Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 151: All of the following may be associated with night-blindness except?

A. Pathological myopia
B. Retinitis pigmentosa
C. Retinitis punctata albescens
D. Retinitis proliferans (Correct Answer)

Explanation: **Explanation:** Night blindness (Nyctalopia) occurs due to the dysfunction of **rod photoreceptors** or structural damage to the peripheral retina and choroid. **Why Retinitis Proliferans is the correct answer:** Retinitis proliferans is a late-stage complication of proliferative vitreoretinopathy or diabetic retinopathy, characterized by the formation of fibrovascular membranes on the retinal surface. It primarily leads to **tractional retinal detachment** and severe vision loss, but it is not a primary cause of night blindness. It affects the retinal architecture globally rather than specifically targeting the rod-mediated scotopic system. **Analysis of other options:** * **Retinitis Pigmentosa:** The classic cause of night blindness. It is a pigmentary retinal dystrophy that primarily destroys rods in the mid-periphery, leading to "ring scotoma" and tunnel vision. * **Retinitis Punctata Albescens:** A variant of RP (stationary or progressive) characterized by multiple white dots scattered across the fundus. It presents with early-onset night blindness. * **Pathological Myopia:** High myopia leads to chorioretinal degeneration and thinning of the peripheral retina. This structural damage impairs rod function, frequently causing night blindness. **High-Yield Clinical Pearls for NEET-PG:** * **Vitamin A Deficiency:** The most common cause of reversible night blindness worldwide. * **Oguchi’s Disease:** A rare autosomal recessive condition causing congenital stationary night blindness, characterized by the **Mizuo-Nakamura phenomenon** (golden-yellow fundus reflex that disappears after dark adaptation). * **Gyrate Atrophy:** An inborn error of ornithine metabolism causing "garland-shaped" chorioretinal atrophy and night blindness. * **Fundus Albipunctatus:** Another "white dot syndrome" causing stationary night blindness, often confused with Retinitis punctata albescens.

Question 152: Which of the following agents is not used in the treatment of Diabetic Macular Edema/Retinopathy?

A. Ruboxistaurin
B. Pyridazinones
C. Benfotiamine
D. Tamoxifen (Correct Answer)

Explanation: **Explanation:** The correct answer is **Tamoxifen**. In fact, Tamoxifen is not a treatment for Diabetic Retinopathy (DR); rather, it is a known cause of **toxic retinopathy**. Tamoxifen, a selective estrogen receptor modulator (SERM) used in breast cancer, can cause "Tamoxifen Retinopathy," characterized by bilateral, fine, yellow, crystalline deposits in the macula, which may lead to macular edema and decreased vision. **Analysis of Options:** * **Ruboxistaurin (Option A):** This is a specific inhibitor of **Protein Kinase C (PKC-beta)**. PKC activation is a key pathway in the pathogenesis of diabetic microvascular complications. Ruboxistaurin has been studied to reduce the progression of DR and visual loss. * **Pyridazinones (Option B):** These act as **Aldose Reductase Inhibitors (ARIs)**. The polyol pathway (glucose to sorbitol via aldose reductase) is a major contributor to osmotic stress in diabetic retinal cells. * **Benfotiamine (Option C):** A lipid-soluble derivative of Vitamin B1 (Thiamine). It inhibits the formation of **Advanced Glycation End-products (AGEs)** and reduces oxidative stress, thereby protecting the retinal capillaries from hyperglycemic damage. **High-Yield Clinical Pearls for NEET-PG:** 1. **Gold Standard Treatment:** Intravitreal Anti-VEGF (Ranibizumab, Aflibercept) is currently the first-line treatment for clinically significant macular edema (CSME). 2. **Crystalline Retinopathy D/D:** Tamoxifen, Canthaxanthin, Talc (in IV drug users), and Bietti’s Crystalline Dystrophy. 3. **Pathogenesis of DR:** Remember the mnemonic **"PAGE"**—**P**KC activation, **A**GE accumulation, **G**lucose (Polyol) pathway, and **E**xcessive oxidative stress. All options A, B, and C target these specific pathways.

