations include **acute anterior uveitis** with red eye, pain, and photophobia, not corneal rings. - The eye findings would show **inflammatory cells** in the anterior chamber, not the **metallic deposits** visible in this image. *Behçet syndrome* - Typically presents with **hypopyon uveitis** - a white layering of inflammatory cells in the anterior chamber. - Associated with **oral and genital ulcers** and lacks the pathognomonic **corneal copper deposits** seen in Wilson's disease.

Question 50: Sunflower cataract is associated with:

A. Chalcosis (Correct Answer)
B. Juvenile diabetes mellitus
C. Down syndrome
D. Trauma

Explanation: **Explanation:** **Sunflower cataract** is a pathognomonic finding of **Chalcosis**, which refers to the intraocular deposition of copper. This occurs due to a copper-containing intraocular foreign body or systemic conditions like **Wilson’s disease** (hepatolenticular degeneration). The copper deposits in the subcapsular region of the lens, radiating from the center toward the periphery in a petal-like pattern, resembling a sunflower. **Analysis of Options:** * **A. Chalcosis (Correct):** Copper ions deposit in the basement membrane of the lens capsule, forming the characteristic "sunflower" shape. In Wilson’s disease, this is often accompanied by the **Kayser-Fleischer (KF) ring** in the cornea. * **B. Juvenile Diabetes Mellitus:** Associated with **Snowflake cataracts**, which consist of subcapsular opacities that look like white flakes. * **C. Down Syndrome:** Typically associated with **punctate opacities** or "blue dot" (cerulean) cataracts. * **D. Trauma:** Most commonly results in a **Vossius ring** (pigment on the anterior capsule) or a **Rosette-shaped cataract** (stellate opacity along the lens sutures). **High-Yield Clinical Pearls for NEET-PG:** * **Wilson’s Disease Triad:** Sunflower cataract, KF ring (Descemet's membrane), and liver/basal ganglia dysfunction. * **Siderosis Bulbi:** Iron deposition leads to a **rusty brown** discoloration of the lens. * **Christmas Tree Cataract:** Seen in **Myotonic Dystrophy** (polychromatic luster). * **Oil Droplet Cataract:** Classic sign of **Galactosemia**.

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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