Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 81: Regarding color blindness, which of the following statements are true?

A. Mainly congenital (Correct Answer)
B. Can be tested with the Farnsworth 100 hue test
C. Ishihara chart tests red/green color blindness
D. Jerlin-Merlin cotton wool tests it

Explanation: **Explanation:** **Color blindness** (Color Vision Deficiency) is a common high-yield topic in NEET-PG. 1. **Why Option A is Correct:** Most cases of color blindness are **congenital**, resulting from X-linked recessive mutations affecting the photopigments in retinal cones. This explains why it is significantly more common in males (8%) than females (0.5%). While acquired causes exist (e.g., optic neuritis, toxic amblyopia), the vast majority of clinical cases are hereditary. 2. **Analysis of Other Options:** * **Option B:** While the **Farnsworth-Munsell 100 Hue Test** is indeed used to assess color vision, the question asks for the "most true" or primary characteristic. In many MCQ formats, if a general characteristic (congenital nature) is pitted against a specific test, the etiology is prioritized. However, note that B and C are technically accurate statements; in a "Multiple True" format, they would be correct. * **Option C:** The **Ishihara Chart** is the most common screening tool specifically designed to detect **Red-Green** color blindness. It cannot detect Blue-Yellow defects (Tritanopia). * **Option D:** This is a distractor. There is no "Jerlin-Merlin cotton wool test" for color vision. Cotton wool spots are clinical findings in diabetic or hypertensive retinopathy, not a color vision test. **High-Yield Clinical Pearls for NEET-PG:** * **Kollner’s Rule:** Outer retinal diseases (e.g., ARMD) usually cause Blue-Yellow defects, while optic nerve diseases (e.g., Glaucoma, Optic Neuritis) cause Red-Green defects. *Exception: Glaucoma and Papilledema often cause Blue-Yellow defects initially.* * **Nagel’s Anomaloscope:** The gold standard for definitive diagnosis and qualitative assessment of color blindness. * **Protanopia:** Red deficiency; **Deuteranopia:** Green deficiency (most common); **Tritanopia:** Blue deficiency.

Question 82: A 40-year-old male with diabetes presents with vitreous hemorrhage. What is the most likely cause?

A. Posterior retinal detachment
B. Neovascularization at the optic disc (Correct Answer)
C. Central retinal vein occlusion
D. Trauma to the central retinal artery

Explanation: ### Explanation **Correct Answer: B. Neovascularization at the optic disc (NVD)** In a diabetic patient, the most common cause of spontaneous vitreous hemorrhage is **Proliferative Diabetic Retinopathy (PDR)**. Chronic retinal ischemia leads to the release of Vascular Endothelial Growth Factor (VEGF), which stimulates the formation of fragile, abnormal new vessels (neovascularization) at the optic disc (NVD) or elsewhere in the retina (NVE). These vessels lack a proper basement membrane and are prone to bleeding into the vitreous cavity, especially following vitreous contraction. **Analysis of Incorrect Options:** * **A. Posterior retinal detachment:** While PDR can lead to *tractional* retinal detachment, the detachment itself is usually a consequence of the fibrovascular proliferation rather than the primary cause of the hemorrhage. * **C. Central retinal vein occlusion (CRVO):** Although CRVO can cause vitreous hemorrhage via neovascularization (90-day glaucoma), it is less common than PDR in a 40-year-old diabetic male. * **D. Trauma to the central retinal artery:** The central retinal artery is an internal structure; trauma typically results in occlusion (ischemia) rather than vitreous hemorrhage. **NEET-PG High-Yield Pearls:** * **Most common cause of Vitreous Hemorrhage:** Trauma (overall); PDR (spontaneous/medical). * **Clinical Sign:** "Fresh" vitreous hemorrhage presents as a sudden, painless loss of vision with a "black rain" or "cobweb" sensation (floaters). * **Investigation of Choice:** If the fundus is obscured by blood, perform a **B-Scan Ultrasound** to rule out retinal detachment. * **Management:** Conservative (head elevation) or Pars Plana Vitrectomy (PPV) if the hemorrhage fails to resolve or if tractional detachment occurs.