Question 153: A patient presented with peripheral field loss and fundus examination shows waxy exudates and pale disc with pigmentation around retinal vessels. What is the diagnosis?

A. Behcet's syndrome
B. Chorioretinitis
C. Open-angle glaucoma
D. Retinitis pigmentosa (Correct Answer)

Explanation: **Explanation:** The clinical presentation described is the classic **triad of Retinitis Pigmentosa (RP)**, a hereditary dystrophy primarily affecting the rod photoreceptors. 1. **Why Retinitis Pigmentosa is correct:** The diagnosis is based on three hallmark funduscopic findings: * **Bony Spicule Pigmentation:** Melanin pigment migrates from the RPE and deposits in a perivascular pattern, typically starting in the mid-periphery. * **Arteriolar Attenuation:** Retinal vessels become thin and thread-like. * **Waxy Pallor of the Disc:** Resulting from consecutive optic atrophy. The **peripheral field loss** (ring scotoma progressing to tubular vision) occurs because rods, which are concentrated in the periphery, are affected first. 2. **Why other options are incorrect:** * **Behcet’s Syndrome:** Characterized by recurrent uveitis, hypopyon, and occlusive vasculitis (peri-phlebitis), not bone-spicule pigmentation. * **Chorioretinitis:** Presents with focal white/yellow inflammatory patches and vitreous haze (vitritis). While it can leave scars, it does not follow the symmetrical, generalized perivascular pattern of RP. * **Open-angle Glaucoma:** Causes peripheral field loss and optic disc changes, but the disc shows **pathological cupping**, not waxy pallor, and there is no retinal pigmentation. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Symptom:** Nyctalopia (Night blindness). * **Earliest Sign:** Increase in dark adaptation threshold. * **Gold Standard Investigation:** **Electroretinogram (ERG)**, which shows a "subnormal" or "extinguished" (flat) wave even before fundus changes appear. * **Associated Conditions:** Usher’s syndrome (deafness), Laurence-Moon-Biedl syndrome (obesity, polydactyly, hypogonadism). * **Common Complication:** Posterior Subcapsular Cataract (PSC) and Cystoid Macular Edema (CME).

Question 154: Hemorrhage at the macular spot in high myopia is called:

A. Lacquer's lines
B. Foster-Fuchs fleck (Correct Answer)
C. Dalen-Fuchs nodules
D. Berlin's edema

Explanation: **Explanation:** **Foster-Fuchs Fleck** (or Fuchs’ spot) is a circular, pigmented lesion at the macula caused by subretinal neovascularization (SRNV) in patients with **pathological (high) myopia**. The process begins with a rupture in the Bruch’s membrane, leading to a small subretinal hemorrhage. As the hemorrhage organizes, it results in a raised, pigmented scar. This is a classic high-yield finding for myopia-related vision loss. **Analysis of Incorrect Options:** * **A. Lacquer’s lines:** These are fine, irregular, yellowish-white linear streaks representing healed mechanical cracks in the Bruch’s membrane. While they are a hallmark of high myopia and often precede a Fuchs’ spot, they are not hemorrhages themselves. * **C. Dalen-Fuchs nodules:** These are small, yellow-white inflammatory nodules located between the RPE and Bruch’s membrane. They are characteristic of **Sympathetic Ophthalmitis** and Vogt-Koyanagi-Harada (VKH) syndrome, not myopia. * **D. Berlin’s edema:** Also known as *Commotio Retinae*, this is a milky-white opacification of the retina caused by blunt trauma, typically involving the macula. **High-Yield Clinical Pearls for NEET-PG:** * **Pathological Myopia** is defined as refractive error > -6.00D or axial length > 26.5 mm. * **Staphyloma:** Posterior bulging of the weakened sclera is the most characteristic sign of pathological myopia. * **Other Myopic findings:** Temporal crescent (at the optic disc), "Paving stone" degeneration, and increased risk of Rhegmatogenous Retinal Detachment.

