Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 21: Malignant melanoma of the choroid will produce which of the following?

A. Retinal dialysis
B. Exudative retinal detachment (Correct Answer)
C. Traction retinal detachment
D. Rhegmatogenous retinal detachment

Explanation: ### Explanation **Malignant Melanoma of the Choroid** is the most common primary intraocular malignancy in adults. The correct answer is **Exudative Retinal Detachment (ERD)**. #### Why Exudative Retinal Detachment is Correct: Choroidal melanoma is a solid subretinal tumor. As the tumor grows, it disrupts the overlying Retinal Pigment Epithelium (RPE) and the blood-retinal barrier. This leads to the leakage of fluid (exudate) from the tumor vessels and the damaged choriocapillaris into the subretinal space. Because this fluid accumulation occurs without a retinal break or mechanical pulling, it is classified as an **exudative (secondary) retinal detachment**. A classic clinical sign is "shifting fluid," where the detachment moves based on the patient's head position. #### Why Other Options are Incorrect: * **Retinal Dialysis:** This is a linear tear at the ora serrata, usually caused by blunt ocular trauma. It leads to rhegmatogenous detachment, not solid tumors. * **Traction Retinal Detachment (TRD):** This occurs when fibrovascular membranes in the vitreous pull the retina away (e.g., Proliferative Diabetic Retinopathy). Melanomas do not typically create these contractile forces. * **Rhegmatogenous Retinal Detachment (RRD):** This requires a full-thickness retinal break (hole or tear) allowing liquefied vitreous to enter the subretinal space. While a tumor can occasionally cause a secondary tear, the primary mechanism is always exudative. #### High-Yield Clinical Pearls for NEET-PG: * **Most common site:** Posterior pole (Choroid). * **Diagnosis:** **B-Scan Ultrasonography** is the gold standard, showing a "collar-stud" or **mushroom-shaped** appearance and **acoustic shadowing** (excavation of the choroid). * **Fluorescein Angiography (FFA):** Shows a "double circulation" pattern (simultaneous staining of retinal and tumor vessels). * **Treatment:** Small tumors are managed with plaque brachytherapy; large or painful tumors require enucleation. * **Metastasis:** Most commonly spreads to the **Liver** (hematogenous spread).

Question 22: In central serous retinopathy, what occurs in the macular region?

A. Spontaneous detachment of neuro-sensory retina (Correct Answer)
B. Macular oedema
C. Detachment of pigment epithelium
D. Detachment of choroid

Explanation: **Explanation:** **Central Serous Retinopathy (CSR)** is characterized by the accumulation of transparent fluid in the subretinal space, leading to a **spontaneous, circumscribed detachment of the neurosensory retina** at the macula. 1. **Why Option A is Correct:** The primary pathology in CSR involves a defect in the pumping function of the Retinal Pigment Epithelium (RPE) or choroidal hyperpermeability. This leads to fluid leakage from the choriocapillaris through the RPE, pooling under the neurosensory retina and lifting it up. 2. **Why Options B, C, and D are Incorrect:** * **Macular Oedema (B):** This refers to intraretinal fluid (within the retinal layers), whereas CSR involves subretinal fluid (between the RPE and neurosensory retina). * **Detachment of Pigment Epithelium (C):** While a small Pigment Epithelial Detachment (PED) often co-exists and may be the "source" of the leak, the hallmark clinical feature and the cause of visual symptoms in CSR is the overlying neurosensory detachment. * **Detachment of Choroid (D):** CSR is a disease of the outer retina and RPE; the choroid remains attached to the sclera. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Typically affects young to middle-aged males with **"Type A" personalities** or those on **steroid therapy**. * **Clinical Features:** Sudden onset of painless blurred vision, **metamorphopsia** (distorted vision), and **micropsia** (objects appearing smaller). * **Diagnosis:** * **FFA (Fundus Fluorescein Angiography):** Shows characteristic **"Ink-blot"** or **"Smokestack"** appearance. * **OCT:** Gold standard for confirming subretinal fluid and monitoring resolution. * **Management:** Most cases are self-limiting and resolve spontaneously within 3–4 months. Conservative management is preferred initially.

Question 23: Choroidal neovascularization is seen in all of the following conditions except?

