Diseases of the Lens — MCQs

Diseases of the Lens Indian Medical PG Practice Questions and MCQs

Question 261: A 65-year-old male presents with difficulty reading fine print and seeing objects at a distance. Examination reveals a myopic shift in both eyes. What is the most likely cause?

A. Senile cataract (Correct Answer)
B. Diabetic retinopathy
C. Macular degeneration
D. Primary open-angle glaucoma

Explanation: ***Senile cataract (Nuclear sclerotic type)*** - A **myopic shift** (nearsightedness) is a classic and early symptom of **nuclear sclerotic cataracts**, as the increasing density of the lens nucleus changes its refractive index. - This phenomenon is sometimes called **"second sight"** because elderly patients may temporarily find they can read without glasses before the cataract progresses. - Difficulty with both **near vision** (reading fine print) and **distance vision** occurs as the lens opacifies, leading to reduced visual acuity. *Diabetic retinopathy* - This condition primarily affects the **retinal blood vessels**, leading to vision loss through macular edema or hemorrhage, not a myopic shift. - While vision can be impaired, it doesn't typically cause a refractive change like a myopic shift. *Macular degeneration* - **Age-related macular degeneration** causes central vision loss or distortion due to damage to the macula. - It does not cause a myopic shift; rather, it often leads to **metamorphopsia** (straight lines appearing wavy) and blurred central vision. *Primary open-angle glaucoma* - This condition is characterized by **optic nerve damage** and visual field loss, often starting peripherally. - It does not cause a myopic shift, and early stages are often **asymptomatic** until significant peripheral vision is lost.

Question 262: What is the most common identifiable cause of congenital cataracts?

A. Genetic mutations (Correct Answer)
B. Intrauterine infections
C. Metabolic disorders
D. Trauma

Explanation: ***Genetic mutations*** - **Genetic mutations**, including those in genes like *GJA8* (Cx50), *GJA3* (Cx46), and *CRYAA*, are the most common identifiable cause, accounting for a significant portion of isolated and syndromic cases. - Many cases are **autosomal dominant**, indicating a strong heritable component, though recessive and X-linked patterns also occur. *Intrauterine infections* - While intrauterine infections like **TORCH syndrome** (Toxoplasmosis, Others [syphilis, varicella-zoster, parvovirus B19], Rubella, Cytomegalovirus, Herpes simplex) can cause congenital cataracts, they are not the most common identifiable cause overall. - These infections often present with other systemic manifestations, such as **microcephaly**, **hepatosplenomegaly**, or **hearing loss**, in addition to cataracts. *Metabolic disorders* - **Metabolic disorders** such as **galactosemia** and **Lowe syndrome** can lead to congenital cataracts but represent a smaller proportion of identifiable causes compared to genetic mutations. - These conditions are usually associated with other systemic metabolic derangements and require specific diagnostic testing. *Trauma* - **Trauma** (e.g., birth injury) is a rare cause of congenital cataracts and is typically identifiable by a clear history of injury and often unilateral presentation. - Traumatic cataracts are usually distinctly morphological and may be associated with other signs of birth trauma.

Question 263: A 50-year-old female presents with progressive blurring of vision and difficulty with near tasks. Examination reveals posterior subcapsular cataracts. What is the treatment of choice?

A. Observation
B. Topical steroids
C. Laser capsulotomy
D. Surgical extraction (Correct Answer)

Explanation: ***Surgical extraction*** - **Cataract surgery** involves removing the clouded natural lens and replacing it with an **artificial intraocular lens**, which is the definitive treatment for symptomatic cataracts. - This procedure directly addresses the cause of progressive blurring of vision and difficulty with near tasks caused by **posterior subcapsular cataracts**. *Observation* - **Observation** is only appropriate for **mild cataracts** that do not significantly impact vision or daily activities. - Given the patient's "progressive blurring of vision" and "difficulty with near tasks," the cataract is likely **symptomatic** and requires intervention. *Topical steroids* - **Topical steroids** are used to treat ocular inflammation and are not effective in resolving **cataract formation** or improving vision. - Steroids can, in fact, cause or worsen certain types of cataracts, such as **posterior subcapsular cataracts**. *Laser capsulotomy* - **Laser capsulotomy** (specifically YAG laser posterior capsulotomy) is a procedure used to treat **posterior capsule opacification (PCO)**, a common complication *after* cataract surgery. - It does not treat the primary cataract and is not indicated as an initial treatment for **posterior subcapsular cataracts**.

