Diseases of the Lens — MCQs

Diseases of the Lens Indian Medical PG Practice Questions and MCQs

Question 21: Which of the following is NOT a common complication of intraocular lens (IOL) implantation?

A. Corneal dystrophy (Correct Answer)
B. Glaucoma
C. Anisocoria
D. Macular edema

Explanation: **Explanation:** The correct answer is **A. Corneal dystrophy**. **1. Why Corneal Dystrophy is the correct answer:** Corneal dystrophies are a group of **genetic, bilateral, and progressive** disorders (e.g., Fuchs' endothelial dystrophy) that are determined at birth, though they may manifest later in life. They are not caused by external factors like surgery. In contrast, surgical trauma to the corneal endothelium during IOL implantation can lead to **Pseudophakic Bullous Keratopathy (PBK)** or corneal edema, but this is an acquired condition, not a "dystrophy." **2. Why the other options are common complications:** * **Glaucoma (B):** Post-operative intraocular pressure (IOP) spikes can occur due to retained viscoelastic material, inflammatory debris (uveitis), or pupillary block. Chronic secondary glaucoma can also occur. * **Anisocoria (C):** Unequal pupil size is common post-surgery due to mechanical trauma to the iris sphincter, the use of miotics/mydriatics, or iris incarceration in the wound. * **Macular Edema (D):** Specifically known as **Irvine-Gass Syndrome**, this is a well-known complication of cataract surgery occurring due to inflammatory mediators reaching the posterior segment, typically 4–6 weeks post-op. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication of IOL surgery:** Posterior Capsular Opacification (PCO), also known as "After Cataract." * **Treatment for PCO:** Nd:YAG Laser Capsulotomy. * **Irvine-Gass Syndrome:** Diagnosed via Fundus Fluorescein Angiography (FFA), showing a characteristic **"Flower-petal appearance"** due to leakage in the Henle’s layer. * **Toxic Anterior Segment Syndrome (TASS):** An acute sterile postoperative inflammation occurring within 12–24 hours, often due to contaminated instruments or solutions.

Question 22: What is the most common complication after lens extraction in persistent hyperplastic primary vitreous?

A. Orbital cellulitis
B. Retinal detachment
C. Vitreous hemorrhage (Correct Answer)
D. Keratitis

Explanation: **Explanation:** **Persistent Hyperplastic Primary Vitreous (PHPV)**, now more commonly referred to as **Persistent Fetal Vasculature (PFV)**, is a congenital anomaly resulting from the failure of the embryological primary vitreous and hyaloid vascular system to regress. **Why Vitreous Hemorrhage is the correct answer:** The hallmark of PHPV is a fibrovascular membrane located behind the lens. This membrane is highly vascularized and often contains a persistent, patent **hyaloid artery**. During lens extraction (cataract surgery), the surgical manipulation or excision of this retrolental membrane frequently leads to the rupture of these primitive, fragile vessels. Because these vessels are directly connected to the hyaloid system, **vitreous hemorrhage** is the most common and significant intraoperative/postoperative complication. **Analysis of Incorrect Options:** * **A. Orbital Cellulitis:** This is an acute infection of the orbital tissues, usually secondary to sinusitis or trauma. It is an extremely rare complication of intraocular surgery and not specific to PHPV. * **B. Retinal Detachment:** While PHPV is associated with tractional retinal detachment due to the fibrovascular stalk pulling on the retina, it is generally considered a less frequent immediate complication of the lens extraction itself compared to hemorrhage. * **D. Keratitis:** This refers to corneal inflammation. While transient corneal edema can occur after any intraocular surgery, keratitis is not a characteristic complication associated with the vascular pathology of PHPV. **High-Yield Clinical Pearls for NEET-PG:** * **Presentation:** Typically unilateral, presenting with leucocoria (white pupillary reflex) and microphthalmos. * **Mittendorf dot:** A remnant of the hyaloid artery on the posterior lens capsule (anterior PHPV). * **Bergmeister’s papilla:** A remnant of the hyaloid artery at the optic disc (posterior PHPV). * **Management Tip:** Pre-operative ultrasound (B-scan) is essential to identify the persistent hyaloid stalk and assess for associated retinal detachment.

Question 23: Which type of cataract is reversible with treatment?

