Diseases of the Lens Practice Questions

Q: A baby is brought to the ophthalmology department with congenital cataract involving the visual axis. What is the MOST appropriate management in this baby?

Immediate operation. **Explanation:** The management of congenital cataract is guided by the risk of **amblyopia** (lazy eye). When a cataract involves the **visual axis** (e.g., central, dense, or >3mm), it causes stimulus deprivation. If not treated promptly, this leads to irreversible **stimulus-deprivation amblyopia**, as the brain fails to develop the neural pathways for vision during the critical period of visual development. **Why Option A is correct:** Immediate surgical intervention (Lens aspiration with/without IOL) is mandatory for cataracts obstructing the visual axis to allow light to reach the retina, ensuring normal visual development. The ideal time for surgery in unilateral cases is within 4–6 weeks of birth, and for bilateral cases, within 8–10 weeks. **Why other options are incorrect:** * **B. Wait and watch:** Delaying surgery in a visually significant cataract leads to permanent visual loss due to amblyopia. * **C. Mydriatics:** While pupillary dilation can sometimes be used for small, central cataracts to allow light to pass around the opacity, it is not the definitive treatment for cataracts involving the visual axis. * **D. Operate in adulthood:** By adulthood, the critical period for visual development has passed. Surgery at this stage may clear the ocular media, but the eye will remain amblyopic with poor visual prognosis. **Clinical Pearls for NEET-PG:** * **Most common cause of congenital cataract:** Idiopathic (Overall); **Rubella** (Infectious). * **Morphology:** **Zonular (Lamellar) cataract** is the most common type of congenital cataract. * **Surgical Technique:** In infants, the procedure of choice is **Lens Aspiration + Posterior Capsulotomy + Anterior Vitrectomy** (to prevent Posterior Capsular Opacification). * **IOL Implantation:** Generally avoided in infants <6 months; primary IOL is usually considered after 1–2 years of age.

Q: Intraocular lenses are made up of which material?

PMMA. **Explanation:** The correct answer is **PMMA (Polymethylmethacrylate)**. PMMA is a rigid, transparent, and biocompatible thermoplastic that has been the "gold standard" for non-foldable intraocular lenses (IOLs) for decades. Its use in ophthalmology was pioneered by **Sir Harold Ridley** in 1949, who observed that Spitfire pilots with retained cockpit canopy fragments (made of PMMA) in their eyes did not show significant inflammatory reactions. **Analysis of Options:** * **PMMA (Correct):** It is highly stable, has excellent optical clarity, and is inert within the eye. However, because it is rigid, it requires a larger incision (approx. 5–6 mm) for insertion. * **HEMA (Hydroxyethylmethacrylate):** This is a hydrophilic material primarily used in the manufacturing of **soft contact lenses**, not standard IOLs. While some "hydrogel" IOLs exist, HEMA is not the primary material for IOLs. * **Glass:** Although glass has high optical quality, it is heavy, fragile, and difficult to sterilize/handle safely within the eye. It is not used for modern IOLs. * **Plastic:** This is a generic term. While PMMA is a type of plastic, in medical exams, the specific chemical name (PMMA) is always the preferred, more accurate answer. **High-Yield Clinical Pearls for NEET-PG:** * **Foldable IOLs:** Modern cataract surgery (Phacoemulsification) uses foldable IOLs made of **Silicone** or **Acrylic** (Hydrophobic/Hydrophilic) to allow insertion through micro-incisions (<3 mm). * **Square Edge Design:** Modern IOLs have a square posterior edge to prevent **Posterior Capsular Opacification (PCO)**, the most common late complication of cataract surgery. * **Heparin-coated IOLs:** Used in patients with uveitis to reduce postoperative inflammation. * **Multifocal/Toric IOLs:** Used to correct presbyopia and pre-existing astigmatism, respectively.

Q: What is the most common type of senile cataract associated with glaucoma?