Question 83: Salt and pepper fundus occurs in which of the following conditions?

A. Toxoplasma
B. Toxocara
C. Rubella (Correct Answer)
D. Ehlers Danlos syndrome

Explanation: **Explanation:** The term **"Salt and Pepper Fundus"** refers to a characteristic clinical appearance of the retina where there are diffuse, mottled areas of pigmentary hypertrophy (black "pepper") and atrophy (white "salt"). 1. **Congenital Rubella (Correct Answer):** This is the most common ocular manifestation of the Rubella virus. It occurs due to damage to the **Retinal Pigment Epithelium (RPE)**. Despite the dramatic appearance of the fundus, the visual acuity is usually preserved, and the condition is non-progressive. It is part of the "Gregg Triad" (Cataract, Heart defects, and Deafness). 2. **Toxoplasma (Incorrect):** Typically presents as a "headlight in the fog" appearance due to active focal necrotizing retinochoroiditis with overlying vitritis. Healed lesions appear as punched-out chorioretinal scars with pigmented borders. 3. **Toxocara (Incorrect):** Usually presents as a unilateral posterior pole granuloma or peripheral tractional bands leading to leukocoria (white pupillary reflex). 4. **Ehlers-Danlos Syndrome (Incorrect):** This connective tissue disorder is classically associated with **Angioid Streaks** (breaks in Bruch’s membrane) and high myopia, not salt and pepper retinopathy. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis of Salt and Pepper Fundus:** * Congenital Rubella (Most common) * Congenital Syphilis * Leber’s Congenital Amaurosis (LCA) * Cystinosis * Phenothiazine toxicity (Thioridazine) * **Key Distinction:** Unlike Retinitis Pigmentosa, Salt and Pepper fundus in Rubella does **not** typically show "bony spicule" pigmentation or significant arteriolar narrowing.

Question 84: Which of the following is NOT a difference between Fluorescein Angiography (FA) and Indocyanine Green (ICG) angiography?

A. Dyes used
B. Choroidal capillaries are better visualized in ICG
C. FA is more sensitive for occult CNVM (Correct Answer)
D. The wavelength used for viewing is different

Explanation: **Explanation:** The core concept distinguishing these two imaging modalities lies in the **physical properties of the dyes** and their ability to penetrate the Retinal Pigment Epithelium (RPE). **Why Option C is the correct answer (The "NOT" difference):** In reality, **ICG is more sensitive for Occult Choroidal Neovascular Membranes (CNVM)**, while FA is superior for Classic CNVM. Occult CNVM is located beneath the RPE; because ICG uses near-infrared light, it penetrates the RPE and blood better than the visible light used in FA. Therefore, the statement that "FA is more sensitive for occult CNVM" is clinically incorrect, making it the right choice for this "NOT" question. **Analysis of Incorrect Options:** * **A. Dyes used:** This is a valid difference. FA uses **Sodium Fluorescein**, while ICG uses **Indocyanine Green**. * **B. Choroidal capillaries:** This is a valid difference. ICG is 98% protein-bound (to albumin), keeping it within the fenestrated choriocapillaris, whereas Fluorescein leaks out rapidly. Combined with infrared penetration, ICG provides far superior visualization of the choroidal circulation. * **D. Wavelength:** This is a valid difference. FA uses visible light (Excitation: 490nm; Emission: 530nm), whereas ICG uses near-infrared light (Excitation: 805nm; Emission: 835nm). **High-Yield Clinical Pearls for NEET-PG:** * **FA** is the gold standard for **Retinal vascular diseases** (e.g., Diabetic Retinopathy, BRVO). * **ICG** is the gold standard for **Choroidal diseases** (e.g., PCV - Polypoidal Choroidal Vasculopathy, and Occult CNVM). * **Contraindication:** Avoid ICG in patients with **Iodine allergy** (as the dye contains iodine) or liver disease. * **Side Effects:** Nausea is common in FA; anaphylaxis is rare but more common in FA than ICG.

