Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 101: All are macular function tests except?

A. Colour Vision
B. Visual acuity
C. Entoptic phenomenon
D. Scanning laser polarimetry (Correct Answer)

Explanation: **Explanation:** The macula is responsible for central vision, high-resolution visual acuity, and color perception. Macular function tests are clinical investigations used to assess the functional integrity of the macula, especially when the media (cornea or lens) is opaque. **Why Scanning Laser Polarimetry (SLP) is the correct answer:** Scanning Laser Polarimetry (e.g., GDx) is not a functional test but a **structural imaging modality**. It uses polarized light to measure the thickness of the **Retinal Nerve Fiber Layer (RNFL)** based on the principle of birefringence. It is primarily used for the early diagnosis and monitoring of **Glaucoma**, not for assessing macular function. **Analysis of Incorrect Options:** * **Visual Acuity:** This is the most basic test of macular function, assessing the fovea's ability to resolve fine detail. * **Colour Vision:** The cones are densely packed in the fovea centralis. Testing color vision (e.g., Ishihara charts) is a sensitive indicator of macular health. * **Entoptic Phenomenon:** These are visual perceptions caused by the eye's own internal structures. Examples include **Blue Field Entoptoscopy** (to visualize macular capillary circulation) and the **Maxwell spot**, both used to assess macular viability behind cataracts. **Clinical Pearls for NEET-PG:** * **Other Macular Function Tests:** Amsler Grid (detects metamorphopsia), Photostress test (recovery time >50-60s is abnormal), Contrast sensitivity, and Potential Acuity Meter (PAM). * **Electrophysiology:** The **mfERG (Multifocal Electroretinogram)** is the specific electrophysiological test for macular function, whereas the standard ERG reflects global retinal activity. * **Watzke-Allen Test:** A clinical test using a slit lamp beam to confirm a Full-Thickness Macular Hole (FTMH).

Question 102: Which condition is associated with HLA-A29?

A. Serpiginous geographical choroidopathy
B. Birdshot retinochoroidopathy (Correct Answer)
C. Sympathetic ophthalmitis
D. Acute posterior multifocal placoid pigment epitheliopathy

Explanation: **Explanation:** **Birdshot Retinochoroidopathy (BSRC)** is the correct answer because it has the strongest known association between a disease and an HLA haplotype in all of medicine. Approximately **95–97% of patients** with BSRC are positive for **HLA-A29**. It is a chronic, bilateral posterior uveitis characterized by multiple cream-colored, oval spots (resembling birdshot from a shotgun) scattered throughout the fundus, primarily in the post-equatorial region. **Analysis of Incorrect Options:** * **A. Serpiginous geographical choroidopathy:** This is a chronic, progressive inflammatory disease of the choriocapillaris and RPE. While it has some associations with HLA-B7, it is not linked to HLA-A29. * **C. Sympathetic ophthalmitis:** This is a bilateral granulomatous panuveitis following penetrating trauma or surgery to one eye. It is most commonly associated with **HLA-DR4** and HLA-DQw3, not HLA-A29. * **D. Acute posterior multifocal placoid pigment epitheliopathy (APMPPE):** This is a self-limiting condition characterized by multiple cream-colored placoid lesions. It is associated with **HLA-B7 and HLA-DR2**, often following a viral prodrome. **NEET-PG High-Yield Pearls:** * **The "A29" Rule:** If you see HLA-A29 in a question, the answer is almost always Birdshot Retinochoroidopathy. * **Clinical Presentation:** Patients typically present with floaters and blurred vision; the hallmark is the "birdshot" pattern of lesions that spare the macula initially. * **Investigation:** Indocyanine Green (ICG) angiography is superior to Fluorescein Angiography (FA) for visualizing the deep choroidal lesions. * **Treatment:** Requires long-term systemic immunosuppression (e.g., Cyclosporine) to prevent vision loss from cystoid macular edema (CME).

Question 103: Cherry red spot is seen in all except?