Question 155: Major retinal vessels are present in which layer of the retina?

A. Between the vitreous and internal limiting membrane
B. The nerve fibre layer (Correct Answer)
C. The inner plexiform layer
D. The inner nuclear layer

Explanation: **Explanation:** The retina receives a dual blood supply: the outer layers (photoreceptors to the outer plexiform layer) are nourished by the choriocapillaris via diffusion, while the inner layers are supplied by the **Central Retinal Artery (CRA)**. **Why the Nerve Fibre Layer (NFL) is correct:** Upon entering the eye through the optic disc, the Central Retinal Artery divides into superior and inferior branches. These **major retinal vessels** (arterioles and venules) are anatomically located within the **Nerve Fibre Layer (NFL)**, just deep to the Internal Limiting Membrane (ILM). From this superficial location, they give rise to two capillary networks: the superficial capillary plexus (in the NFL/Ganglion cell layer) and the deep capillary plexus (in the Inner Nuclear Layer). **Analysis of Incorrect Options:** * **Option A:** The space between the vitreous and ILM is a potential space. Vessels located here are considered "pre-retinal" (e.g., neovascularization in proliferative diabetic retinopathy) and are pathological. * **Option C:** The Inner Plexiform Layer contains synaptic connections and smaller capillary branches, but not the major trunk vessels. * **Option D:** The Inner Nuclear Layer contains the deep capillary plexus, which consists of fine capillaries, not the major retinal vessels. **Clinical Pearls for NEET-PG:** * **Blood-Retinal Barrier (BRB):** The inner BRB is formed by the non-fenestrated endothelial cells of these retinal capillaries. * **Cherry Red Spot:** In CRAO, the NFL becomes edematous and opaque, but the foveola remains red because it lacks the NFL and is supplied by the underlying choroid. * **Flame-shaped Hemorrhages:** These occur in the NFL (e.g., in HTN retinopathy) because the blood tracks along the horizontally oriented nerve fibers.

Question 156: Indirect ophthalmoscopy is used for examination of which part of the eye?

A. Central retina
B. Periphery of retina (Correct Answer)
C. Sclera
D. Angle of anterior chamber

Explanation: **Explanation:** **Indirect Ophthalmoscopy (IDOP)** is the gold standard for examining the **periphery of the retina** (Option B). Unlike direct ophthalmoscopy, which provides high magnification but a very narrow field of view (approx. 10°), IDOP offers a wide field of view (approx. 30°–60°). When combined with **scleral depression**, it allows the clinician to visualize the retina as far as the **ora serrata**, making it indispensable for detecting peripheral lesions like retinal tears, holes, or lattice degeneration. **Analysis of Incorrect Options:** * **A. Central Retina:** While the central retina (macula and disc) can be seen with IDOP, it is better evaluated using **Direct Ophthalmoscopy** or **Slit-lamp Biomicroscopy (90D/78D lenses)** due to the higher magnification required to see fine details. * **C. Sclera:** The sclera is the outer white coat of the eye, usually examined via simple inspection or slit-lamp examination, not ophthalmoscopy. * **D. Angle of Anterior Chamber:** This is visualized using **Gonioscopy** (e.g., Goldmann 3-mirror lens), as the angle is hidden by the limbus and cannot be seen directly due to total internal reflection. **High-Yield Clinical Pearls for NEET-PG:** * **Image Characteristics:** The image formed in IDOP is **Real, Inverted, and Magnified**. * **Magnification:** It is inversely proportional to the power of the condensing lens. A **20D lens** (most common) gives ~3x magnification, while a 13D lens gives higher magnification (~5x). * **Principle:** It works on the principle of **Convex-lens Ophthalmoscopy**, making the eye highly myopic by placing a strong condensing lens in front of it. * **Advantage:** It provides **stereopsis** (3D view), which is crucial for diagnosing retinal detachment or elevated tumors.

Question 157: What is the earliest ocular manifestation of pregnancy-induced hypertension?