Morgagnian hypermature. **Explanation:** The correct answer is **Morgagnian hypermature cataract**. This association is primarily due to the risk of **Phacolytic Glaucoma**. **Why Morgagnian Hypermature is Correct:** In a Morgagnian cataract, the cortex undergoes complete liquefaction, allowing the dense nucleus to sink inferiorly within the capsular bag. As the lens capsule becomes leaky, high-molecular-weight lens proteins escape into the anterior chamber. These proteins are engulfed by macrophages, which then clog the trabecular meshwork, leading to a secondary open-angle glaucoma known as **Phacolytic Glaucoma**. Additionally, an intumescent (swollen) lens can cause pupillary block, leading to **Phacomorphic Glaucoma**. **Analysis of Incorrect Options:** * **Incipient type:** This is the earliest stage of cataract formation with minimal lens changes (e.g., cuneiform opacities). It does not typically cause a rise in intraocular pressure. * **Nuclear type:** While nuclear sclerosis increases the refractive power (index myopia), it rarely causes glaucoma unless the lens becomes exceptionally large (brunescent stage), but it is far less common than the Morgagnian type. * **Sclerotic hypermature:** In this stage, the lens becomes shrunken and wrinkled due to the loss of water. While it can cause lens-induced uveitis (Phacoantigenic glaucoma), it is less frequently associated with acute glaucoma compared to the liquefied Morgagnian type. **High-Yield Clinical Pearls for NEET-PG:** * **Phacolytic Glaucoma:** Secondary open-angle glaucoma; characterized by a deep anterior chamber and "white spots" (macrophages) on the lens capsule. * **Phacomorphic Glaucoma:** Secondary angle-closure glaucoma; caused by an intumescent lens pushing the iris forward. * **Treatment:** The definitive management for both is the urgent reduction of IOP followed by cataract extraction.

Q: Posterior subcapsular stellate cataract is typically seen in which of the following conditions?

Myotonic Dystrophy. **Explanation:** **Myotonic Dystrophy (Option C)** is the correct answer. The characteristic ocular finding in this condition is the **"Christmas Tree Cataract,"** which consists of polychromatic, iridescent crystals in the lens cortex. Over time, these progress to form a **posterior subcapsular stellate (star-shaped) cataract**. This is a high-yield association for NEET-PG, often linked to the genetic defect on chromosome 19 (DM1). **Analysis of Incorrect Options:** * **Wilson’s Disease (Option A):** Associated with the **"Sunflower Cataract"** (anterior subcapsular deposits of copper) and the more common Kayser-Fleischer (KF) ring in the Descemet’s membrane. * **Diabetes Mellitus (Option B):** Classically associated with **"Snowflake Cataracts"** (subcapsular opacities) in young patients with uncontrolled Type 1 DM, and earlier onset of senile nuclear sclerosis in Type 2 DM. * **Systemic Lupus Erythematosus (Option D):** While SLE itself doesn't cause a specific cataract, the long-term use of **Steroids** to treat SLE is a well-known cause of posterior subcapsular cataracts (PSC), but these are typically not described as "stellate." **High-Yield Clinical Pearls for NEET-PG:** * **Rosette-shaped/Flower-shaped Cataract:** Traumatic cataract (concussion injury). * **Oil Droplet Cataract:** Galactosemia. * **Glass-blower’s Cataract:** Infrared radiation (True exfoliation of the capsule). * **Shield Cataract:** Atopic dermatitis. * **Bread-crumb appearance:** Complicated cataract (secondary to uveitis).

Q: Congenital morgagnian cataract is a feature of which of the following conditions?

Rubella. **Explanation:** **Congenital Rubella Syndrome (CRS)** is the classic cause of a **congenital morgagnian cataract**. In this condition, the rubella virus directly invades the lens during the first trimester of pregnancy. The virus causes total liquefaction of the lens cortex, leading to a milky-white appearance where the dense nucleus sinks to the bottom of the capsular bag—the defining feature of a morgagnian cataract. **Analysis of Options:** * **A. Rubella (Correct):** It is the only condition among the choices where the virus persists in the lens for years post-birth, causing progressive cortical liquefaction. * **B. Lowe’s Syndrome (Oculo-cerebro-renal syndrome):** Characterized by **small, thin, disc-like (microspherophakic)** cataracts. It is an X-linked recessive disorder associated with aminoaciduria and glaucoma. * **C. Hereditary Cataract:** Most commonly presents as **Zonular (Lamellar) cataract**, which is the most frequent type of congenital cataract overall. * **D. Galactosemic Cataract:** Classically presents as an **"Oil droplet" cataract** due to the accumulation of dulcitol (galactitol) within the lens fibers, leading to osmotic swelling. **High-Yield Clinical Pearls for NEET-PG:** 1. **Gregg’s Triad (CRS):** Cataract, Sensorineural deafness, and Cardiac defects (PDA is most common). 2. **Surgical Note:** In Rubella cataracts, the virus can remain live within the lens for up to 3 years. Surgery (aspiration) may release the virus, leading to severe postoperative endophthalmitis. 3. **Morgagnian Cataract:** While typically an advanced stage of senile cataract (hypermature), its presence at birth is almost pathognomonic for Rubella.