A. Niemann-Pick's disease
B. Tay-Sachs disease
C. Gaucher's disease
D. Sarcoidosis (Correct Answer)

Explanation: **Explanation:** The **Cherry Red Spot** is a classic ophthalmic finding where the fovea appears bright red against a pale, opacified background of the surrounding retina. This occurs because the fovea is the thinnest part of the retina and lacks the ganglion cell layer; therefore, the underlying vascular choroid shines through, while the surrounding retina becomes opaque due to ischemia or the accumulation of metabolic storage material in the ganglion cells. **Why Sarcoidosis is the correct answer:** Sarcoidosis is a multisystem granulomatous disease. In the eye, it typically presents with **uveitis** (granulomatous), "mutton-fat" keratic precipitates, and "candle-wax drippings" (periphlebitis). It does **not** cause storage of metabolites in the ganglion cell layer or acute retinal artery occlusion, and thus does not produce a cherry red spot. **Analysis of Incorrect Options:** * **Tay-Sachs Disease:** A GM2 gangliosidosis (hexosaminidase A deficiency) where lipids accumulate in retinal ganglion cells, causing the characteristic pale halo around the fovea. * **Niemann-Pick Disease:** A sphingomyelinase deficiency leading to sphingomyelin accumulation. It is a classic cause of a cherry red spot (seen in 50% of Type A cases). * **Gaucher’s Disease:** While less common than the others, the **infantile form (Type 2)** can present with a cherry red spot due to glucosylceramide accumulation. **NEET-PG High-Yield Pearls:** * **Most common cause:** Central Retinal Artery Occlusion (CRAO). * **Mnemonic for Cherry Red Spot (CHERRY):** **C**RAO, **H**allervorden-Spatz syndrome, **E**nzymatic deficiency (Tay-Sachs, Farber’s), **R**etinal trauma (Berlin’s edema), **R**etinal toxicity (Quinine), **Y**oung (Sialidosis/Gaucher's/Niemann-Pick). * **Differential:** In **Tay-Sachs**, the spot is always present; in **CRAO**, the spot disappears after a few weeks as retinal atrophy sets in.

Question 104: Which of the following statements regarding Retinopathy of Prematurity is true?

A. It is classified in 4 stages based on severity.
B. Most cases resolve spontaneously. (Correct Answer)
C. Based on anatomical location, Zone 3 includes the nasal retina.
D. Polyhydramnios is a risk factor.

Explanation: **Explanation:** **Retinopathy of Prematurity (ROP)** is a vasoproliferative disorder affecting the immature retina of preterm infants. 1. **Why Option B is Correct:** The majority of infants with ROP (approximately 80–90%) develop only mild stages (Stage 1 or 2) that undergo **spontaneous regression** without requiring any medical or surgical intervention. Only a small percentage progress to "Threshold Disease" or retinal detachment requiring treatment. 2. **Why Other Options are Incorrect:** * **Option A:** ROP is classified into **5 stages** based on severity (Stage 1: Demarcation line to Stage 5: Total retinal detachment), not 4. * **Option C:** Based on anatomical location, **Zone 1** is centered on the disc, **Zone 2** extends to the nasal ora serrata, and **Zone 3** is the remaining **temporal crescent** of the retina. Zone 3 does *not* include the nasal retina. * **Option D:** The primary risk factors are **low birth weight (<1500g)**, **low gestational age (<32 weeks)**, and **unmonitored oxygen therapy**. Polyhydramnios is not a recognized risk factor for ROP. **High-Yield Clinical Pearls for NEET-PG:** * **Plus Disease:** Characterized by venous dilation and arterial tortuosity in the posterior pole; it indicates active, aggressive disease. * **Screening Timing:** The first screening should be done at **4 weeks post-natal age** or **31 weeks post-conceptional age** (whichever is later). * **Treatment of Choice:** Laser photocoagulation (diode laser) of the peripheral avascular retina is the gold standard. Anti-VEGF agents (e.g., Ranibizumab) are increasingly used for Zone 1 disease.

Question 105: What is the most common cause of gradual vision loss in Diabetic Retinopathy?

