Diseases of the Lens Practice Questions

Q: Complicated cataract is associated with which of the following conditions?

All of the above. ### Explanation **Concept:** A **complicated cataract** refers to opacification of the lens resulting from metabolic disturbances caused by intraocular diseases. The lens depends on the aqueous and vitreous humor for nutrition; any chronic inflammation or degenerative process in the eye alters this environment, leading to the accumulation of toxins and interference with lens metabolism. **Why "All of the Above" is Correct:** 1. **Uveitis (Chronic Iridocyclitis):** This is the most common cause. Persistent inflammation leads to the release of inflammatory mediators and proteins into the aqueous humor, which damages the lens epithelium. 2. **Retinitis Pigmentosa (RP):** This retinal dystrophy is classically associated with **posterior subcapsular cataracts (PSC)**. The mechanism involves the migration of metabolic byproducts or inflammatory cells from the degenerating retina toward the posterior pole of the lens. 3. **Degenerative Myopia:** High myopia causes vitreous liquefaction and chorioretinal degeneration. These degenerative changes alter the nutritional supply to the lens, frequently resulting in early-onset posterior subcapsular or nuclear opacities. **Clinical Pearls for NEET-PG:** * **Morphology:** Complicated cataracts typically begin as a **"Bread-crumb" appearance** (polychromatic luster) in the posterior subcapsular region. * **Characteristic Sign:** The presence of a **polychromatic luster** (iridescence of reds, greens, and blues) is a pathognomonic finding on slit-lamp examination. * **Other Causes:** Retinal detachment (long-standing), intraocular tumors (e.g., retinoblastoma), and absolute glaucoma. * **Surgical Note:** Prognosis after surgery depends on the health of the underlying retina/uvea, not just the successful removal of the lens.

Q: In complicated cataract, opacity develops in which part of the lens?

Posterior subcapsular. **Explanation:** **Complicated cataract** refers to the opacification of the lens secondary to intraocular diseases, most commonly chronic anterior uveitis. **Why Posterior Subcapsular (PSC) is correct:** The lens is an avascular structure that derives its nutrition from the aqueous humor. In conditions like chronic uveitis, the inflammatory mediators and toxins present in the aqueous humor interfere with lens metabolism. The **posterior pole** is the most vulnerable site because it is the thinnest part of the lens capsule and lacks a protective epithelial layer (which is present anteriorly). This leads to the accumulation of fluid and denatured proteins, resulting in a characteristic **"bread-crumb"** or **polychromatic luster** appearance in the posterior subcapsular region. **Why other options are incorrect:** * **Anterior capsule:** Opacities here are typically associated with trauma, pseudoexfoliation, or "Glaukomflecken" (post-acute congestive glaucoma). * **Nucleus:** Nuclear cataracts are primarily age-related (senile) due to the compaction and sclerosis of central lens fibers. * **Cortical:** Cortical cataracts are usually age-related or metabolic (e.g., diabetes) and present as "cuneiform" or wedge-shaped opacities. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Chronic Anterior Uveitis. * **Earliest sign:** A **polychromatic luster** (iridescence) seen at the posterior pole. * **Appearance:** Often described as a **"bread-crumb"** appearance. * **Other causes:** High myopia, Retinitis Pigmentosa, and long-term steroid use (though steroid-induced PSC is technically a drug-induced cataract, it mimics the morphology).

Q: A 70-year-old man presents with deterioration of vision 3 weeks after cataract extraction and intraocular lens implantation. Slit lamp examination shows honeycomb maculopathy and Fluorescein angiography shows 'flower petal' hyperfluorescence. What is the most likely diagnosis?

Cystoid macular edema. ### Explanation The correct diagnosis is **Cystoid Macular Edema (CME)**, specifically known as **Irvine-Gass Syndrome** when it occurs following cataract surgery. **Why it is correct:** CME involves the accumulation of fluid in the outer plexiform (Henle’s) and inner nuclear layers of the retina. The classic clinical presentation occurs 2–8 weeks post-cataract surgery. * **Honeycomb appearance:** On slit-lamp biomicroscopy, the fluid-filled microcysts create a characteristic honeycomb pattern. * **Flower-petal appearance:** On Fluorescein Angiography (FFA), leakage from perifoveal capillaries accumulates in the radial arrangement of Henle’s layer, creating a pathognomonic "flower petal" or "stellate" hyperfluorescence. **Why other options are incorrect:** * **Age-related Macular Degeneration (ARMD):** Presents with drusen (Dry) or choroidal neovascularization (Wet). FFA would show a "smoke-stack" or "puddle" pattern in classic CNVM, not a petaloid pattern. * **Central Serous Retinopathy (CSR):** Typically affects younger males and presents with a localized sensory retinal detachment. FFA shows a "smoke-stack" or "ink-blot" appearance. * **Macular Dystrophy:** These are usually bilateral, genetic conditions (e.g., Best’s disease) presenting at a much younger age with specific patterns like an "egg-yolk" lesion. **NEET-PG High-Yield Pearls:** * **Most common cause of decreased vision after uncomplicated cataract surgery:** CME (Irvine-Gass Syndrome). * **Gold Standard Investigation:** Optical Coherence Tomography (OCT) – shows intraretinal cystic spaces. * **Prophylaxis/Treatment:** Topical NSAIDs (e.g., Nepafenac or Ketorolac) and Corticosteroids. * **Risk Factors:** Posterior capsular rupture, vitreous loss, diabetes, and uveitis.