Q: Which of the following materials is used in hard intraocular lenses (IOLs)?

Polymethyl methacrylate (PMMA). **Explanation:** The classification of Intraocular Lenses (IOLs) is primarily based on the material's flexibility, which determines the incision size required during cataract surgery. **Why PMMA is correct:** **Polymethyl methacrylate (PMMA)** is a rigid, non-foldable plastic. It was the first material used for IOLs (by Sir Harold Ridley in 1949). Because it is a **hard material**, it does not fold; therefore, it requires a larger incision (approx. 5.5 to 6.5 mm) equal to the diameter of the optic. It is highly biocompatible, optically clear, and remains the gold standard for "hard" IOLs, often used in ECCE (Extracapsular Cataract Extraction). **Why other options are incorrect:** * **Silicon:** This is a **foldable (soft)** material. It was the first foldable material used, allowing for smaller incisions, but it is less preferred today in eyes with silicone oil (e.g., vitreoretinal surgery) due to oil-lens adherence. * **Hydrogel:** These are **foldable** lenses made of hydroxyethyl methacrylate (HEMA). They have high water content but are less commonly used now due to a higher risk of calcification. * **Acrylic:** Available in both hydrophobic and hydrophilic forms, acrylic is the most popular **foldable** material used in modern Phacoemulsification. It allows for micro-incisions (as small as 1.8 to 2.2 mm). **High-Yield Clinical Pearls for NEET-PG:** * **Sir Harold Ridley:** The "Father of Modern IOL," who observed that PMMA splinters from Spitfire cockpits were inert in the eyes of WWII pilots. * **Square Edge Design:** Modern IOLs (especially Acrylic) use a square posterior edge to reduce the incidence of **Posterior Capsular Opacification (PCO)**. * **Ideal Site:** The **Capsular Bag** ("In-the-bag") is the most preferred anatomical site for IOL placement.

Q: Cataract brunescens results due to deposition of:

Urochrome. **Explanation:** **Cataract Brunescens** (Brown Cataract) is an advanced stage of nuclear sclerosis where the lens nucleus becomes intensely hard and turns a dark brown color. **1. Why Urochrome is correct:** In the aging lens, soluble proteins (crystallins) undergo progressive denaturation and aggregation. This process is accompanied by the accumulation of **urochrome** (a pigment derived from the amino acid tyrosine) and other melanin-like pigments. These pigments absorb shorter wavelengths of light, leading to the characteristic amber, brown, or even black (cataract nigra) discoloration of the lens nucleus. **2. Why other options are incorrect:** * **Copper (Option B):** Deposition of copper in the lens leads to a **Sunflower Cataract** (Chalcosis lentis), typically seen in Wilson's disease or intraocular copper foreign bodies. * **Iron (Option C):** Deposition of iron leads to **Siderosis lentis**, characterized by rusty-brown subcapsular deposits, often due to a retained iron-containing intraocular foreign body. * **Silver (Option D):** Chronic silver toxicity (Argyrosis) causes a slate-grey discoloration of the conjunctiva and Descemet’s membrane, but not typically a brunescent cataract. **Clinical Pearls for NEET-PG:** * **Nuclear Cataract Grading:** Progresses from immature (yellow) → Brunescent (brown) → Nigra (black). * **Refractive Shift:** Nuclear sclerosis causes an increase in the refractive index of the lens, leading to **index myopia** (patients often report a "second sight" or improved near vision). * **Surgical Note:** Brunescent cataracts are very hard; they require higher phacoemulsification power and carry a higher risk of posterior capsular rupture or corneal endothelial damage.