A. Cataract
B. Macular edema (Correct Answer)
C. Glaucoma
D. Keratoconus

Explanation: **Explanation:** In Diabetic Retinopathy (DR), visual impairment occurs through two primary mechanisms: **gradual** loss and **sudden** loss. **1. Why Macular Edema is Correct:** Diabetic Macular Edema (DME) is the **most common cause of gradual, painless vision loss** in patients with both Non-Proliferative (NPDR) and Proliferative Diabetic Retinopathy (PDR). Chronic hyperglycemia leads to a breakdown of the blood-retinal barrier, causing fluid leakage and lipid exudation (Hard Exudates) into the macula. This thickening of the central retina distorts the foveal architecture, leading to a progressive decline in visual acuity. **2. Analysis of Incorrect Options:** * **Cataract (A):** While diabetics are prone to developing cataracts earlier (snowflake cataracts), it is a secondary complication and not the primary retinal cause of vision loss in DR. * **Glaucoma (C):** Neovascular Glaucoma (NVG) can occur in advanced PDR due to rubeosis iridis, but this typically presents with pain and acute vision loss rather than the classic gradual decline seen with DME. * **Keratoconus (D):** This is a corneal ectasia unrelated to the pathophysiology of Diabetic Retinopathy. **3. NEET-PG High-Yield Pearls:** * **Most common cause of sudden vision loss in DR:** Vitreous Hemorrhage. * **First clinical sign of DR:** Microaneurysms (seen in the Inner Nuclear Layer). * **Earliest pathological change:** Loss of Pericytes and basement membrane thickening. * **Investigation of choice for DME:** Optical Coherence Tomography (OCT) is used to quantify macular thickness; Fundus Fluorescein Angiography (FFA) identifies the source of leakage. * **Treatment Gold Standard for DME:** Intravitreal Anti-VEGF injections (e.g., Ranibizumab, Bevacizumab).

Question 106: Cotton wool spots are seen in which of the following conditions?

A. Diabetic retinopathy, Hypertensive retinopathy, AIDS, Toxemia of pregnancy (Correct Answer)
B. Diabetic retinopathy, Hypertensive retinopathy, AIDS, Retinoblastoma
C. Diabetic retinopathy, AIDS, Retinoblastoma, Toxemia of pregnancy
D. Diabetic retinopathy, Hypertensive retinopathy, Retinoblastoma, Toxemia of pregnancy

Explanation: **Explanation:** **Cotton wool spots (CWS)**, also known as soft exudates, are not true exudates. They represent **focal areas of retinal ischemia** in the nerve fiber layer (NFL). The underlying mechanism involves the obstruction of precapillary arterioles, leading to the cessation of axoplasmic flow in the ganglion cell axons. This causes "axoplasmic stasis" and the accumulation of organelles, which appear clinically as fluffy, white, cloud-like lesions with indistinct margins. **Why Option A is Correct:** CWS are a hallmark of retinal microvascular compromise. They are classically seen in: * **Diabetic Retinopathy:** Indicative of the pre-proliferative stage (NPDR). * **Hypertensive Retinopathy:** Specifically Grade III (Modified Scheie Classification). * **AIDS:** The most common clinical sign of HIV retinopathy (non-infectious). * **Toxemia of Pregnancy (Preeclampsia/Eclampsia):** Resulting from severe arteriolar vasospasm. * Other causes include retinal vein occlusion, systemic lupus erythematosus (SLE), and severe anemia. **Why Other Options are Incorrect:** Options B, C, and D include **Retinoblastoma**. Retinoblastoma is a primary intraocular malignancy of childhood characterized by a "chalky white" mass due to dystrophic calcification, not CWS. While both appear white on fundoscopy, their pathophysiology is entirely different; CWS are ischemic markers, whereas Retinoblastoma is a neoplastic growth. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** CWS correspond to **Cytoid bodies** (swollen ends of ruptured axons) in the nerve fiber layer. * **Location:** They are always found in the **posterior pole** because the NFL is thickest there. * **Rule of Thumb:** The presence of >8 CWS in a diabetic patient is a strong predictor of progression to Proliferative Diabetic Retinopathy (PDR). * **HIV Retinopathy:** CWS are the most common finding and must be differentiated from CMV retinitis (which shows "pizza-pie" hemorrhages and necrosis).