Q: Radiation-induced cataract is classified as which type?

Posterior subcapsular cataract. **Explanation:** **Radiation-induced cataract** typically presents as a **Posterior Subcapsular Cataract (PSC)**. The lens is one of the most radiosensitive tissues in the body. When exposed to ionizing radiation (X-rays, gamma rays), the germinal epithelium at the lens equator is damaged. These damaged cells migrate posteriorly toward the posterior pole, where they fail to differentiate into normal lens fibers and instead form opacities under the posterior capsule. **Analysis of Options:** * **A. Shield cataract:** This is a characteristic dense, plaque-like anterior subcapsular opacity seen in patients with **Atopic Dermatitis** (Atopic Cataract). * **B. Anterior polar cataract:** These are usually **congenital** and often associated with persistent pupillary membranes or intrauterine inflammation. * **D. Alport syndrome:** This genetic condition is classically associated with **Anterior Lenticonus** (a cone-shaped protrusion of the lens) rather than a specific radiation-induced morphology. **High-Yield Clinical Pearls for NEET-PG:** * **Infrared Radiation:** Causes "Glass-blower’s cataract" or "True Exfoliation" of the anterior capsule. * **Steroid-induced Cataract:** Also presents as **Posterior Subcapsular Cataract (PSC)**. * **Electric Shock:** Typically results in **Anterior Subcapsular** opacities. * **Sunflower Cataract:** Seen in **Wilson’s Disease** (Copper deposition). * **Snowflake Cataract:** Seen in **Diabetes Mellitus**. * **Christmas Tree Cataract:** Seen in **Myotonic Dystrophy**.

Q: Complete unilateral congenital cataract should preferably be operated:

Within a few weeks of birth. **Explanation:** The timing of surgery in congenital cataracts is critical to prevent **stimulus-deprivation amblyopia**. In a complete unilateral cataract, the brain receives no visual input from the affected eye, leading to rapid and permanent cortical suppression. **Why Option A is Correct:** The "critical period" for visual development is most sensitive during the first few months of life. For **unilateral** cases, surgery is ideally performed **within 4–6 weeks of birth**. Delaying surgery beyond this window leads to irreversible amblyopia and sensory nystagmus, resulting in poor visual prognosis even if the surgery is technically successful later. **Why Other Options are Incorrect:** * **Option B (6 months):** By this age, the critical period for establishing binocularity is significantly compromised. While bilateral cataracts can sometimes wait slightly longer (up to 10 weeks), 6 months is too late for a unilateral case. * **Options C & D (2 and 5 years):** Operating at these ages is considered "late." The eye will have already developed dense amblyopia, and the surgery would be primarily for cosmetic purposes rather than functional vision. **Clinical Pearls for NEET-PG:** * **Bilateral Complete Cataracts:** Should be operated on within **8–10 weeks** of birth. * **IOL Implantation:** Generally avoided in infants <6 months due to changing axial length and high inflammatory response; the child is managed with aphakic glasses or contact lenses initially. * **Most Common Cause:** Most unilateral congenital cataracts are sporadic (idiopathic), while bilateral cases are often hereditary (Autosomal Dominant) or associated with metabolic disorders (e.g., Galactosemia). * **Visual Rehabilitation:** Surgery is only the first step; aggressive patching of the "good" eye is mandatory post-operatively to treat amblyopia.

Q: Bilateral inferior subluxation of the lens is typically seen in which of the following conditions?

Homocystinuria. **Explanation:** The correct answer is **Homocystinuria**. Ectopia lentis (lens subluxation) is a hallmark of several systemic disorders, and the direction of displacement is a high-yield clinical differentiator in NEET-PG. **1. Why Homocystinuria is correct:** Homocystinuria is an autosomal recessive metabolic disorder caused by a deficiency of the enzyme **cystathionine beta-synthase**. This leads to an accumulation of homocysteine, which interferes with the cross-linking of fibrillin in the zonular fibers. The zonules become brittle and disintegrate, typically resulting in a **downward and inward (inferior/inferonasal)** subluxation. A key clinical feature is that the zonules are often absent or broken, and accommodation is lost. **2. Why the other options are incorrect:** * **Marfan Syndrome:** This is the most common cause of heritable ectopia lentis. However, the subluxation is typically **upward and outward (superotemporal)**. The zonules usually remain intact (though stretched). * **Hyperinsulinemia:** This is not associated with lens subluxation. It is more commonly linked to refractive changes or metabolic cataracts. * **Ocular Trauma:** While trauma is the **most common overall cause** of lens subluxation, it is usually unilateral and the direction depends on the point of impact rather than a systemic pattern. **High-Yield Clinical Pearls for NEET-PG:** * **Marfan vs. Homocystinuria:** Remember **"M"** for Marfan = **"More"** (Upward); **"H"** for Homocystinuria = **"Humble"** (Downward). * **Inheritance:** Marfan is Autosomal Dominant; Homocystinuria is Autosomal Recessive. * **Systemic Risk:** Patients with Homocystinuria have a high risk of **thromboembolic episodes**, especially during general anesthesia. * **Other causes of Inferior Subluxation:** Weill-Marchesani syndrome (though lenses are typically small and spherical—microspherophakia).

