Diseases of the Retina Practice Questions

Q: Soft exudates (cotton wool spots) are typically found in which layer of the retina?

Nerve fiber layer. **Explanation:** **Cotton wool spots (Soft exudates)** are not true exudates but rather micro-infarcts of the **Nerve Fiber Layer (NFL)**. They occur due to the occlusion of terminal retinal arterioles, leading to axoplasmic stasis (the buildup of axoplasmic material) within the ganglion cell axons. This accumulation appears clinically as fluffy, white, cloud-like lesions with indistinct margins. * **Why Option C is correct:** The nerve fiber layer contains the axons of ganglion cells. When ischemia occurs, orthograde and retrograde axonal transport is interrupted, causing "axonal debris" to accumulate, which manifests as a cotton wool spot. * **Why Option A is incorrect:** The **Outer Plexiform Layer (OPL)** is the site where **Hard Exudates** (lipid deposits from chronic vascular leakage) typically accumulate. This is a high-yield distinction for exams. * **Why Option B & D are incorrect:** The Inner Nuclear Layer and the Rods and Cones layer are involved in different pathologies (like deep hemorrhages or retinal dystrophies) but do not host the localized axonal swelling characteristic of soft exudates. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** On microscopic examination, cotton wool spots show characteristic **Cytoid bodies** (swollen ends of ruptured axons). * **Common Causes:** Diabetic Retinopathy (pre-proliferative stage), Hypertension, HIV retinopathy, and Retinal Vein Occlusions. * **Key Distinction:** * **Soft Exudates:** Nerve Fiber Layer (Ischemia/Infarction). * **Hard Exudates:** Outer Plexiform Layer (Lipid leakage/Henle's layer in the macula).

Q: Night blindness may be caused by all of the following except?

Lattice degeneration. **Explanation:** Night blindness (**Nyctalopia**) occurs due to the dysfunction of **rod photoreceptors**, which are responsible for vision in low-light conditions. **Why Lattice Degeneration is the correct answer:** Lattice degeneration is a peripheral retinal thinning characterized by an arborizing network of white lines. While it is a significant risk factor for **rhegmatogenous retinal detachment** due to vitreoretinal traction and holes, it typically does not affect rod function globally. It is usually asymptomatic and does not cause night blindness. **Analysis of Incorrect Options:** * **Vitamin A Deficiency:** Vitamin A is a precursor to **rhodopsin** (visual purple) in rods. Deficiency leads to impaired dark adaptation and is the most common cause of treatable night blindness worldwide. * **Retinitis Pigmentosa (RP):** A hereditary dystrophy primarily affecting the rods. Nyctalopia is the **earliest clinical symptom**, followed by ring scotoma and "bone-spicule" pigmentation. * **Syphilis:** Chronic syphilitic chorioretinitis can mimic the clinical appearance of Retinitis Pigmentosa (often called **Pseudo-RP**), leading to extensive rod damage and subsequent night blindness. **NEET-PG High-Yield Pearls:** * **Other causes of Nyctalopia:** Pathological myopia, Gyrate atrophy, Choroideremia, and Oguchi disease (stationary night blindness). * **Lattice Degeneration:** Most common in myopic eyes; found in roughly 8-10% of the general population. * **Vitamin A:** The first clinical sign of deficiency is impaired dark adaptation, while the first physical sign is **conjunctival xerosis**. * **RP Triad:** Arteriolar attenuation, bone-spicule pigmentation, and waxy disc pallor.

Q: All of the following are seen in Favre-Goldmann syndrome except?

