Diseases of the Lens Practice Questions

Q: In aphakia, which Purkinje fibres are absent?

3 and 4. **Explanation:** The Purkinje-Sanson images are reflections produced by the different refractive surfaces of the eye. To understand why images 3 and 4 are absent in aphakia, we must look at the anatomical structures responsible for each reflection: 1. **Purkinje Image 1:** Formed by the anterior surface of the **cornea**. 2. **Purkinje Image 2:** Formed by the posterior surface of the **cornea**. 3. **Purkinje Image 3:** Formed by the anterior surface of the **crystalline lens**. 4. **Purkinje Image 4:** Formed by the posterior surface of the **crystalline lens**. **Aphakia** is defined as the clinical absence of the crystalline lens. Since images 3 and 4 are generated specifically by the surfaces of the lens, they cannot be formed if the lens is missing. Therefore, **Option D (3 and 4)** is the correct answer. **Analysis of Incorrect Options:** * **Options A, B, and C:** These are incorrect because they include images 1 or 2. Images 1 and 2 are corneal reflections; as long as the cornea is intact, these images will persist regardless of the status of the lens. **High-Yield Clinical Pearls for NEET-PG:** * **Image Characteristics:** Images 1, 2, and 3 are **erect** (formed by convex surfaces acting as mirrors). Image 4 is **inverted** (formed by the concave posterior lens surface). * **Brightness/Size:** Image 1 is the brightest. Image 3 is the largest. * **Pseudophakia:** In a patient with an Intraocular Lens (IOL), all four images are present, but they may appear sharper or have different intensities compared to a natural lens. * **Sanson’s Test:** This clinical test uses these reflections to diagnose the presence of a lens or the type of cataract. In a mature cataract, image 4 is typically lost because light cannot penetrate to the posterior surface.

Q: What is the diagnosis in a patient who presented with sudden painful vision impairment after vigorous exercise?

Dislocation of the lens. **Explanation:** The correct answer is **Dislocation of the lens (C)**. In the context of NEET-PG, the combination of **vigorous exercise** (or minor trauma) and **sudden painful vision loss** is a classic presentation for lens subluxation or dislocation. When the lens dislocates into the anterior chamber, it can cause an acute rise in intraocular pressure (secondary angle-closure glaucoma) due to pupillary block, leading to sudden pain and blurred vision. This is particularly common in patients with underlying zonular weakness (e.g., Marfan syndrome or Homocystinuria). **Analysis of Incorrect Options:** * **A. Central Retinal Artery Occlusion (CRAO):** While it causes sudden vision loss, it is characteristically **painless**. The classic finding is a "cherry-red spot" on the macula. * **B. Corneal Ulcer:** This presents with pain and redness, but the onset is typically gradual (over days) rather than sudden following physical exertion, and it is usually associated with discharge or a visible white infiltrate. * **D. Episcleritis:** This causes localized redness and mild discomfort, but it does **not** cause significant vision impairment. **Clinical Pearls for NEET-PG:** * **Ectopia Lentis:** The most common cause of non-traumatic lens dislocation is **Marfan syndrome** (typically bilateral, superior-temporal displacement). * **Homocystinuria:** Lens dislocation is typically **inferior-nasal** and associated with intellectual disability and prothrombotic states. * **Phacolytic vs. Phacomorphic Glaucoma:** Remember that a dislocated lens can lead to **Phacomorphic glaucoma** (lens-induced angle closure), a high-yield surgical emergency. * **Iridodonesis:** Tremulousness of the iris is a key clinical sign of a subluxated or absent lens.

Q: Secondary cataract is an opacity of which of the following?