Question 85: The retinal capillaries are distinguished by having all features except:

A. Widening of the capillary calibre in the periphery
B. Capillary-free zone around the veins (Correct Answer)
C. Superficial network
D. Deep denser network

Explanation: The retinal microvasculature has a unique anatomical arrangement essential for maintaining the blood-retinal barrier and metabolic supply. **Explanation of the Correct Option:** **Option B (Capillary-free zone around the veins)** is the correct answer because it is a false statement. In the retina, a distinct **peri-arterial capillary-free zone** exists (approximately 50–120 μm wide), where capillaries are absent immediately adjacent to the arterioles. This is likely due to the high oxygen tension surrounding the arterioles. There is **no such capillary-free zone around the veins**; capillaries frequently drain directly into or lie in close proximity to the venules. **Analysis of Other Options:** * **Option A (Widening of calibre):** Retinal capillaries are narrowest at the posterior pole (approx. 7 μm) and undergo a **widening of calibre** as they move toward the periphery (up to 50–100 μm), forming a simpler, wider-meshed network near the ora serrata. * **Option C & D (Superficial and Deep networks):** The retinal vasculature is organized into two primary layers: * **Superficial network:** Located in the nerve fiber layer (NFL) or ganglion cell layer. * **Deep network:** A denser, more complex network located in the inner nuclear layer. **High-Yield Clinical Pearls for NEET-PG:** * **Foveal Avascular Zone (FAZ):** A 0.5 mm diameter area at the center of the fovea that is completely devoid of capillaries. Enlargement of the FAZ on Fluorescein Angiography (FFA) is a key sign of **macular ischemia** (e.g., in Diabetic Retinopathy). * **Blood-Retinal Barrier (BRB):** The inner BRB is formed by the **non-fenestrated endothelial cells** of the retinal capillaries (tight junctions/Zonula occludens). * **Pericyte Loss:** The earliest histopathological change in Diabetic Retinopathy is the selective loss of pericytes, leading to microaneurysm formation.

Question 86: Jet-black spots in the retina are seen in which condition?

A. Retinoblastoma
B. Diabetic retinopathy
C. Retinitis pigmentosa (Correct Answer)
D. Hypertensive retinopathy

Explanation: **Explanation:** **Retinitis Pigmentosa (RP)** is a hereditary dystrophy primarily affecting the rod photoreceptors. The characteristic "jet-black spots" are known as **bone-spicule pigmentary changes**. These occur because the degeneration of photoreceptors leads to the migration of retinal pigment epithelium (RPE) cells into the inner retinal layers, where they aggregate around retinal capillaries in a branching pattern resembling bone corpuscles. This typically begins in the mid-periphery and is associated with the clinical triad of night blindness (nyctalopia), tubular vision, and a waxy pallor of the optic disc. **Why other options are incorrect:** * **Retinoblastoma:** Presents typically as a "leukocoria" (white pupillary reflex). While calcification may be seen on imaging, jet-black pigmentary migration is not a feature. * **Diabetic Retinopathy:** Characterized by microaneurysms, dot-and-blot hemorrhages, hard exudates, and neovascularization, but not bone-spicule pigmentation. * **Hypertensive Retinopathy:** Features include arteriolar narrowing, AV nipping, flame-shaped hemorrhages, and Cotton Wool spots. In severe cases (Grade IV), Macular Star and papilledema are seen. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad of RP:** 1. Bone-spicule pigmentation, 2. Arteriolar attenuation (narrowing), 3. Waxy pallor of the optic disc. * **Electroretinogram (ERG):** The most sensitive test for early diagnosis; it shows a reduced or "extinguished" a- and b-wave. * **Visual Field:** Characteristically shows a **ring scotoma**, which eventually progresses to tunnel vision. * **Associations:** Often associated with Usher syndrome (deafness) and Bassen-Kornzweig syndrome (acanthocytosis).

Question 87: A young male presents with a central scotoma in the left eye. His right eye vision is 6/6. Fundoscopic examination reveals focal foveal detachment in the left eye. What would be the next step in management?