Ectopia lentis. **Favre-Goldmann Syndrome** is a rare, autosomal recessive vitreoretinal dystrophy caused by mutations in the **NR2E3 gene**. It is characterized by a progressive degeneration of the retina and vitreous. ### Why Ectopia Lentis is the Correct Answer **Ectopia lentis** (displacement of the lens) is **not** a feature of Favre-Goldmann syndrome. It is typically associated with conditions involving systemic connective tissue disorders or zonular weakness, such as Marfan syndrome, Homocystinuria, or Weill-Marchesani syndrome. ### Explanation of Incorrect Options * **Retinoschisis (Option B):** This is a hallmark feature. Patients develop **foveal and peripheral retinoschisis** (splitting of the retinal layers), often leading to early vision loss. * **Nyctalopia (Option C):** Night blindness is a primary symptom. It occurs due to the progressive dysfunction of the photoreceptors, specifically the rods. * **Pigmentary changes (Option D):** The fundus often shows "bone-spicule" pigmentary changes, attenuated vessels, and optic disc pallor, mimicking the clinical appearance of **Retinitis Pigmentosa**. ### High-Yield Clinical Pearls for NEET-PG * **Genetics:** Autosomal Recessive; **NR2E3 gene** (Enhanced S-cone syndrome spectrum). * **Vitreous Findings:** Characterized by **optically empty vitreous** with fibrillar liquefaction (similar to Wagner’s or Stickler’s syndrome). * **Electroretinogram (ERG):** Shows a pathognomonic "Enhanced S-cone" response—increased sensitivity to blue light but severely reduced rod and long/medium-wavelength cone function. * **Differential Diagnosis:** Must be distinguished from X-linked Retinoschisis (which lacks the RP-like pigmentary changes) and Stickler Syndrome (which features high myopia and systemic skeletal issues).

Q: Which of the following is not a feature of Leber congenital amaurosis?

Autosomal Dominant inheritance. **Explanation:** **Leber Congenital Amaurosis (LCA)** is a severe group of inherited retinal dystrophies characterized by profound visual loss at birth or within the first year of life. **Why Option C is the correct answer:** LCA is primarily an **Autosomal Recessive (AR)** disorder. It is genetically heterogeneous, with mutations in genes such as *RPE65*, *GUCY2D*, and *CRB1*. Because the question asks for the feature that is **NOT** associated with LCA, Autosomal Dominant inheritance is the correct choice (though rare AD variants exist, the classic and exam-standard inheritance is AR). **Analysis of other options:** * **Option A (Pupillary reflexes are impaired):** Due to the severe, early-onset degeneration of photoreceptors, there is a lack of sensory input to the afferent limb of the light reflex, leading to sluggish or absent pupillary responses. * **Option B (Enophthalmos):** This is part of the **"Oculo-digital sign of Franceschetti."** Infants frequently poke or rub their eyes to stimulate the retina (phosphenes), which leads to the loss of orbital fat, resulting in enophthalmos and keratoconus. * **Option D (Most common retinal dystrophy in infants):** LCA is indeed the most common cause of inherited blindness in children, accounting for roughly 5% of all retinal dystrophies. **Clinical Pearls for NEET-PG:** * **Fundus Appearance:** Initially may appear normal (disproportionate to the severe vision loss), later developing "bone-spicule" pigmentation or a "salt and pepper" fundus. * **ERG Findings:** The Electroretinogram (ERG) is **non-recordable (extinguished)** even in early stages, which is a key diagnostic feature. * **Gene Therapy:** *Voretigene neparvovec* (Luxturna) is an FDA-approved gene therapy for LCA patients with the *RPE65* mutation, making it a high-yield topic for recent updates.

Q: Which of the following is NOT a presentation of retinoblastoma?