A. Diabetic cataract
B. Oil drop cataract (Correct Answer)
C. Chalcosis
D. Shield cataract

Explanation: **Explanation:** The correct answer is **Oil drop cataract**, which is the characteristic clinical finding in **Galactosemia** (specifically Galactose-1-phosphate uridyltransferase deficiency). **1. Why Oil drop cataract is correct:** In galactosemia, the accumulation of galactose in the lens is converted into **dulcitol (galactitol)** by the enzyme aldose reductase. Dulcitol is osmotically active, drawing water into the lens fibers and causing early opacification. If the condition is diagnosed early and the child is placed on a **lactose-free/galactose-free diet**, the metabolic process can be halted and the early lens changes are **reversible**. **2. Why other options are incorrect:** * **Diabetic cataract:** While "Snowflake cataracts" occur due to sorbitol accumulation (similar osmotic mechanism), they typically progress to permanent structural protein damage and are not considered clinically reversible once established. * **Chalcosis:** This refers to the deposition of copper in the lens (Sunflower cataract) due to an intraocular foreign body or Wilson’s disease. While the copper may be removed, the structural damage/opacity is generally permanent. * **Shield cataract:** This is a dense, anterior subcapsular plaque-like opacity seen in patients with **Atopic Keratoconjunctivitis**. It is a chronic inflammatory/mechanical change and is irreversible. **Clinical Pearls for NEET-PG:** * **Galactosemia:** Most common cause of "Oil drop" appearance. * **Galactokinase deficiency:** Only causes cataracts without the systemic features (liver/brain damage) of classic galactosemia. * **Snowflake cataract:** Classic for Juvenile Diabetes Mellitus. * **Sunflower cataract:** Classic for Wilson’s Disease (Copper). * **Christmas tree cataract:** Classic for Myotonic Dystrophy.

Question 24: Extra capsular extraction of the lens is not possible in which of the following conditions?

A. Hypermature cataract
B. Immature cataract
C. Lens subluxation (Correct Answer)
D. Developmental cataract

Explanation: **Explanation:** The core requirement for an **Extracapsular Cataract Extraction (ECCE)**, including modern Phacoemulsification, is a **stable and intact capsular bag** supported by healthy zonules. **Why Lens Subluxation is the Correct Answer:** In lens subluxation, the zonules (suspensory ligaments) are weak or broken. During ECCE, the surgeon removes the anterior capsule and the lens nucleus while leaving the posterior capsule in place. If the zonules are compromised, the entire capsular bag becomes unstable. Attempting ECCE in a subluxated lens risks the entire lens (or its fragments) falling into the vitreous cavity. Therefore, **Intracapsular Cataract Extraction (ICCE)**—where the entire lens along with the intact capsule is removed—or a specialized Pars Plana Lensectomy is indicated instead. **Analysis of Incorrect Options:** * **Immature & Hypermature Cataracts:** These represent stages of cortical/nuclear degeneration. As long as the zonular integrity is maintained, the lens can be safely removed via ECCE. In hypermature cataracts, the capsule may be fragile, but ECCE remains the standard approach. * **Developmental Cataract:** These occur in children/young adults. Since the zonules are typically strong, ECCE (specifically lens aspiration) is the procedure of choice. **High-Yield Clinical Pearls for NEET-PG:** * **Absolute Contraindication for ECCE:** Significant zonular dehiscence (>180 degrees) or lens subluxation. * **Indications for ICCE:** Subluxated/dislocated lens, very hard cataracts where phacoemulsification is risky, and in resource-limited settings. * **Zonular Weakness:** Always suspect in cases of Marfan Syndrome, Homocystinuria, or ocular trauma. * **Modern Management:** For mild subluxation, ECCE can sometimes be performed using a **Capsular Tension Ring (CTR)** to stabilize the bag, but classic subluxation remains a textbook indication for ICCE.

Question 25: Kayser-Fleischer rings are associated with which of the following conditions?

A. Oil drop cataract
B. Rosette cataract
C. Snowflake cataract
D. Sunflower cataract (Correct Answer)

Explanation: **Explanation:** The correct answer is **Sunflower cataract**. Both Kayser-Fleischer (KF) rings and Sunflower cataracts are ocular manifestations of **Wilson’s Disease** (Hepatolenticular degeneration), a disorder of copper metabolism. In Wilson’s Disease, a deficiency of the enzyme ceruloplasmin leads to the deposition of excess free copper in various tissues. * **Kayser-Fleischer Ring:** Copper deposits in the **Descemet’s membrane** of the peripheral cornea, appearing as a golden-brown or greenish ring. * **Sunflower Cataract (Chalcosis Lentis):** Copper deposits under the **anterior lens capsule**, radiating outward in a petal-like configuration. **Analysis of Incorrect Options:** * **A. Oil drop cataract:** Characteristically seen in **Galactosemia**. It is caused by the accumulation of dulcitol in the lens, creating a central refractive change resembling a drop of oil. * **B. Rosette cataract:** A classic sign of **Blunt Ocular Trauma**. It occurs due to the separation of lens fibers at the sutures, usually appearing in the subcapsular region. * **C. Snowflake cataract:** Associated with **Diabetes Mellitus** (specifically juvenile/Type 1). These are subcapsular opacities that appear as white, needle-like spots. **High-Yield Clinical Pearls for NEET-PG:** * **KF Ring** is the most common ocular sign of Wilson’s Disease (95% of patients with neurological symptoms). * **Sunflower cataract** does not typically impair vision significantly. * Both ocular signs may **disappear** with systemic chelation therapy (e.g., D-Penicillamine). * **Copper deposition** in the eye is specifically termed **Chalcosis**.