A. Examine for retrolental cells
B. Inquire about the use of steroids (Correct Answer)
C. Ask for a history of trauma in the other eye
D. Perform examination under a slit lamp

Explanation: **Explanation:** The clinical presentation of a young male with a sudden central scotoma and focal foveal detachment is classic for **Central Serous Chorioretinopathy (CSCR)**. CSCR is characterized by an idiopathic serous detachment of the neurosensory retina at the macula due to leakage from the choriocapillaris through a defect in the Retinal Pigment Epithelium (RPE). **Why Option B is correct:** The most significant and well-documented risk factor for the development or exacerbation of CSCR is the use of **exogenous steroids** (systemic, inhaled, topical, or even nasal). Steroids increase capillary fragility and alter the permeability of the choriocapillaris. Therefore, the immediate next step in management is to identify and discontinue any steroid use, as most cases of CSCR resolve spontaneously once the trigger is removed. **Why other options are incorrect:** * **Option A:** Retrolental cells (cells in the anterior vitreous) are markers of posterior uveitis. While uveitis can cause macular edema, the focal foveal detachment in a young male is more indicative of CSCR than inflammation. * **Option C:** History of trauma in the *other* eye is relevant for Sympathetic Ophthalmitis, which presents with bilateral granulomatous panuveitis, not isolated focal detachment. * **Option D:** While a slit-lamp exam is necessary for diagnosis, the question asks for the "next step" in the context of identifying the etiology. Inquiring about steroids is a high-yield clinical priority. **High-Yield Pearls for NEET-PG:** * **Demographics:** Typically affects young to middle-aged males with "Type A" personalities. * **FFA Finding:** Classic "Ink-blot" or "Smoke-stack" appearance. * **OCT Finding:** Neurosensory detachment with or without a Pedunculated Pigment Epithelial Detachment (PED). * **Management:** Observation (most resolve in 3–4 months). If persistent, consider Photodynamic Therapy (PDT) or Micropulse Laser.

Question 88: Which of the following is NOT a risk factor for retinal detachment?

A. Diabetic retinopathy
B. Myopia
C. Hypermetropia (Correct Answer)
D. Central Retinal Vein Occlusion (CRVO)

Explanation: **Explanation:** The correct answer is **Hypermetropia**. Retinal detachment (RD) occurs when the neurosensory retina separates from the underlying retinal pigment epithelium (RPE). Understanding the risk factors depends on the type of RD (Rhegmatogenous, Tractional, or Exudative). **Why Hypermetropia is NOT a risk factor:** Hypermetropia (farsightedness) is associated with a **shorter axial length** of the eyeball. This results in a thicker sclera and less stretching of the peripheral retina. In contrast, **Myopia** (Option B) is a major risk factor because the elongated eyeball leads to thinning of the retina and peripheral degenerations (like Lattice degeneration), which predispose to retinal tears and Rhegmatogenous RD. **Analysis of other options:** * **Diabetic Retinalpathy (Option A):** This is a classic cause of **Tractional RD**. Proliferative changes lead to the formation of fibrovascular membranes that contract and pull the retina away from its base. * **Central Retinal Vein Occlusion (Option D):** CRVO can lead to **Exudative (Serous) RD** due to increased vascular permeability and the breakdown of the blood-retinal barrier, or Tractional RD if neovascularization develops. **High-Yield Clinical Pearls for NEET-PG:** * **Most common type of RD:** Rhegmatogenous RD (associated with Myopia, trauma, and aphakia). * **Most common peripheral degeneration leading to RD:** Lattice degeneration. * **Classic Symptoms:** Sudden onset of flashes (photopsia), floaters, and a "curtain-like" loss of vision. * **Shafer’s Sign:** "Tobacco dust" (pigment cells) in the anterior vitreous is pathognomonic for a retinal tear. * **Management:** Rhegmatogenous RD requires surgery (Scleral buckling or Pars Plana Vitrectomy); Tractional RD requires Vitrectomy; Exudative RD is managed by treating the underlying medical cause.

Question 89: Which of the following is not a prerequisite for performing pneumatic retinopexy?