Cataract. **Explanation:** Retinoblastoma is the most common primary intraocular malignancy of childhood. Understanding its clinical presentation is crucial for NEET-PG, as early diagnosis is life-saving. **Why Cataract is the Correct Answer:** Cataract is **not** a typical presentation of retinoblastoma. In fact, the presence of a clear lens is a key clinical feature that helps differentiate retinoblastoma from other causes of "white eye" (pseudogliomas) like Persistent Fetal Vasculature (PFV) or congenital cataracts. While advanced tumors may rarely cause secondary lens changes due to inflammation or metabolic disturbances, it is not a primary or diagnostic presentation. **Analysis of Incorrect Options:** * **Leucocoria (A):** This is the **most common** presentation (60%). It refers to a white pupillary reflex caused by the tumor mass behind the lens. * **Squint/Strabismus (B):** This is the **second most common** presentation (20%). It occurs when the tumor involves the macula, leading to loss of central vision and subsequent sensory deviation of the eye. * **Glaucoma (D):** Secondary glaucoma is a known complication. It can occur due to neovascularization of the iris (NVI), anterior displacement of the iris-lens diaphragm by a large endophytic tumor, or tumor cells blocking the trabecular meshwork. **Clinical Pearls for NEET-PG:** * **Most common sign:** Leucocoria (Cat’s eye reflex). * **Inheritance:** Most cases are sporadic; however, heritable cases (40%) are due to a germline mutation in the **RB1 gene (Chromosome 13q14)** and are often bilateral. * **Pathognomonic Histology:** **Flexner-Wintersteiner rosettes** (highly specific). * **Calcification:** Intraocular calcification in a child under 3 years is retinoblastoma until proven otherwise (detected via B-scan USG or CT). * **Most common distant metastasis:** Bone marrow.

Q: Which of the following is not a cause of exudative retinal detachment?

Diabetic retinopathy. **Explanation:** The correct answer is **Diabetic Retinopathy** because it is primarily associated with **Tractional Retinal Detachment (TRD)**. In proliferative diabetic retinopathy, neovascularization leads to the formation of fibrovascular membranes. These membranes contract, pulling the neurosensory retina away from the underlying retinal pigment epithelium (RPE). While advanced cases may show a "combined" mechanism, the hallmark is traction, not exudation. **Analysis of Options:** * **Toxemia of Pregnancy (Eclampsia/Pre-eclampsia):** Severe systemic hypertension and vascular damage lead to choroidal ischemia and leakage of fluid into the subretinal space, causing exudative RD. * **Malignant Hypertension:** Similar to toxemia, extreme blood pressure elevations cause fibrinoid necrosis of choroidal arterioles, leading to RPE dysfunction and protein-rich fluid accumulation (exudative RD). * **Posterior Scleritis:** This inflammatory condition involves the sclera and choroid. The inflammation causes significant fluid leakage into the subretinal space, making it a classic cause of exudative RD. **High-Yield Clinical Pearls for NEET-PG:** 1. **Exudative RD (Solid/Serous):** Occurs due to fluid accumulation without a retinal break or traction. Key causes include **Vogt-Koyanagi-Harada (VKH) syndrome**, **Choroidal Melanoma**, and **Sympathetic Ophthalmitis**. 2. **Rhegmatogenous RD:** The most common type; caused by a **retinal break/hole** (e.g., in high myopes or post-trauma). 3. **Shifting Fluid Sign:** This is the pathognomonic clinical feature of Exudative RD, where subretinal fluid moves according to gravity when the patient changes position. 4. **Diabetic Retinopathy** is the most common cause of **Tractional RD** in the clinical setting.

Q: Bull's eye lesion in the macula is seen with which of the following medications?

Chloroquine. **Explanation:** **Chloroquine (and Hydroxychloroquine)** are the classic causes of **Bull’s eye maculopathy**. These drugs have a high affinity for melanin and accumulate in the **Retinal Pigment Epithelium (RPE)**. The toxicity manifests as a central area of RPE atrophy (pale) surrounded by a ring of spared RPE, which is further encircled by another ring of atrophy, giving the characteristic "Bull's eye" appearance on fundoscopy. This leads to progressive, irreversible visual field loss (scotomas). **Analysis of Incorrect Options:** * **Primaquine:** An antimalarial used for radical cure (liver stages); it is primarily associated with hematologic side effects like hemolysis in G6PD deficiency, not retinal toxicity. * **Quinine:** Known for causing **"Quinine Amblyopia."** Acute toxicity leads to sudden vision loss, pupillary abnormalities, and marked arteriolar narrowing (cherry red spot may be seen), but not a Bull's eye lesion. * **Sulfamethoxazole:** A sulfonamide that can cause hypersensitivity reactions (Stevens-Johnson Syndrome) or acute transient myopia/angle-closure glaucoma due to ciliary body edema, but it is not associated with macular pigmentary changes. **High-Yield Clinical Pearls for NEET-PG:** * **Other causes of Bull’s eye maculopathy:** Stargardt’s disease (most common genetic cause), Cone dystrophy, and Chronic Thioridazine toxicity. * **Screening:** The most sensitive tests for early detection are **Automated Visual Fields (10-2)** and **Spectral Domain OCT (SD-OCT)**, which shows the "Flying Saucer" sign (loss of outer retinal layers). * **Dosage:** Toxicity risk increases significantly when the daily dose of Hydroxychloroquine exceeds **5 mg/kg** of real body weight.