The lens after extracapsular extraction. **Explanation:** **Secondary Cataract**, also known as **After-Cataract**, refers to the opacification that develops in the remaining lens components following an **Extracapsular Cataract Extraction (ECCE)** or Phacoemulsification. In these surgeries, the posterior capsule and parts of the anterior capsule are left intact to support the Intraocular Lens (IOL). The opacity arises due to the proliferation and migration of residual lens epithelial cells (LECs) across the posterior capsule. The most common clinical presentation is **Posterior Capsular Opacification (PCO)**. **Analysis of Options:** * **Option A (Correct):** As explained, it occurs post-ECCE due to the proliferation of residual subcapsular epithelium. * **Option B & C (Incorrect):** Nd:YAG laser iridotomy and peripheral iridectomy are procedures performed on the **iris** (usually for glaucoma). While intraocular surgery can technically accelerate cataract formation, "Secondary Cataract" is a specific pathological term reserved for post-ECCE opacification. * **Option D (Incorrect):** Opacity due to nutritional deficiency or metabolic disorders is classified under **Complicated Cataract** or metabolic cataract, not secondary cataract. **High-Yield Clinical Pearls for NEET-PG:** * **Morphological Types:** 1. **Elschnig’s Pearls:** Round, vacuolated cells (common in children). 2. **Soemmering’s Ring:** A ring-shaped opacity formed when residual cortex is trapped between the two layers of the capsule. * **Treatment of Choice:** **Nd:YAG laser capsulotomy** (painless, outpatient procedure to create a central opening in the opacified capsule). * **Prevention:** Use of IOLs with **square-edge designs** and thorough cortical washing during surgery significantly reduces PCO incidence.

Q: Which of the following types of cataract is most commonly associated with aging?

Nuclear cataract. **Explanation:** **Nuclear Cataract** is the most common type of age-related (senile) cataract. It occurs due to the progressive intensification of the normal aging process of the lens. As we age, the lens fibers become increasingly compressed and dehydrated at the center (nucleus), leading to **nuclear sclerosis**. This is characterized by the deposition of yellow-brown pigment (urochrome), which increases the refractive index of the lens, often causing a "myopic shift" or "second sight" in elderly patients. **Analysis of Incorrect Options:** * **B. Intumescent cataract:** This is a stage of cataract progression (usually cortical) where the lens becomes swollen due to the osmotic imbibition of water. It is not a primary type associated with aging but rather a complication of the immature stage. * **C. Morgagnian cataract:** This represents a hypermature stage where the cortex liquefies, allowing the heavy, brownish nucleus to settle at the bottom of the capsular bag. This is an advanced stage, not the most common presentation. * **D. Posterior subcapsular cataract (PSC):** While it can occur with age, it is more classically associated with **steroid use**, diabetes mellitus, or ionizing radiation. It causes significant glare and vision loss in bright light. **High-Yield Clinical Pearls for NEET-PG:** * **Second Sight:** A hallmark of nuclear cataract where the myopic shift allows elderly patients to read without glasses again. * **Cupuliform Cataract:** Another name for Posterior Subcapsular Cataract. * **Grading:** Nuclear cataracts are graded based on color (e.g., *Cataracta Brunescens* for brown, *Cataracta Nigra* for black). * **Most common cause of blindness in India:** Cataract (specifically senile).

Q: Rider's cataract is seen in which of the following types of cataracts?

Zonular cataract. **Explanation:** **Zonular (Lamellar) cataract** is the most common type of congenital cataract. It is characterized by opacity involving a specific "zone" or layer of the lens fibers (usually the fetal nucleus), while the embryonic nucleus and the cortex remain clear. The hallmark feature of this condition is **"Riders."** These are linear, U-shaped opacities that extend from the main zone of opacity into the clear cortex, straddling the equator like a rider on a horse. This occurs because the lens fibers formed during the period of metabolic insult become opaque, while those formed before and after remain transparent. **Analysis of Incorrect Options:** * **Blue dot cataract (Punctate cataract):** These are the most common congenital cataracts but are usually stationary and asymptomatic. They appear as small, bluish, rounded opacities scattered throughout the lens. * **Anterior capsular cataract:** These are small, central, white opacities on the anterior lens capsule, often associated with persistent pupillary membranes or intrauterine inflammation. * **Coronary cataract:** This is a form of senile or developmental cataract where club-shaped opacities are arranged in a ring (like a crown) in the peripheral deep cortex, often hidden by the iris. **Clinical Pearls for NEET-PG:** * **Etiology:** Zonular cataracts are frequently associated with **Vitamin D deficiency (Hypocalcemia)** during infancy or maternal infections. * **Visual Impact:** They are usually bilateral and often cause significant visual impairment, frequently requiring surgical intervention. * **Morphology:** Always look for the keyword "linear opacities straddling the equator" to identify Riders.