Question 107: Examination of the fundus shows a cherry-red spot in all of the following conditions, EXCEPT:

A. Gaucher's disease
B. Tay-Sachs disease
C. Niemann-Pick disease
D. Central retinal vein occlusion (Correct Answer)

Explanation: **Explanation:** The **cherry-red spot** is a clinical sign where the fovea appears bright red against a pale, edematous background. This occurs because the fovea is the thinnest part of the retina, lacking the ganglion cell layer. When the surrounding retina becomes opaque (due to ischemia or metabolic storage), the underlying vascular choroid shines through at the fovea, creating the "red spot" appearance. **Why Central Retinal Vein Occlusion (CRVO) is the correct answer:** In CRVO, there is a backup of blood due to venous obstruction, leading to widespread retinal hemorrhages, tortuous veins, and disc edema (the **"Blood and Thunder"** fundus). It does **not** cause a cherry-red spot. A cherry-red spot is characteristic of Central Retinal *Artery* Occlusion (CRAO), where sudden ischemia causes retinal whitening. **Analysis of incorrect options:** * **Tay-Sachs & Niemann-Pick Disease:** These are Lysosomal Storage Disorders (Sphingolipidoses). Accumulation of lipids (Gangliosides and Sphingomyelin, respectively) in the retinal ganglion cells causes the surrounding retina to appear white, highlighting the red fovea. * **Gaucher’s Disease:** While rare, a cherry-red spot can be seen in the perinatal/infantile forms of Gaucher’s due to glucosylceramide accumulation. **NEET-PG High-Yield Pearls:** * **Mnemonic for Cherry-Red Spot:** "**S**andhoff's, **T**ay-Sachs, **R**etinal Artery Occlusion, **I**nfantile Gaucher's, **N**iemann-Pick, **G**angliosidosis (GM1)." (**STRING**) * **CRAO:** The most common cause of a cherry-red spot in adults. * **Tay-Sachs:** The most common cause in children. * **Quinine Poisoning:** An important toxicological cause of a cherry-red spot.

Question 108: Which of the following is NOT seen in Central Retinal Artery (CRA) occlusion?

A. Gradual loss of vision (Correct Answer)
B. Headache
C. Sudden loss of vision
D. Retained central vision

Explanation: **Explanation:** **Central Retinal Artery Occlusion (CRAO)** is a true ophthalmic emergency, often referred to as an "ocular stroke." **Why "Gradual loss of vision" is the correct answer:** CRAO is characterized by an **abrupt, painless, and profound loss of vision** (typically counting fingers to light perception). Because the central retinal artery is an end-artery, its occlusion leads to immediate ischemic necrosis of the inner retinal layers. **Gradual** vision loss is characteristic of conditions like cataracts, open-angle glaucoma, or age-related macular degeneration, not acute vascular occlusions. **Analysis of Incorrect Options:** * **Sudden loss of vision:** This is the hallmark clinical presentation of CRAO. * **Headache:** While not a primary symptom of the occlusion itself, CRAO is frequently associated with **Giant Cell Arteritis (GCA)** in elderly patients. In such cases, patients often present with a new-onset headache, jaw claudication, and scalp tenderness. * **Retained central vision:** This occurs in approximately 15–25% of the population who possess a **Cilioretinal artery** (a branch of the posterior ciliary artery). If this artery is present, the macular area remains perfused despite CRAO, sparing central visual acuity. **High-Yield Clinical Pearls for NEET-PG:** * **Fundus Findings:** "Cherry-red spot" at the fovea (due to the thin fovea showing the underlying choroid) and "cattle-track" appearance of retinal vessels. * **Ground Glass Appearance:** The retina appears milky-white due to intracellular edema. * **Management:** Immediate ocular massage, anterior chamber paracentesis, and inhalation of Carbogen (95% $O_2$, 5% $CO_2$) to induce vasodilation. * **Most common cause:** Embolism (usually from the carotid artery or heart).

Question 109: Which of the following statements about asteroid hyalosis is false?