Q: Anomaloscope is used to detect:

Colour blindness. **Explanation:** The **Anomaloscope** (specifically the Nagel anomaloscope) is the **gold standard** for diagnosing and classifying congenital red-green color vision deficiencies. It operates on the principle of **metameric matching**. The subject is asked to match a "test field" (monochromatic yellow light) by mixing two "primary fields" (red and green light) in a split-screen view. By analyzing the proportions of red and green used to achieve a match, clinicians can differentiate between protanopia (red deficiency), deuteranopia (green deficiency), and their respective anomalous trichromacies. **Why other options are incorrect:** * **A. Squint:** Evaluated using tests like the Cover-Uncover test, Hirschberg corneal reflex test, and Synoptophore (which measures binocular single vision and angle of deviation). * **B. Retinopathy:** Diagnosed via Fundoscopy (Direct/Indirect Ophthalmoscopy), Optical Coherence Tomography (OCT), and Fluorescein Angiography (FFA) to visualize retinal vascular changes. * **C. Congenital Glaucoma:** Detected by measuring intraocular pressure (Tonometry), assessing corneal diameter (megalocornea), and observing optic disc cupping. **High-Yield Clinical Pearls for NEET-PG:** * **Ishihara Charts:** The most common screening tool for color blindness; however, it cannot detect blue-yellow (tritan) defects. * **Hardy-Rand-Rittler (HRR) Plates:** Can detect all three types of defects (Protan, Deutan, and Tritan). * **Farnsworth-Munsell 100 Hue Test:** Used for detailed assessment of the severity of color vision loss. * **Inheritance:** Most congenital color blindness is **X-linked recessive**, making it significantly more common in males.

Q: What happens to the number of pericytes in diabetic retinopathy?

Decreases. **Explanation:** In Diabetic Retinopathy (DR), the **loss of pericytes** is the earliest histopathological hallmark of the disease. Pericytes are contractile cells wrapped around retinal capillaries that provide structural support and regulate blood flow. Chronic hyperglycemia leads to the accumulation of sorbitol (via the polyol pathway) and Advanced Glycation End-products (AGEs), which are toxic to pericytes. As pericytes undergo apoptosis, the capillary wall weakens, leading to the formation of **microaneurysms** (the first clinical sign of DR). This loss also disrupts the blood-retinal barrier, resulting in vascular leakage and exudation. **Analysis of Options:** * **Option A (Increases):** Incorrect. Hyperglycemia is cytotoxic to pericytes; they never increase in number during the progression of DR. * **Option B (Decreases):** **Correct.** Selective pericyte loss is the "signature" lesion of early diabetic microangiopathy. * **Option C (No change):** Incorrect. Significant structural changes occur at the cellular level long before clinical symptoms appear. * **Option D (Decreases followed by increases):** Incorrect. Once pericytes are lost, they do not regenerate; instead, the basement membrane thickens and acellular capillaries form. **High-Yield Clinical Pearls for NEET-PG:** 1. **Pericyte to Endothelial Cell Ratio:** In a normal retina, the ratio is **1:1**. In diabetic retinopathy, this ratio significantly decreases. 2. **Earliest Clinical Sign:** Microaneurysms (seen as tiny red dots on fundoscopy). 3. **Earliest Pathological Sign:** Loss of pericytes and basement membrane thickening. 4. **Aldose Reductase:** The enzyme responsible for converting glucose to sorbitol, leading to pericyte death.