Question 264: Sunflower cataract is caused by

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

Explanation: ***Wilson's disease*** - **Wilson's disease** (hepatolenticular degeneration) is a genetic disorder of copper metabolism causing copper deposition in various tissues - Copper deposition in the **lens capsule** (specifically beneath the anterior lens capsule) creates a characteristic **sunflower cataract** - The cataract shows **multicolored, petal-shaped deposits** radiating from the center, resembling a sunflower - Associated with **Kayser-Fleischer rings** in the cornea (copper deposition in Descemet's membrane) *Diabetes* - Diabetes causes **snowflake cataracts** (cortical opacities) and accelerates age-related cataract formation - The lens changes result from osmotic stress due to sorbitol accumulation from elevated glucose - Does not cause the characteristic copper deposition pattern seen in sunflower cataracts *Atopic dermatitis* - Associated with **anterior subcapsular cataracts** (shield-shaped) due to chronic inflammation - May be exacerbated by topical or systemic corticosteroid use - Does not involve copper deposition or create the sunflower pattern *Chalcosis* - Caused by **intraocular copper-containing foreign body** (usually from penetrating trauma) - Creates a **greenish-brown discoloration** of ocular tissues including lens, iris, and retina - While involving copper, it results from direct foreign body deposition, not systemic copper metabolism disorder - Presents differently from the organized sunflower pattern of Wilson's disease

Question 265: Painful eye movement is a feature of :

A. Iridocyclitis (Correct Answer)
B. Papilledema
C. Corneal ulcer
D. Vernal catarrh

Explanation: ***Iridocyclitis*** - **Inflammation of the iris and ciliary body** causes pain during eye movement due to irritation of the surrounding sensitive structures and muscle spasms. - The ciliary body contains muscles that control lens accommodation, and their inflammation makes eye movements particularly painful. *Papilledema* - This condition involves **swelling of the optic disc** due to increased intracranial pressure. - It usually presents with visual disturbances and headaches but **typically does not cause pain with eye movement**. *Corneal ulcer* - A **corneal ulcer** is an open sore on the cornea, causing severe eye pain, foreign body sensation, and photophobia. - While painful, the pain is primarily localized to the anterior surface of the eye and **does not typically worsen significantly with eye movement**. *Vernal catarrh* - This is a form of severe **allergic conjunctivitis**, causing intense itching, tearing, and mucous discharge. - Although it causes discomfort, a distinct feature of **painful eye movement is not characteristic** of vernal catarrh.

Question 266: Hemeralopia is associated with which of the following conditions?

A. Retinitis pigmentosa
B. Diabetic retinopathy
C. Usher syndrome
D. Subcapsular cataract (Correct Answer)

Explanation: ***Subcapsular cataract*** - Hemeralopia, or **day blindness**, is characterized by better vision in dim light than in bright light, which is a classic symptom of a **posterior subcapsular cataract**. - This type of cataract forms at the back of the lens and is particularly disruptive to vision in bright conditions due to pupil constriction, concentrating light through the densest part of the opacity. - The central location of posterior subcapsular opacities directly interferes with vision in bright light when the pupil constricts. *Retinitis pigmentosa* - This is a hereditary retinal dystrophy that causes progressive peripheral vision loss and **nyctalopia (night blindness)**, which is the opposite of hemeralopia. - Patients have difficulty seeing in dim light due to rod photoreceptor degeneration. - Classic triad includes night blindness, peripheral visual field loss, and bone spicule pigmentation on fundoscopy. *Diabetic retinopathy* - This condition involves damage to the blood vessels of the retina and can lead to blurred vision, floaters, and even blindness, but it does not specifically cause **hemeralopia**. - Its effects on vision are primarily due to retinal ischemia, hemorrhage, macular edema, and neovascularization. *Usher syndrome* - This is a genetic condition that causes both hearing loss and progressive vision loss due to **retinitis pigmentosa**, which manifests as **nyctalopia (night blindness)** in its early stages. - It does not cause hemeralopia; rather, it impairs vision in low light conditions.

Question 267: A 65-year-old male presents with blurred vision and a history of cataract surgery. Upon examination, fluffy white deposits are noted on the anterior lens capsule. What is the most likely diagnosis?

A. Intraocular foreign body
B. Pseudoexfoliation syndrome (Correct Answer)
C. Ocular trauma
D. Vossius ring

Explanation: ***Pseudoexfoliation syndrome*** - The description of **fluffy white deposits on the anterior lens capsule** in an older patient with blurred vision and a history of cataract surgery is highly characteristic of **pseudoexfoliation syndrome**. - This condition is caused by the abnormal production and accumulation of an **extracellular fibrillar material**, which can also affect the iris, ciliary body, and trabecular meshwork, potentially leading to **glaucoma** and lens subluxation. *Intraocular foreign body* - An intraocular foreign body would typically present with a history of **trauma** and might be visible as a distinct object, rather than diffuse fluffy deposits. - While it can cause inflammation and vision changes, its appearance is not consistent with the described findings. *Ocular trauma* - Ocular trauma would typically have an associated history of injury and could present with various signs like hyphema, iritis, or retinal detachment, but not specifically this type of **fluffy white deposit** on the lens. - While it can lead to vision issues, the specific clinical findings do not point towards acute or chronic sequelae of trauma as the primary diagnosis. *Vossius ring* - A **Vossius ring** is a deposition of iris pigment on the anterior lens capsule, forming a circular ring corresponding to the pupil margin at the time of blunt trauma. - It would appear as a **pigmented ring**, not fluffy white deposits, and is directly linked to a history of blunt trauma.

