Diseases of the Lens — MCQs

Diseases of the Lens Indian Medical PG Practice Questions and MCQs

Question 301: A 60-year-old male presents with colored halos around lights. The most probable diagnosis is

A. Senile immature cataract
B. Acute angle closure glaucoma (Correct Answer)
C. Chronic open angle glaucoma
D. Bacterial conjunctivitis

Explanation: ***Acute angle closure glaucoma*** - **Colored halos (rainbow-colored)** around lights are a classic and pathognomonic symptom of **acute angle closure glaucoma**, caused by corneal edema secondary to elevated intraocular pressure. - The edematous cornea acts as a **prism**, breaking white light into its spectral colors, producing the characteristic rainbow halos. - These colored halos can occur as **prodromal symptoms** before a full acute attack, and may be present even without severe eye pain, especially in subacute or intermittent angle closure. - The patient's age (60 years) fits the typical demographic, as angle closure glaucoma is more common in older adults, hypermetropes, and those with shallow anterior chambers. *Senile immature cataract* - Cataracts typically cause **monochromatic (white) halos** or glare around lights due to light scattering by lens opacities, not the colored/rainbow halos described. - The predominant symptoms of cataracts are **progressive blurred vision**, difficulty with night driving, and glare, rather than colored halos. - While cataracts are common at age 60, the specific symptom of colored halos does not point to this diagnosis. *Chronic open angle glaucoma* - This is typically **asymptomatic** in early stages and presents with gradual **peripheral vision loss** and optic nerve cupping. - Colored halos are not a characteristic feature of chronic open angle glaucoma, as IOP elevation is usually gradual and does not cause significant corneal edema. *Bacterial conjunctivitis* - Presents with **redness, discharge, irritation**, and foreign body sensation due to conjunctival inflammation. - Does not cause visual disturbances like colored halos, as it does not affect the cornea or cause elevated intraocular pressure.

Question 302: Lens subluxation is associated with all of the following conditions except:

A. Congenital syphilis (Correct Answer)
B. Homocystinuria
C. Ehlers-Danlos syndrome
D. Marfan syndrome

Explanation: ***Congenital syphilis*** - While congenital syphilis can cause various ocular manifestations like **interstitial keratitis** and **chorioretinitis**, lens subluxation is not a typical association. - Ocular problems in congenital syphilis are primarily due to **inflammation** rather than connective tissue defects affecting zonular fibers. *Homocystinuria* - **Lens subluxation** (ectopia lentis) is a classic feature of homocystinuria, with the lens typically displaced **inferonasally**. - This condition affects **cystathionine synthase**, leading to accumulation of homocysteine and methionine, causing defective **collagen cross-linking** and **fibrillin** synthesis, which weakens zonular fibers supporting the lens. *Ehlers-Danlos syndrome* - Certain types of Ehlers-Danlos syndrome, particularly **type VI (kyphoscoliotic)**, are associated with **lens subluxation** due to defects in connective tissue. - The syndrome is characterized by **collagen defects**, leading to joint hypermobility, fragile skin, tissue laxity, and weakened ocular zonules. *Marfan syndrome* - **Marfan syndrome** is the most common hereditary cause of lens subluxation, with ectopia lentis occurring in approximately **60-80%** of patients. - The lens typically dislocates **superotemporal** due to mutations in the **FBN1 gene** encoding fibrillin-1, causing weakened zonular fibers. - Other ocular features include myopia, retinal detachment, and increased axial length.

Question 303: What is the most common type of congenital cataract?

A. Polar cataract
B. Coralliform cataract
C. Capsular cataract
D. Lamellar cataract (Correct Answer)

Explanation: ***Lamellar cataract*** - **Lamellar cataracts**, also known as **zonular cataracts**, are the **most common** type of congenital cataract, accounting for approximately 40-50% of all congenital cataracts. - They are characterized by opacities affecting specific layers or lamellae of the lens, forming concentrically around the embryonic nucleus. - They can significantly impair vision depending on their density and size, and often present with a characteristic "riders" appearance on slit-lamp examination. *Polar cataract* - **Polar cataracts** involve the anterior or posterior pole of the lens and are typically small, well-circumscribed opacities. - They are less common than lamellar cataracts and may be stationary or progressive. - Posterior polar cataracts are more visually significant due to their location near the nodal point of the eye. *Capsular cataract* - **Capsular cataracts** involve the outermost layer of the lens, either anterior or posterior capsule, with minimal involvement of the lens cortex itself. - While they can be visually significant, they are less common overall than lamellar cataracts. *Coralliform cataract* - **Coralliform cataracts** are a rare type of congenital cataract characterized by **coral-like opacities** located in the deep cortex and nucleus. - They have a distinct morphology but are not the most frequently encountered congenital cataract.