Q: A 60-year-old male presents with coloured halos. On Fincham's test, the halos split and then reunite. The most probable diagnosis is?

Senile immature cataract. **Explanation:** The presence of colored halos is a classic symptom in ophthalmology, typically caused by the diffraction of light. The **Fincham’s Test** is the definitive clinical maneuver used to differentiate the cause of these halos. **1. Why Senile Immature Cataract is correct:** In an immature cataract, the halos are produced by the **radial arrangement of lens fibers**, which act as a diffraction grating. When a stenopeic slit is moved across the pupil (Fincham’s Test), the halos **split and then reunite**. This "splitting" is pathognomonic for lenticular halos (cataract). **2. Why the other options are incorrect:** * **Acute Congestive Glaucoma:** Halos are caused by **corneal edema** (fluid droplets in the epithelium). Since the edema is uniform and lacks a radial structure, the halos **do not split** during Fincham’s test; they simply disappear or diminish in intensity. * **Open Angle Glaucoma:** This condition is usually asymptomatic in early stages and does not typically present with colored halos unless the intraocular pressure is acutely very high. * **Mucopurulent Conjunctivitis:** Halos here are caused by **mucus flakes** on the corneal surface. These halos are transient and **disappear after blinking** or washing the eyes. **Clinical Pearls for NEET-PG:** * **Glaucomatous Halos:** The blue-violet ring is innermost, and the red ring is outermost. * **Fincham’s Test Result:** * *Splitting:* Lenticular (Cataract) * *No Splitting:* Corneal (Glaucoma) * **Differential Diagnosis of Halos:** Remember the "3 C's": **C**ataract, **C**orneal Edema (Glaucoma), and **C**onjunctivitis (Mucus). * **Stenopeic Slit:** This is the tool used to perform Fincham's test.

Q: Which of the following is true about lens epithelium?

Is deposited as lens fibers. The lens epithelium is a single layer of cuboidal cells located just beneath the anterior lens capsule. Understanding its dynamics is crucial for NEET-PG. ### **Explanation of the Correct Option** **B. Is deposited as lens fibers:** The lens epithelium is metabolically active only in the anterior and equatorial regions. At the **equator (germinal zone)**, these epithelial cells undergo continuous mitosis, elongate, and differentiate into **secondary lens fibers**. These new fibers are deposited layer-upon-layer over the pre-existing ones throughout life. This unique process makes the lens the only organ that never sheds its cells, leading to the increasing density of the lens nucleus with age. ### **Analysis of Incorrect Options** * **A. Contains polygonal cells:** The anterior lens epithelium consists of a single layer of **cuboidal cells**, not polygonal cells. These cells are responsible for the metabolic transport and synthesis of crystallins. * **C. Remains dehydrated:** While the lens maintains a relatively low water content (approx. 66%) to ensure transparency, it is not "dehydrated." It maintains a **state of relative deturgescence** through the active Na+/K+ ATPase pump located primarily in the lens epithelium. ### **High-Yield Clinical Pearls for NEET-PG** * **Posterior Capsule:** There is **no posterior epithelium** in the adult lens (it is used up during embryonic development to form primary lens fibers). This is why the posterior capsule is the thinnest part of the lens. * **Vossius Ring:** A circular ring of pigment on the anterior lens capsule following blunt trauma, corresponding to the pupillary margin. * **Epicapsular Stars:** Remnants of the tunica vasculosa lentis found on the anterior lens surface (congenital anomaly). * **Cataract Pathogenesis:** Abnormal proliferation and migration of epithelial cells toward the posterior pole lead to **Posterior Subcapsular Cataract (PSC)**.