Question 268: Non foldable lens is made of?

A. Acrylic
B. PMMA (Correct Answer)
C. Hydrogel
D. Silicone

Explanation: ***PMMA*** - **Polymethylmethacrylate (PMMA)** is a rigid, non-foldable material historically used for **intraocular lenses (IOLs)**. - Due to its rigidity, PMMA IOLs require a **larger incision** for implantation, which can lead to astigmatism and slower recovery. *Silicone* - **Silicone** is a flexible, foldable material commonly used for modern IOLs, allowing for **smaller incisions**. - It has excellent **elastic properties** but may be associated with certain risks in eyes with silicone oil. *Acrylic* - **Acrylic** (both hydrophobic and hydrophilic) is a popular material for foldable IOLs, known for its **biocompatibility** and ability to be inserted through small incisions. - It is currently the most widely used material due to its **foldable nature** and good optical qualities. *Hydrogel* - **Hydrogel** is a type of hydrophilic acrylic material, characterized by its **high water content** and flexibility. - While foldable, hydrogel IOLs are less commonly used than other acrylic types, partly due to some concerns about long-term clarity or calcification in certain formulations.

Question 269: What is the type of cataract associated with Galactosemia?

A. Oil drop (Correct Answer)
B. Snowflake cataract
C. Blue dot cataract
D. Polychromatic lustre cataract

Explanation: ***Oil drop*** - This characteristic appearance is caused by the accumulation of **galactitol** in the lens, leading to changes in refractive index. - The "oil drop" cataract is a classic sign of **galactosemia**, often appearing as an early manifestation of the disease. *Snowflake cataract* - This type of cataract is more commonly associated with **diabetes mellitus** rather than galactosemia. - It presents as **fluffy white opacities** that can lead to rapid vision loss. *Blue dot cataract* - This is typically a **congenital stationary cataract** with small, bluish opacities in the peripheral lens. - It is usually **benign** and non-progressive, and not specifically linked to metabolic disorders like galactosemia. *Polychromatic lustre cataract* - This describes the varied, iridescent colors seen in certain types of cataracts, often associated with **complicated cataracts** or those near the lens sutures. - It does not specifically refer to the unique "oil drop" appearance of galactosemic cataracts.

Question 270: D Shaped pupil is seen in which condition?

A. Anterior synechiae
B. Anterior Uveitis
C. Iridodialysis (Correct Answer)
D. Iridodonesis

Explanation: ***Iridodialysis*** - **Iridodialysis** is a disinsertion or separation of the iris from its root at the ciliary body. - This separation creates a D-shaped or keyhole pupil, as the detached portion of the iris no longer contributes to the circular pupillary margin. *Anterior Uveitis* - **Anterior uveitis** is inflammation of the iris and ciliary body, primarily causing miosis (constricted pupil), not a D-shaped pupil. - It can lead to posterior synechiae, resulting in an irregular, but not typically D-shaped, pupil. *Anterior synechiae* - **Anterior synechiae** involve adhesions between the iris and the corneal endothelium or trabecular meshwork. - While they can cause an irregular pupil shape, they typically pull the iris towards the cornea rather than creating a D-shape from iris root disinsertion. *Iridodonesis* - **Iridodonesis** refers to tremors or wobbling of the iris, often seen in cases of aphakia or subluxated lenses, due to lack of support. - It describes a movement disorder of the iris rather than an abnormal, fixed pupil shape like a D-shaped pupil.

Practice by Chapter

Lens Anatomy and Physiology

Practice Questions

Age-Related Cataract

Practice Questions

Congenital and Developmental Cataracts

Practice Questions

Traumatic Cataract

Practice Questions

Metabolic Cataracts

Practice Questions

Drug-Induced Cataracts

Practice Questions

Cataract Surgery Techniques

Practice Questions

Intraocular Lens Implants

Practice Questions

Complications of Cataract Surgery

Practice Questions

Posterior Capsular Opacification

Practice Questions

Lens Subluxation and Dislocation

Practice Questions

Specialty IOLs

Practice Questions

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