Question 304: Anterior lenticonus is found in which of the following conditions?

A. Lowe's syndrome
B. Down syndrome
C. Alport syndrome (Correct Answer)
D. Williams syndrome

Explanation: ***Alport syndrome*** - **Anterior lenticonus** is a classic ocular manifestation of **Alport syndrome**, characterized by a conical protrusion of the lens. - It often accompanies **progressive sensorineural hearing loss** and **glomerulonephritis**. *Lowe's syndrome* - Ocular manifestations include **congenital cataracts** and **glaucoma**, but **lenticonus** is not typically associated. - This syndrome also presents with **renal tubular dysfunction** and **intellectual disability**. *Down syndrome* - Common ocular features in **Down syndrome** include **strabismus**, **nystagmus**, and **cataracts**, particularly brushfield spots. - **Lenticonus** is not a characteristic finding in this chromosomal disorder. *Williams syndrome* - Patients with **Williams syndrome** often have an increased risk of **strabismus** and **hyperopia**. - **Anterior lenticonus** is not a recognized feature of this genetic condition, which is primarily characterized by intellectual disability, unique facial features, and cardiovascular abnormalities.

Question 305: In which condition are Elschnig pearls typically observed?

A. Wilson's disease
B. Congenital cataract
C. Complicated cataract
D. Secondary cataract (Correct Answer)

Explanation: ***Secondary cataract*** - **Elschnig pearls** are secondary cataracts characterized by the proliferation and migration of residual epithelial cells on the posterior capsule after **extracapsular cataract extraction**. - These are a common cause of **posterior capsule opacification (PCO)**, which leads to blurred vision following cataract surgery. *Wilson's disease* - This condition is associated with **Kayser-Fleischer rings** in the cornea, which are deposits of copper, not Elschnig pearls. - It is a **genetic disorder** of copper metabolism affecting various organs, including the liver, brain, and eyes. *Complicated cataract* - While complicated cataracts refer to cataracts occurring secondary to other ocular or systemic diseases, the term itself does not specifically describe Elschnig pearls. - Examples include cataracts due to **uveitis** or **diabetes**, which have distinct morphological characteristics. *Congenital cataract* - These cataracts are present at birth or develop shortly thereafter and are due to **genetic factors** or **in utero infections**. - They have various appearances depending on the cause but do not present as Elschnig pearls, which are a postoperative phenomenon.

Question 306: Rosette-shaped cataract is seen in

A. Trauma (Correct Answer)
B. Diabetes mellitus
C. Congenital syphilis
D. Infectious diseases

Explanation: ***Trauma*** - A **rosette-shaped cataract** is highly characteristic of **blunt ocular trauma** and **electric shock/lightning injury**, which cause a stellate or flower-like opacification of the lens. - Blunt trauma can disrupt the arrangement of lens fibers, leading to this distinctive pattern of opacification. - Electric shock causes characteristic **anterior subcapsular rosette cataracts** due to direct energy transfer to the lens. *Diabetes mellitus* - Poorly controlled diabetes can lead to **diabetic cataracts**, which are typically **snowflake cataracts** in younger patients or accelerated **age-related cataracts** (cortical, nuclear sclerotic, or posterior subcapsular). - These do not usually present with a rosette shape. *Congenital syphilis* - Congenital syphilis can cause various ocular manifestations, including **interstitial keratitis** and **salt-and-pepper retinopathy**, but it is not typically associated with rosette-shaped cataracts. - Cataracts in congenital syphilis are rare and not described as such. *Infectious diseases* - While some intraocular infections (e.g., toxoplasmosis, rubella) can contribute to cataract formation, they generally do not produce a **rosette-shaped cataract**. - The appearance of cataracts in infectious diseases is more varied and often associated with inflammation or other specific pathogenic mechanisms.