Q: What is the surgery of choice for congenital cataract?

Extracapsular cataract extraction (ECCE). **Explanation:** The management of congenital cataract focuses on providing a clear visual axis to prevent irreversible amblyopia. **Why ECCE is the Correct Answer:** **Extracapsular Cataract Extraction (ECCE)**, specifically via **Lens Aspiration**, is the gold standard. In children, the lens matter is soft and can be easily aspirated. Modern pediatric cataract surgery involves ECCE with **Primary Posterior Capsulotomy (PPC)** and **Anterior Vitrectomy**. This is crucial because, in children, the posterior capsule opacifies (PCO) almost 100% of the time if left intact. For children >2 years of age, ECCE is combined with Posterior Chamber Intraocular Lens (PCIOL) implantation. **Analysis of Incorrect Options:** * **Intracapsular Cataract Extraction (ICCE):** This is **contraindicated** in children. The vitreous is strongly adherent to the posterior lens capsule (Wieger’s ligament). Removing the entire lens capsule would result in massive vitreous loss and high risk of retinal detachment. * **Needling:** An obsolete technique where a needle was used to puncture the capsule to allow aqueous to dissolve the lens. It often led to severe inflammation (phacoanaphylactic uveitis) and secondary glaucoma. * **Discission:** Similar to needling, it involves incising the anterior capsule. While it may be a component of surgery, it is not a complete procedure for cataract removal. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Surgery should be done as early as possible (ideally before 6–8 weeks of age) to prevent stimulus-deprivation amblyopia. * **IOL Calculation:** In infants, the eye is under-corrected (hyperopic target) to account for the "myopic shift" as the eye grows. * **Most common cause:** Idiopathic (overall), but **Galactosemia** is a classic metabolic cause (Oil droplet cataract). * **Rubella:** Characterized by "Pearly white nuclear cataract."

Q: Nuclear cataract is associated with which refractive error?

Index myopia. In nuclear cataracts, the central part of the lens (the nucleus) undergoes progressive sclerosis and opacification. This process increases the **Refractive Index** of the lens nucleus. According to the principles of optics, an increase in the refractive index of the lens increases its total dioptric power, causing light rays to focus in front of the retina. This shift is termed **Index Myopia**. **Explanation of Options:** * **A. Index Myopia (Correct):** The hardening and increased density of the nucleus lead to a higher refractive index, shifting the patient’s refraction toward myopia. * **B. Index Hypermetropia:** This occurs when the refractive index of the lens decreases (e.g., in cortical cataracts due to hydration changes) or when the refractive index of the vitreous increases (e.g., in some diabetic states). * **C & D. Axial Myopia/Hypermetropia:** These refractive errors are determined by the **axial length** of the eyeball (too long or too short, respectively), not by changes in the lens density or refractive index. **Clinical Pearls for NEET-PG:** * **Second Sight (Day-sight):** Patients with nuclear cataracts often experience a temporary improvement in near vision (e.g., being able to read without glasses again) due to the induced index myopia. This is a classic "buzzword" for nuclear cataracts. * **Color Perception:** Nuclear cataracts act as a yellow/brown filter, leading to poor blue-color discrimination (cyanopsia). * **Grading:** Nuclear cataracts are graded based on color (from pale yellow to black/brown, known as *Cataracta Brunescens*). * **Contrast:** While nuclear cataracts cause index myopia, **Cortical cataracts** are more commonly associated with an initial shift toward **Index Hypermetropia** due to a decrease in the refractive index of the cortex.

Q: A 55-year-old male presents with vision of 6/12 in both eyes and complaints of glare at night, particularly while driving. What is the most likely diagnosis?