A. Consists of calcium bodies in the vitreous cavity.
B. Is a degenerative condition of the eye.
C. Is typically unilateral. (Correct Answer)
D. All of the above.

Explanation: **Explanation:** Asteroid hyalosis is a common, benign vitreoretinal condition characterized by the presence of numerous tiny, white, spherical bodies (asteroid bodies) suspended in the vitreous humor. **Why Option C is the correct answer (False statement):** Asteroid hyalosis is **typically unilateral** (occurring in one eye) in approximately **75% to 90%** of cases. The statement "Is typically bilateral" (implied as the false statement in this context) or the choice provided as the "false" one indicates that its unilateral nature is its hallmark clinical feature. In the context of this question, if the option "Is typically unilateral" is marked as the correct answer to "which is false," it suggests a common examiner trap where students confuse it with Synchysis Scintillans (which is often bilateral and associated with trauma). *Note: In clinical practice, asteroid hyalosis is indeed mostly unilateral; if the question asks for the false statement, it implies the condition is usually bilateral, which is incorrect.* **Analysis of other options:** * **Option A (True):** Asteroid bodies are composed of **calcium-lipid complexes** (hydroxyapatite) suspended within the vitreous fibrils. * **Option B (True):** It is considered a **degenerative condition**, usually associated with aging (typically seen in patients over 60). It is generally asymptomatic and does not significantly affect vision. **NEET-PG High-Yield Pearls:** * **Appearance:** "Stars in a night sky" or "Snowstorm" appearance on ophthalmoscopy. * **Mobility:** Unlike Synchysis Scintillans, asteroid bodies move with vitreous displacement but **return to their original position** because they are attached to the vitreous framework. * **Associations:** Often linked with Diabetes Mellitus, Hypertension, and Hypercholesterolemia (though evidence is debated). * **Diagnosis:** If the fundus is obscured, **B-scan ultrasonography** shows bright, mobile echoes with a clear vitreous space behind them.

Question 110: Which of the following is a characteristic sign of diabetic retinopathy?

A. Increase in pericytes
B. Thinned out capillary basement membrane
C. Lipohyaline deposits
D. Proliferation of endothelial cells (Correct Answer)

Explanation: ### Explanation The hallmark of diabetic retinopathy (DR) is microangiopathy, characterized by structural and cellular changes in the retinal capillaries. **Why the Correct Answer is Right:** In diabetic retinopathy, the chronic hyperglycemic state leads to the **proliferation of endothelial cells**. This occurs as a compensatory response to capillary non-perfusion and hypoxia. The proliferation, along with basement membrane thickening, leads to narrowing of the capillary lumen, further exacerbating retinal ischemia. This process eventually triggers the release of VEGF (Vascular Endothelial Growth Factor), leading to neovascularization (Proliferative Diabetic Retinopathy). **Analysis of Incorrect Options:** * **A. Increase in pericytes:** This is incorrect. One of the earliest pathognomonic changes in DR is the **loss of pericytes** (pericyte ghost cells). Pericytes normally provide structural support and regulate endothelial cell growth; their loss leads to out-pouching of the capillary wall (microaneurysms). * **B. Thinned out capillary basement membrane:** This is incorrect. In diabetes, there is actually **thickening of the capillary basement membrane** due to the accumulation of type IV collagen and glycation end-products. * **C. Lipohyaline deposits:** While hyaline degeneration occurs in systemic hypertension and diabetes (arteriolosclerosis), it is not the primary characteristic sign used to describe the microvascular cellular dynamics of diabetic retinopathy in this context. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Clinical Sign:** Microaneurysms (seen as red dots in the inner nuclear layer). * **Earliest Pathological Change:** Basement membrane thickening and pericyte loss (Pericyte:Endothelial ratio changes from 1:1 to 1:0). * **Cotton Wool Spots:** Represent nerve fiber layer infarcts (pre-proliferative stage). * **Hard Exudates:** Composed of lipoproteins/lipid-laden macrophages in the Outer Plexiform Layer (Henle’s layer in the macula).

Practice by Chapter

Retinal Anatomy and Physiology

Practice Questions

Age-Related Macular Degeneration

Practice Questions

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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