Question 26: What is a known complication of extra capsular lens extraction?

A. Cystoid macular edema
B. Opacification of the capsule
C. Iritis
D. All of the above (Correct Answer)

Explanation: **Explanation:** Extra Capsular Cataract Extraction (ECCE) involves the removal of the lens nucleus and cortex while leaving the posterior capsule intact. While this provides structural support for an Intraocular Lens (IOL), it is associated with several postoperative complications. **Why "All of the above" is correct:** * **Opacification of the Capsule (Option B):** This is the **most common** late complication of ECCE. It occurs due to the proliferation and migration of residual lens epithelial cells (LECs) onto the posterior capsule, forming "Elschnig’s pearls" or "Soemmering’s ring." * **Cystoid Macular Edema (CME) (Option A):** Also known as Irvine-Gass Syndrome, CME can occur after any intraocular surgery. Inflammatory mediators (prostaglandins) released during the procedure lead to increased capillary permeability in the macula, causing fluid accumulation in the Henle’s layer. * **Iritis (Option C):** Surgical trauma and the manipulation of intraocular tissues (especially the iris) often trigger an inflammatory response, leading to postoperative anterior uveitis or iritis. **High-Yield Clinical Pearls for NEET-PG:** * **Posterior Capsule Opacification (PCO):** The definitive treatment for PCO is **Nd:YAG Laser Capsulotomy**. * **CME Diagnosis:** The gold standard for diagnosis is **Fluorescein Angiography (FFA)**, which shows a characteristic "flower-petal" pattern of leakage. * **Comparison:** Compared to Intracapsular Cataract Extraction (ICCE), ECCE has a significantly lower risk of vitreous loss and retinal detachment because the posterior capsule remains as a barrier. * **Modern Standard:** While ECCE is still tested, Phacoemulsification (a form of ECCE) is the current standard of care due to smaller incisions and faster recovery.

Question 27: Shallow anterior chamber is seen in which of the following conditions?

A. Mature cataract
B. Hypermature cataract
C. Intumescent cataract (Correct Answer)
D. Incipient cataract

Explanation: ### Explanation The depth of the anterior chamber (AC) is significantly influenced by the size and position of the crystalline lens. **1. Why Intumescent Cataract is correct:** In the **intumescent stage**, the lens fibers imbibe fluid (osmotic hydration), causing the lens to become **swollen and globular**. This increased anteroposterior thickness of the lens pushes the iris-lens diaphragm forward, resulting in a **shallow anterior chamber**. This is clinically significant as it can lead to secondary angle-closure glaucoma (Phacomorphic glaucoma). **2. Why the other options are incorrect:** * **A. Mature Cataract:** The lens is completely opaque, but the hydration has stabilized. The lens volume is generally normal, so the AC depth remains normal. * **B. Hypermature Cataract:** In the **Morgagnian** or **Sclerotic** types, the lens loses fluid and shrinks (capsular wrinkling). This causes the iris to fall back, leading to a **deep anterior chamber**. * **C. Incipient Cataract:** This is the earliest stage where small opacities (wedges/sectors) appear. The lens volume does not change significantly at this stage, so the AC depth remains normal. **High-Yield Clinical Pearls for NEET-PG:** * **Phacomorphic Glaucoma:** Caused by an **Intumescent cataract** (swollen lens → shallow AC → angle closure). * **Phacolytic Glaucoma:** Caused by a **Hypermature cataract** (leakage of lens proteins → macrophages clog the trabecular meshwork → deep AC). * **Iris Shadow Test:** Positive in immature/intumescent cataracts; negative in mature cataracts (as no clear cortex remains between the iris and the opacity). * **Deep AC** is also seen in: Aphakia, Posterior dislocation of the lens, and Buphthalmos.