Opacification of the lens. **Explanation:** The correct answer is **Opacification of the lens (Cataract)**. **1. Why Opacification of the lens is correct:** The hallmark symptom described—**glare (photophobia) at night**, especially from oncoming headlights while driving—is a classic presentation of early cataracts, particularly **posterior subcapsular** or **cortical cataracts**. As the lens becomes opaque, it causes light rays to scatter (diffraction) instead of focusing sharply on the retina. This scattering manifests as glare and halos. A visual acuity of 6/12 in a 55-year-old further supports the diagnosis of age-related lens changes. **2. Why other options are incorrect:** * **Diabetic Retinopathy:** Typically presents with blurred vision, floaters, or sudden vision loss (vitreous hemorrhage). While it affects vision, "glare at night" is not its primary or pathognomonic symptom. * **Age-related Macular Degeneration (ARMD):** Patients usually complain of central vision loss, metamorphopsia (distortion of shapes), or a central scotoma. Peripheral vision and light scattering are generally not the initial complaints. * **Corneal Degeneration:** While some corneal pathologies (like Keratoconus or corneal edema) can cause glare, they are less common in a 55-year-old presenting with bilateral 6/12 vision compared to the high prevalence of cataracts in this age group. **Clinical Pearls for NEET-PG:** * **Cataract Types & Symptoms:** Nuclear cataracts often cause "second sight" (myopic shift), while Posterior Subcapsular Cataracts (PSC) cause significant glare and near-vision impairment. * **Glare Test:** The Brightness Acuity Tester (BAT) is used clinically to evaluate the impact of glare on a patient's functional vision. * **Differential for Glare:** Always consider Cataract, Corneal edema, and status post-refractive surgery (LASIK/PRK).

Question 1

In aphakia, which Purkinje fibres are absent?

Accepted Answer

3 and 4

Answer

1 and 3

Answer

2 and 4

Answer

2 and 3

Question 2

What is the diagnosis in a patient who presented with sudden painful vision impairment after vigorous exercise?

Accepted Answer

Dislocation of the lens

Answer

Central retinal artery occlusion

Answer

Corneal ulcer

Answer

Episcleritis

Question 3

Secondary cataract is an opacity of which of the following?

Accepted Answer

The lens after extracapsular extraction

Answer

The lens after Nd:YAG laser iridotomy

Answer

The lens after peripheral iridectomy

Answer

The lens due to nutritional deficiency

Question 4

Which of the following types of cataract is most commonly associated with aging?

Accepted Answer

Nuclear cataract

Answer

Intumescent cataract

Answer

Morgagnian cataract

Answer

Posterior subcapsular cataract

Question 5

Rider's cataract is seen in which of the following types of cataracts?

Accepted Answer

Zonular cataract

Answer

Blue dot cataract

Answer

Anterior capsular cataract

Answer

Coronary cataract

Question 6

A 60-year-old male presents with coloured halos. On Fincham's test, the halos split and then reunite. The most probable diagnosis is?

Accepted Answer

Senile immature cataract

Answer

Acute congestive glaucoma

Answer

Open angle glaucoma

Answer

Mucopurulent conjunctivitis

Question 7

Which of the following is true about lens epithelium?

Accepted Answer

Is deposited as lens fibers

Answer

Contains polygonal cells

Answer

Remains dehydrated

Answer

None of the above

Question 8

What is the surgery of choice for congenital cataract?

Accepted Answer

Extracapsular cataract extraction (ECCE)

Answer

Intracapsular cataract extraction (ICCE)

Answer

Needling

Answer

Discission

Question 9

Nuclear cataract is associated with which refractive error?

Accepted Answer

Index myopia

Answer

Index hypermetropia

Answer

Axial myopia

Answer

Axial hypermetropia

Question 10

A 55-year-old male presents with vision of 6/12 in both eyes and complaints of glare at night, particularly while driving. What is the most likely diagnosis?

Accepted Answer

Opacification of the lens

Answer

Diabetic retinopathy

Answer

Age-related macular degeneration

Answer

Corneal degeneration

Diseases of the Lens — MCQs

Diseases of the Lens — MCQs

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