Q: Which of the following is not a cause of cataract?

Hypomagnesemia. **Explanation:** The correct answer is **Hypomagnesemia**. While various electrolyte imbalances and metabolic disorders are associated with lens opacification, hypomagnesemia is not a recognized cause of cataract. In contrast, **Hypocalcemia** is a well-known cause (producing "sunflower" or punctate iridescent cataracts). **Analysis of Options:** * **Diabetes Mellitus (A):** High glucose levels in the aqueous humor lead to the accumulation of **sorbitol** within the lens via the polyol pathway. This creates an osmotic gradient, drawing water into the lens fibers, leading to "Snowflake cataracts" (classic in Type 1) or accelerated senile cataracts. * **Wilson Disease (B):** This disorder of copper metabolism leads to copper deposition in the lens capsule, resulting in the pathognomonic **"Sunflower Cataract"** (distinct from the Kayser-Fleischer ring, which occurs in the cornea). * **Galactosemia (C):** Deficiency of GALT or galactokinase leads to the accumulation of **dulcitol** (galactitol) in the lens. This causes osmotic swelling, classically presenting as a **"Oil Droplet Cataract"** in early infancy. **High-Yield Clinical Pearls for NEET-PG:** 1. **Hypocalcemia:** Causes "Zonular" or punctate cataracts (not hypercalcemia). 2. **Myotonic Dystrophy:** Associated with **"Christmas Tree Cataracts"** (polychromatic luster). 3. **Atopic Dermatitis:** Associated with **"Shield Cataracts"** (anterior subcapsular). 4. **Steroids:** Characteristically cause **Posterior Subcapsular Cataracts (PSC)**. 5. **Down Syndrome:** Often presents with "snowflake" or punctate opacities.

Question 1

A baby is brought to the ophthalmology department with congenital cataract involving the visual axis. What is the MOST appropriate management in this baby?

Accepted Answer

Immediate operation

Answer

Wait and watch

Answer

Mydriatics

Answer

Operate in adulthood

Question 2

After radiation-induced injury, which part of the lens is NOT typically affected by cataract formation?

Accepted Answer

Sub-capsular region

Answer

Anterior cortex

Answer

Posterior cortex

Answer

Nucleus

Question 3

What is the biochemistry of cataract formation?

Accepted Answer

Denaturation of lens proteins

Answer

Hydration intumescence

Answer

Slow sclerosis

Answer

All of the above

Question 4

Intraocular lenses are made up of which material?

Accepted Answer

PMMA

Answer

HEMA

Answer

Glass

Answer

Plastic

Question 5

What is the most common type of senile cataract associated with glaucoma?

Accepted Answer

Morgagnian hypermature

Answer

Incipient type

Answer

Nuclear type

Answer

Sclerotic hypermature

Question 6

Posterior subcapsular stellate cataract is typically seen in which of the following conditions?

Accepted Answer

Myotonic Dystrophy

Answer

Wilson's disease

Answer

Diabetes Mellitus

Answer

Systemic Lupus Erythematosus

Question 7

Congenital morgagnian cataract is a feature of which of the following conditions?

Accepted Answer

Rubella

Answer

Lowe's syndrome

Answer

Hereditary cataract

Answer

Galactosemic cataract

Question 8

Which of the following materials is used in hard intraocular lenses (IOLs)?

Accepted Answer

Polymethyl methacrylate (PMMA)

Answer

Silicon

Answer

Hydrogel

Answer

Acrylic

Question 9

Cataract brunescens results due to deposition of:

Accepted Answer

Urochrome

Answer

Copper

Answer

Iron

Answer

Silver

Question 10

Which of the following is not a cause of cataract?

Accepted Answer

Hypomagnesemia

Answer

Diabetes

Answer

Wilson disease

Answer

Galactosemia

Diseases of the Lens — MCQs

Diseases of the Lens — MCQs

On this page

Practice by Chapter

Want unlimited practice?