A. Soft Exudates
B. Flame-shaped hemorrhages
C. Constriction of nasal blood vessels (Correct Answer)
D. Papilledema

Explanation: **Explanation:** Pregnancy-Induced Hypertension (PIH), specifically pre-eclampsia, manifests in the eye as a form of hypertensive retinopathy. The primary underlying pathophysiology is **generalized arteriolar vasospasm** caused by increased sensitivity to circulating pressor substances like Angiotensin II. **Why the correct answer is right:** The earliest clinical sign of PIH in the retina is **segmental or generalized narrowing of the arterioles**. This constriction typically begins in the **nasal periphery** before progressing to the posterior pole. Therefore, the constriction of nasal blood vessels is the first detectable change, often preceding systemic symptoms or significant proteinuric changes. **Analysis of incorrect options:** * **A & B (Soft Exudates and Flame-shaped hemorrhages):** These represent more advanced stages of retinopathy. They occur due to focal ischemia and breakdown of the blood-retinal barrier as the hypertension worsens. They are signs of severity, not the initial manifestation. * **D (Papilledema):** This is a late and ominous sign indicating severe pre-eclampsia or eclampsia. It suggests increased intracranial pressure or severe hypertensive encephalopathy and carries a poor prognosis for both the mother and the fetus. **High-Yield Clinical Pearls for NEET-PG:** * **Most common ocular finding in PIH:** Generalized narrowing of retinal arterioles. * **Most common cause of sudden vision loss in PIH:** Serous (Exudative) Retinal Detachment. This is usually bilateral and typically resolves spontaneously after delivery. * **Elschnig spots:** Small, black spots surrounded by a yellow halo; they represent focal infarcts of the choroid and are a sign of hypertensive choroidopathy in severe PIH. * **Management:** The definitive treatment for PIH-related retinal changes is the termination of pregnancy (delivery). Retinal changes usually regress rapidly postpartum.

Question 158: All of the following are true of Eale's disease except?

A. Occurs in the young
B. Vitreous hemorrhage is present
C. Retinal detachment
D. Optic neuritis (Correct Answer)

Explanation: **Explanation:** **Eales’ Disease** is an idiopathic, inflammatory peripheral retinal perivasculitis (primarily affecting the venules) that typically leads to peripheral non-perfusion, neovascularization, and recurrent vitreous hemorrhages. **Why Optic Neuritis is the Correct Answer:** Optic neuritis is an inflammation of the optic nerve, which is **not** a characteristic feature of Eales’ disease. Eales’ disease is primarily a **retinal vascular disease**. While the inflammation can rarely involve the optic disc (papillitis) in severe cases, "Optic Neuritis" is a distinct clinical entity associated with demyelinating diseases like Multiple Sclerosis, not the peripheral vasculitis seen here. **Analysis of Other Options:** * **A. Occurs in the young:** This is true. It characteristically affects healthy young adult males (typically 20–40 years of age). * **B. Vitreous hemorrhage:** This is a hallmark feature. Peripheral retinal ischemia leads to Neovascularization Elsewhere (NVE). These fragile new vessels rupture easily, causing sudden, painless vision loss due to vitreous hemorrhage. * **C. Retinal Detachment:** This is a known complication. Chronic neovascularization leads to fibrovascular proliferation. The contraction of these membranes can cause **Tractional Retinal Detachment (TRD)**, which is a major cause of permanent visual loss in these patients. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Strongly associated with hypersensitivity to **Tuberculoprotein** (Mantoux test is often strongly positive). * **Stages:** Perivasculitis (sheathing) → Peripheral non-perfusion → Neovascularization → Vitreous Hemorrhage/TRD. * **Classic Sign:** "Sea-fan" neovascularization (similar to Sickle Cell Retinopathy). * **Treatment:** Peripheral laser photocoagulation (PRP) for ischemia and Anti-VEGF injections; Vitrectomy for non-clearing hemorrhage or TRD.

Question 159: What is the standard treatment for diabetic retinopathy?