A. Fresh retinal detachment
B. Inferior retinal detachment (Correct Answer)
C. No air travel
D. Patient should be able to maintain position

Explanation: **Explanation:** Pneumatic retinopexy (PR) is a minimally invasive procedure used to treat rhegmatogenous retinal detachment (RRD). It involves injecting an expansile gas bubble (like $SF_6$ or $C_3F_8$) into the vitreous cavity to tamponade the retinal break. **Why Option B is the Correct Answer:** The fundamental principle of PR is **buoyancy**. The gas bubble rises to the highest point in the eye. Therefore, PR is indicated for breaks located in the **superior 8 clock hours** (between 8 o’clock and 4 o’clock). It is **not suitable for inferior retinal breaks** because the gas bubble cannot effectively tamponade a break at the bottom of the eye unless the patient is placed in a physically impossible head-down position. **Analysis of Incorrect Options:** * **A. Fresh retinal detachment:** PR is most successful in acute RRDs where the subretinal fluid is mobile and there is no significant proliferative vitreoretinopathy (PVR Grade C or D). * **C. No air travel:** This is a critical safety prerequisite. Atmospheric pressure changes during flight cause the intraocular gas bubble to expand rapidly, leading to a dangerous spike in intraocular pressure (IOP) and central retinal artery occlusion. * **D. Patient positioning:** Success depends entirely on the patient’s ability to maintain a specific head posture (e.g., "nose-to-shoulder") for several days to ensure the bubble stays against the break. **Clinical Pearls for NEET-PG:** * **Ideal Candidate:** Single break or a group of breaks within 1 clock hour in the superior retina. * **Common Gases:** Sulfur hexafluoride ($SF_6$) and Perfluoropropane ($C_3F_8$). * **The "Steamroller" Maneuver:** A technique used during PR to push subretinal fluid away from the macula. * **Contraindications:** Glaucoma (uncontrolled), cloudy media, and inferior breaks.

Question 90: Annular ring scotoma is seen in which of the following conditions?

A. Retinitis pigmentosa (Correct Answer)
B. Night blindness
C. Severe myopia
D. Angle closure glaucoma

Explanation: **Explanation:** **Retinitis Pigmentosa (RP)** is a hereditary dystrophy primarily affecting the rod photoreceptors. The characteristic visual field defect in RP is an **annular (ring) scotoma**. This occurs because the degeneration typically begins in the mid-peripheral retina (where rod density is highest). As the disease progresses, these mid-peripheral field defects coalesce to form a circular ring of vision loss, eventually leaving only a small central area of "tunnel vision" before total blindness occurs. **Analysis of Incorrect Options:** * **Night Blindness (Nyctalopia):** This is a *symptom*, not a specific disease entity. While it is the earliest symptom of RP, it describes the inability to see in low light rather than a specific pattern of visual field loss. * **Severe Myopia:** High myopia is typically associated with peripheral field contraction, temporal crescents, or central scotomas (if Forster-Fuchs spots develop), but not a classic annular scotoma. * **Angle Closure Glaucoma:** Acute episodes present with sudden vision loss and halos. Chronic glaucoma (Open Angle) typically presents with arcuate (Bjerrum) scotomas or paracentral scotomas, which may eventually lead to tunnel vision, but the classic "annular" description is specific to RP. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad of RP:** 1. Bony spicule pigmentation (perivascular), 2. Arteriolar attenuation (narrowing), 3. Waxy pallor of the optic disc. * **ERG Findings:** The Electroretinogram (ERG) is the most sensitive test for early diagnosis and shows a **subnormal or extinguished** (flat) response even before fundus changes appear. * **Inheritance:** Most common is Autosomal Recessive; most severe is X-linked Recessive. * **Differential for Ring Scotoma:** Apart from RP, it can be seen in Vitamin A deficiency, Chloroquine toxicity, and Glaucoma (double arcuate scotoma).

Practice by Chapter

Retinal Anatomy and Physiology

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Age-Related Macular Degeneration

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Diabetic Retinopathy

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Retinal Vascular Diseases

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Retinal Detachment

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Hereditary Retinal Dystrophies

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Inflammatory Retinal Diseases

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Retinal Tumors

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Retinopathy of Prematurity

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Retinal Imaging Techniques

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Intravitreal Pharmacotherapy

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Vitreoretinal Surgery

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