Question 307: Christmas tree cataract is seen in:

A. Galactosemia
B. Diabetes
C. Myotonic Dystrophy (Correct Answer)
D. Blunt trauma

Explanation: ***Myotonic Dystrophy*** - **Christmas tree cataracts** are characterized by highly iridescent, multi-colored, needle-shaped crystals seen in the lens cortex, a classic ophthalmological feature of **myotonic dystrophy type 1**. - These cataracts often appear in the third to fourth decade of life and can precede other systemic manifestations of the disease. *Diabetes* - Diabetes can cause various types of cataracts, including **snowflake cataracts** (rapidly progressive, typically in younger diabetics) and senile cataracts that progress more quickly, but not specifically Christmas tree cataracts. - Diabetic cataracts are often linked to osmotic stress from sorbitol accumulation in the lens. *Galactosemia* - **Galactosemia** is associated with the formation of an **oil droplet cataract**, which is typically central, symmetrical, and develops in infancy due to the accumulation of galactitol. - This type of cataract is pathognomonic for galactosemia and is distinct from the iridescent crystals of Christmas tree cataracts. *Blunt trauma* - **Blunt trauma** to the eye can lead to various lenticular opacities, such as a **rosette cataract** (petal-shaped opacities) or a **Vossius ring** (pigment on the anterior capsule). - While trauma can induce cataract formation, it does not typically cause the specific "Christmas tree" morphology characterized by iridescent crystals.

Question 308: What is the typical appearance of cataracts associated with diabetes?

A. Sunflower type
B. Breadcrumb type
C. Snowflake appearance (Correct Answer)
D. Polychromatic lustre

Explanation: ***Snowflake appearance*** - Diabetic cataracts, particularly in young patients with poorly controlled diabetes, can rapidly progress and present with a **snowflake appearance** due to diffuse **subcapsular opacities**. - This appearance is characterized by discrete, **white, flaky opacities** that resemble snowflakes, often located in the anterior and posterior subcapsular regions. *Sunflower type* - The sunflower cataract is typically associated with **Wilson's disease**, a genetic disorder of **copper metabolism**. - It results from copper deposits in the lens, forming a pigmented, spoke-like pattern resembling a sunflower. *Breadcrumb type* - The term "breadcrumb type" is not a recognized clinical description for a specific type of cataract. - Cataract classifications usually refer to their morphology (e.g., nuclear, cortical, subcapsular) or associated systemic conditions. *Polychromatic lustre* - A **polychromatic lustre** or iridescence is a feature often seen in **posterior subcapsular cataracts**, which can be associated with various conditions including prolonged corticosteroid use, inflammation, or trauma, but it is not specific to diabetes. - While diabetic cataracts can have a posterior subcapsular component, the term "polychromatic lustre" describes the **refractive properties** rather than the typical opacification pattern seen in rapidly progressing diabetic cataracts.

Question 309: Crystallin protein aggregation and modification are key mechanisms in cataract formation across various species, including humans. Which of the following protein pairs are known to be associated with cataract development through aggregation or cross-linking?

A. γ-crystallin complexes and damaged lens fiber proteins
B. α-crystallin aggregates and β-crystallin aggregates
C. β-crystallin aggregates and γ-crystallin complexes (Correct Answer)
D. β-crystallin aggregates and damaged lens fiber proteins

Explanation: ***β-crystallin aggregates and γ-crystallin complexes*** - **β-crystallins** are major structural proteins in the lens that undergo aggregation and form high molecular weight complexes in age-related and congenital cataracts, leading to light scattering and lens opacification. - **γ-crystallins** are abundant in the lens nucleus and are particularly prone to aggregation, unfolding, and complex formation due to oxidative stress, UV exposure, and post-translational modifications. - This combination represents **two of the three major crystallin families** that directly contribute to cataract formation through protein aggregation and insolubilization. - Both proteins lose their normally soluble structure and form light-scattering aggregates that are hallmarks of cataract pathogenesis. *α-crystallin aggregates and β-crystallin aggregates* - While both α- and β-crystallins do aggregate in cataracts, **α-crystallin** primarily functions as a **molecular chaperone** that prevents aggregation of other proteins. - α-crystallin aggregation typically represents loss of chaperone function rather than being a primary aggregation mechanism. - This option would also be partially correct but is less specific than the combination of β and γ crystallins. *γ-crystallin complexes and damaged lens fiber proteins* - The term **"damaged lens fiber proteins"** is too vague and non-specific for a medical education question. - While γ-crystallins do form complexes, pairing them with this general term doesn't identify a specific protein pair as asked in the question. - Lens fiber proteins include all crystallins, so this doesn't specify which other protein family is involved. *β-crystallin aggregates and damaged lens fiber proteins* - Again, **"damaged lens fiber proteins"** is too general and doesn't specify a particular protein type. - This option fails to identify a specific protein pair involved in cataract formation. - The question specifically asks for protein pairs, requiring identification of both protein types involved.

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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