A. Phacoemulsification
B. Retina laser photocoagulation (Correct Answer)
C. LASIK
D. None of the above

Explanation: ### Explanation **Correct Answer: B. Retina laser photocoagulation** **Mechanism and Rationale:** Diabetic Retinopathy (DR) is characterized by retinal ischemia, which triggers the release of **Vascular Endothelial Growth Factor (VEGF)**. This leads to neovascularization (Proliferative DR) and increased capillary permeability (Macular Edema). * **Pan-retinal Photocoagulation (PRP):** This is the gold standard for Proliferative Diabetic Retinopathy (PDR). By destroying the peripheral hypoxic retina, it reduces the overall oxygen demand and decreases VEGF production, leading to the regression of new vessels. * **Focal/Grid Laser:** Historically used for Clinically Significant Macular Edema (CSME) to seal leaking microaneurysms. **Analysis of Incorrect Options:** * **A. Phacoemulsification:** This is the modern surgical technique for **cataract extraction**. While diabetics are prone to early-onset cataracts, this procedure does not treat the underlying retinal pathology. * **C. LASIK:** This is a refractive surgery used to reshape the cornea to correct **myopia, hyperopia, and astigmatism**. It has no role in managing retinal vascular diseases. **High-Yield Clinical Pearls for NEET-PG:** * **First Sign of DR:** Microaneurysms (found in the Inner Nuclear Layer). * **Classification:** Based on the **ETDRS study**. The "4-2-1 rule" is used to diagnose Severe Non-Proliferative DR (NPDR). * **Current Trends:** While laser is the "standard" for PDR, **Intravitreal Anti-VEGF agents** (e.g., Ranibizumab, Bevacizumab) are now the first-line treatment for Diabetic Macular Edema (DME). * **Dot-Blot Hemorrhages:** Located in the Inner Nuclear/Outer Plexiform layers.

Question 160: Fundus examination of a patient presenting with loss of vision revealed a cherry-red spot on the macula. What is the most likely diagnosis?

A. Retinitis pigmentosa
B. Retinoblastoma
C. Central retinal artery occlusion (CRAO) (Correct Answer)
D. Central retinal vein occlusion (CRVO)

Explanation: ### Explanation **Correct Option: C. Central retinal artery occlusion (CRAO)** The hallmark of CRAO is the **"Cherry-Red Spot."** In CRAO, the sudden blockage of the central retinal artery leads to ischemia and intracellular edema of the inner retinal layers, causing the retina to appear milky-white and opaque. However, the fovea is the thinnest part of the retina and lacks these inner layers; thus, the underlying highly vascular **choroid** shines through the thin foveal tissue, creating the characteristic cherry-red appearance against the pale, edematous background. **Incorrect Options:** * **A. Retinitis pigmentosa:** Characterized by the triad of bony-spicule pigmentation, arteriolar attenuation, and waxy disc pallor. It does not present with a cherry-red spot. * **B. Retinoblastoma:** Typically presents with **leukocoria** (white pupillary reflex) and strabismus. While it involves the retina, it does not cause acute arterial occlusion or a cherry-red spot. * **C. Central retinal vein occlusion (CRVO):** Classically described as a **"Blood and Thunder"** fundus, showing extensive flame-shaped hemorrhages, tortuous veins, and disc edema due to venous congestion. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis of Cherry-Red Spot:** Remember the mnemonic **"Sands"** or **"T-C-M-S-G"**: **T**ay-Sachs disease, **C**RAO, **M**ultiple Sclerosis (rarely), **S**andhoff disease, and **G**aucher’s/Niemann-Pick disease. * **Cilioretinal Artery:** In 15–20% of the population, this artery (derived from ciliary circulation) supplies the macula. If present during CRAO, central vision may be preserved. * **Management:** CRAO is an ocular emergency. Immediate measures include digital ocular massage, anterior chamber paracentesis, and inhaled carbogen to lower IOP and dislodge the embolus.

Practice by Chapter

Retinal Anatomy and Physiology

Practice Questions

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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