Question 28: The commonest type of cataract in adults is:

A. Nuclear cataract
B. Cortical cataract (Correct Answer)
C. Morgagnian cataract
D. None of the above

Explanation: **Explanation:** The correct answer is **B. Cortical cataract**. In the context of age-related (senile) cataracts, **cortical cataract** is statistically the most common morphological type encountered in adults. It occurs due to the hydration of lens fibers, leading to the formation of fluid-filled vacuoles and "cuneiform" (wedge-shaped) opacities that typically begin in the periphery and progress toward the center. **Analysis of Options:** * **A. Nuclear cataract:** This is the second most common type. It is characterized by the intensification of age-related sclerosis and deposition of urochrome pigment, leading to a yellow or brown discoloration (brunescent cataract). It is classically associated with "second sight" due to an induced myopic shift. * **C. Morgagnian cataract:** This is not a primary type but rather a stage of hypermature cortical cataract. In this stage, the cortex completely liquefies, allowing the dense, brownish nucleus to settle at the bottom of the capsular bag. * **D. None of the above:** Incorrect, as cortical cataract is the established commonest type. **High-Yield Clinical Pearls for NEET-PG:** * **Most common type overall:** Cortical cataract. * **Most common type causing "Second Sight":** Nuclear cataract (due to index myopia). * **Most common type associated with Diabetes:** Cortical cataract (though Posterior Subcapsular Cataract is also highly characteristic). * **Fastest progressing senile cataract:** Posterior Subcapsular Cataract (PSC). * **Cupuliform cataract:** Another name for Posterior Subcapsular Cataract. * **Cuneiform cataract:** Another name for Cortical cataract.

Question 29: Which of the following factors is not responsible for lens transparency?

A. Avascularity
B. Antioxidants
C. Aquaporins
D. Hydration (Correct Answer)

Explanation: ### Explanation The transparency of the crystalline lens is maintained by its unique structural organization and metabolic control. The correct answer is **Hydration**, specifically because **dehydration (relative)**—not hydration—is the physiological state required for transparency. **1. Why Hydration is the correct answer:** The lens is approximately 66% water and 33% protein. Maintaining a state of **relative dehydration** is critical. If the water content increases (over-hydration), it disrupts the regular lattice arrangement of lens fibers, leading to light scattering and opacification (cataract formation). This is why conditions like osmotic stress in diabetes lead to cataracts. **2. Why the other options are wrong:** * **Avascularity:** The absence of blood vessels prevents light scattering. The lens receives nutrients via the aqueous humor to ensure there are no opaque elements in the light path. * **Antioxidants:** The lens is rich in **Glutathione** and Vitamin C. These protect lens proteins from oxidative damage and photo-oxidation, preventing the aggregation of proteins (crystallins) that causes opacification. * **Aquaporins:** Specifically **AQP0** (the most abundant protein in the lens membrane), these channels are vital for the "Internal Circulatory System" of the lens. They facilitate water transport and maintain the precise ionic balance and hydrostatic pressure required for transparency. **Clinical Pearls for NEET-PG:** * **Pump-Leak Hypothesis:** Transparency is maintained by an active Na+/K+ ATPase pump (located in the anterior epithelium) that counters the constant passive leak of ions. * **Crystallins:** These are specialized proteins packed in a paracrystalline lattice. The distance between them must be less than half the wavelength of light to minimize scattering (Maurice’s Theory). * **Lens Fibers:** The loss of organelles (nuclei, mitochondria) in the mature lens fibers creates an "organelle-free zone," further reducing light interference.

Question 30: Which of the following conditions can give rise to sunflower cataract?

A. Diabetes mellitus
B. Injuries
C. Chalcosis (Correct Answer)
D. Infections

Explanation: **Explanation:** **Sunflower cataract** is a pathognomonic finding of **Chalcosis**, which refers to the intraocular deposition of copper. When a copper-containing foreign body enters the eye, copper ions dissolve and deposit in basement membranes. In the lens, copper accumulates under the posterior lens capsule and in the pupillary area of the anterior capsule. It appears as a central disc with radiating petal-like spokes, resembling a sunflower. This is typically reversible if the foreign body is removed. **Analysis of Options:** * **Diabetes Mellitus (A):** Characteristically causes **"Snowflake cataracts"** (subcapsular opacities) due to the accumulation of sorbitol and osmotic swelling of lens fibers. * **Injuries (B):** Blunt trauma typically results in a **"Vossius ring"** (pigment on the anterior capsule) or a **"Rosette-shaped cataract"** (stellate opacity along lens sutures). * **Infections (C):** Intraocular infections (Endophthalmitis) generally lead to inflammatory exudates or generalized lens opacification rather than specific morphological patterns like a sunflower cataract. **High-Yield Clinical Pearls for NEET-PG:** * **Wilson’s Disease:** A systemic cause of sunflower cataract due to an inborn error of copper metabolism (deficiency of Ceruloplasmin). It is also associated with the **Kayser-Fleischer (KF) ring** in the Descemet’s membrane of the cornea. * **Siderosis Bulbi:** Caused by an iron foreign body; results in a **rusty brown discoloration** of the lens (Cataracta lentis browni). * **Christmas Tree Cataract:** Seen in **Myotonic Dystrophy**, characterized by polychromatic needle-like crystals. * **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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