Q: What is a common cause of floaters in Diabetes Mellitus?

Vitreous hemorrhage. **Explanation:** In the context of Diabetes Mellitus, the sudden appearance of floaters is most commonly attributed to **Vitreous Hemorrhage**. This occurs during the stage of **Proliferative Diabetic Retinopathy (PDR)**. Chronic hypoxia triggers the release of Vascular Endothelial Growth Factor (VEGF), leading to **neovascularization** (NVD/NVE). These new vessels are fragile and lack a proper basement membrane; they easily rupture due to vitreoretinal traction, leaking blood into the vitreous cavity. Patients typically describe "cobwebs," "dark streaks," or "spots" (floaters), which may progress to sudden painless loss of vision if the bleed is extensive. **Analysis of Incorrect Options:** * **Vitreous Detachment (PVD):** While a common cause of floaters in the elderly and myopes, it is not the specific pathological hallmark of diabetic eye disease compared to hemorrhage. * **Maculopathy:** Diabetic Macular Edema (DME) is the most common cause of *gradual* vision loss in diabetics. It presents with blurring or metamorphopsia (distortion), not floaters. * **Infarction:** Retinal infarction (e.g., Cotton Wool Spots) represents localized ischemia of the nerve fiber layer. It is usually asymptomatic unless it involves the fovea and does not cause floaters. **NEET-PG High-Yield Pearls:** * **Classification:** PDR is defined by the presence of neovascularization. * **Management:** The gold standard for PDR is **Pan-Retinal Photocoagulation (PRP)**. For non-clearing vitreous hemorrhage, **Pars Plana Vitrectomy (PPV)** is indicated. * **Investigation:** If the fundus is obscured by blood, an **Ocular B-Scan** must be performed to rule out tractional retinal detachment.

Question 1

Soft exudates (cotton wool spots) are typically found in which layer of the retina?

Accepted Answer

Nerve fiber layer

Answer

Outer plexiform layer

Answer

Inner nuclear layer

Answer

Rods and cones cell layer

Question 2

Night blindness may be caused by all of the following except?

Accepted Answer

Lattice degeneration

Answer

Vitamin A deficiency

Answer

Retinitis pigmentosa

Answer

Syphilis

Question 3

All of the following are seen in Favre-Goldmann syndrome except?

Accepted Answer

Ectopia lentis

Answer

Retinoschisis

Answer

Nyctalopia

Answer

Pigmentary changes similar to retinitis pigmentosa

Question 4

Which of the following is not a feature of Leber congenital amaurosis?

Accepted Answer

Autosomal Dominant inheritance

Answer

Pupillary reflexes are impaired

Answer

Enophthalmos

Answer

Most common retinal dystrophy in infants

Question 5

Which of the following is NOT a presentation of retinoblastoma?

Accepted Answer

Cataract

Answer

Leucocoria

Answer

Squint

Answer

Glaucoma

Question 6

Which of the following is not a cause of exudative retinal detachment?

Accepted Answer

Diabetic retinopathy

Answer

Toxemia of pregnancy

Answer

Malignant hypertension

Answer

Posterior scleritis

Question 7

Bull's eye lesion in the macula is seen with which of the following medications?

Accepted Answer

Chloroquine

Answer

Primaquine

Answer

Quinine

Answer

Sulfamethoxazole

Question 8

Anomaloscope is used to detect:

Accepted Answer

Colour blindness

Answer

Squint

Answer

Retinopathy

Answer

Congenital glaucoma

Question 9

What happens to the number of pericytes in diabetic retinopathy?

Accepted Answer

Decreases

Answer

Increases

Answer

No change

Answer

Decreases followed by increases

Question 10

What is a common cause of floaters in Diabetes Mellitus?

Accepted Answer

Vitreous hemorrhage

Answer

Vitreous detachment

Answer

Maculopathy

Answer

Infarction

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

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