Q: Which morphological type of cataract is most visually handicapping?

Posterior subcapsular. **Explanation:** The correct answer is **Posterior Subcapsular Cataract (PSC)**. **1. Why it is the most visually handicapping:** The visual impact of a cataract depends on its proximity to the eye’s nodal point (the optical center). PSC is located at the posterior pole of the lens, directly in the path of converging light rays. Because it lies so close to the nodal point, even a small opacity can cause significant visual distortion. Furthermore, PSC causes **glare** and severe reduction in near vision. This is exacerbated by **miosis** (pupillary constriction) during reading or in bright light, which forces light to pass through the central opacity, further degrading the image. **2. Why other options are incorrect:** * **Cortical Cataract:** These typically present as "cuneiform" (wedge-shaped) opacities in the periphery. They only affect vision when they extend into the pupillary axis. * **Nuclear Cataract:** This involves gradual sclerosis of the lens nucleus. While it causes a "second sight" phenomenon (myopic shift), it progresses slowly and allows for relatively better vision in bright light compared to PSC. * **Zonular (Lamellar) Cataract:** This is a congenital cataract affecting a specific shell of the lens. While it affects vision, it is usually static and less disruptive to functional adult vision than the central, axial opacity of PSC. **Clinical Pearls for NEET-PG:** * **Steroid use:** PSC is the classic type of cataract associated with prolonged systemic or topical corticosteroid therapy. * **Diabetes:** While cortical cataracts are common in diabetics, PSC is also frequently seen. * **Symptoms:** Patients with PSC characteristically complain of **day blindness (Hemeralopia)** and difficulty reading, while patients with nuclear cataracts often experience **night blindness (Nyctalopia)**.

Question 1

Complicated cataract is associated with which of the following conditions?

Accepted Answer

All of the above

Answer

Uveitis

Answer

Retinitis pigmentosa

Answer

Degenerative myopia

Question 2

In complicated cataract, opacity develops in which part of the lens?

Accepted Answer

Posterior subcapsular

Answer

Anterior capsule

Answer

Nucleus

Answer

Cortical

Question 3

A 70-year-old man presents with deterioration of vision 3 weeks after cataract extraction and intraocular lens implantation. Slit lamp examination shows honeycomb maculopathy and Fluorescein angiography shows 'flower petal' hyperfluorescence. What is the most likely diagnosis?

Accepted Answer

Cystoid macular edema

Answer

Age-related macular degeneration

Answer

Central serous retinopathy

Answer

Macular dystrophy

Question 4

Which of the following statements is NOT true about the lens?

Accepted Answer

The posterior epithelium in postnatal life is made up of cuboidal epithelium.

Answer

The pre-equatorial part of the lens capsule is the thickest, measuring 22-23 μm.

Answer

The anterior epithelium is composed of a single layer of cuboidal cells.

Answer

Relative dehydration in the cortex is due to the action of the Na+-K+ ATPase pump.

Question 5

Radiation-induced cataract is classified as which type?

Accepted Answer

Posterior subcapsular cataract

Answer

Shield cataract

Answer

Anterior polar cataract

Answer

Alport syndrome

Question 6

Complete unilateral congenital cataract should preferably be operated:

Accepted Answer

Within a few weeks of birth

Answer

At the age of 6 months

Answer

At the age of 2 years

Answer

At the age of 5 years

Question 7

Presbyopia occurs as a result of the following except?

Accepted Answer

Reduced anterior displacement of the lens during accommodation

Answer

Loss of elasticity of the capsule

Answer

Sclerosis of fibres within the lens

Answer

Reduced contraction of the ciliary muscle

Question 8

Bilateral inferior subluxation of the lens is typically seen in which of the following conditions?

Accepted Answer

Homocystinuria

Answer

Marfan syndrome

Answer

Hyperinsulinemia

Answer

Ocular trauma

Question 9

The epithelium is absent in the lens on which surface?

Accepted Answer

Posterior surface

Answer

Anterior surface

Answer

Anterior pole

Answer

At zonular attachment

Question 10

Which morphological type of cataract is most visually handicapping?

Accepted Answer

Posterior subcapsular

Answer

Cortical

Answer

Nuclear

Answer

Zonular

Diseases of the Lens — MCQs

Diseases of the Lens — MCQs

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