A. Trauma
B. Angioid streaks
C. Myopia
D. Hypermetropia (Correct Answer)

Explanation: ### Explanation **Choroidal Neovascularization (CNV)** occurs when new, fragile blood vessels grow from the choroid through defects in **Bruch’s membrane** into the sub-retinal space. The key pathophysiological requirement for CNV is a mechanical or degenerative break in Bruch’s membrane. **Why Hypermetropia is the Correct Answer:** Hypermetropia (farsightedness) is characterized by a shorter axial length of the eyeball. Unlike high myopia, it does not involve stretching or thinning of the retinal layers or Bruch’s membrane. Therefore, it is **not** associated with the development of CNV. **Analysis of Incorrect Options:** * **Trauma:** Blunt trauma can cause **Choroidal Rupture** (typically concentric to the optic disc). These mechanical tears in Bruch’s membrane are a classic precursor to late-onset CNV. * **Angioid Streaks:** These are crack-like dehiscences in a calcified, brittle Bruch’s membrane. They are associated with the mnemonic **PEPSI** (Pseudoxanthoma elasticum, Ehlers-Danlos, Paget’s disease, Sickle cell anemia, Idiopathic). CNV is a frequent and vision-threatening complication. * **Myopia:** Pathological myopia (high myopia) leads to axial elongation, causing "lacquer cracks" (linear breaks in Bruch’s membrane). This is a leading cause of CNV in young adults (Myopic CNV). **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of CNV:** Age-related Macular Degeneration (Wet/Exudative AMD). * **Investigation of Choice:** **Optical Coherence Tomography (OCT)** is used for screening/monitoring, but **Fluorescein Angiography (FFA)** is the gold standard to confirm the type of CNV (Classic vs. Occult). * **Treatment:** Intravitreal **Anti-VEGF** agents (e.g., Ranibizumab, Bevacizumab, Aflibercept) are the first-line management. * **Metamorphopsia:** The earliest symptom of CNV, best monitored using an **Amsler Grid**.

Question 24: All of the following are causes of sudden painless loss of vision except?

A. Central retinal artery occlusion
B. Optic atrophy (Correct Answer)
C. Optic neuritis
D. Retinal detachment

Explanation: To approach this question, one must distinguish between **sudden** (seconds to days) and **gradual** (months to years) vision loss. ### Why Optic Atrophy is the Correct Answer **Optic Atrophy** is the end-stage result of various optic nerve pathologies. It represents the degeneration of retinal ganglion cell axons. This process is inherently **chronic and progressive**, leading to a **gradual, painless** loss of vision. It does not occur overnight; therefore, it does not fit the "sudden" criteria. ### Analysis of Incorrect Options (Causes of Sudden Painless Loss) * **Central Retinal Artery Occlusion (CRAO):** Characterized by "amaurosis fugax" or sudden, profound, painless loss of vision (seconds to minutes). Clinical hallmark: **Cherry-red spot** at the macula. * **Optic Neuritis:** Typically presents as sudden/subacute vision loss. While often associated with pain on ocular movement (90% of cases), it can occasionally be painless. However, compared to the chronic nature of optic atrophy, it is classified as a sudden cause. * **Retinal Detachment (RD):** Rhegmatogenous RD causes sudden, painless vision loss, often preceded by "flashes and floaters" (photopsia) and a "curtain-falling" sensation in the visual field. ### NEET-PG Clinical Pearls * **Sudden Painless Loss of Vision (Mnemonic: "CRV"):** **C**RAO, **R**etinal Detachment, **V**itreous Hemorrhage, and Central Retinal **V**ein Occlusion (CRVO). * **Sudden Painful Loss of Vision:** Acute Congestive Glaucoma, Endophthalmitis, and Uveitis. * **Gradual Painless Loss of Vision:** Cataract, Refractive errors, Glaucoma (POAG), and **Optic Atrophy**. * **High-Yield Fact:** The most common cause of a "Cherry-red spot" is CRAO, but in children, consider metabolic storage diseases like Tay-Sachs.

Question 25: Vexin vein invasion is a feature of which of the following conditions?

A. Malignant melanoma (Correct Answer)
B. Retinoblastoma
C. Medulloepithelioma
D. Optic nerve glioma

Explanation: **Explanation:** **Malignant Melanoma** of the choroid is the most common primary intraocular malignancy in adults. One of its hallmark pathological features is its mode of extraocular extension. The tumor cells frequently invade the **vortex veins** (often referred to as "vexin veins" in some older texts or exam transcripts) as they exit the sclera. This venous invasion is a critical prognostic factor, as it facilitates hematogenous spread, most commonly to the liver. **Why other options are incorrect:** * **Retinoblastoma:** This is the most common intraocular tumor in children. Its primary mode of spread is via direct extension through the **optic nerve** to the subarachnoid space or via the sclera into the orbit, rather than specific vortex vein invasion. * **Medulloepithelioma:** A rare tumor arising from the non-pigmented ciliary epithelium. It is typically locally invasive within the anterior segment and does not characteristically involve the vortex veins. * **Optic Nerve Glioma:** This is a benign (pilocytic astrocytoma) or low-grade tumor of the optic nerve associated with Neurofibromatosis Type 1. It spreads along the optic nerve sheath toward the chiasm, not through the uveal venous system. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of metastasis for Choroidal Melanoma:** Liver (95% of cases). * **Pathological Classification:** Callender’s classification (Spindle A, Spindle B, and Epithelioid cells). **Epithelioid cells** have the worst prognosis. * **Collar-stud (Mushroom) appearance:** A classic sign on B-scan USG when the tumor breaks through Bruch’s membrane. * **Investigation of choice:** Standardized A-scan (shows low internal reflectivity) and B-scan USG.

Question 26: What is the characteristic feature of diabetic retinopathy?

A. Hard exudate
B. Soft exudate
C. Amblyopia
D. Microaneurysm (Correct Answer)

Explanation: **Explanation:** **Microaneurysms** are the **earliest clinically detectable sign** and the hallmark feature of Diabetic Retinopathy (DR). Pathologically, they occur due to the loss of intramural pericytes, leading to focal outpouchings of the retinal capillary walls. On fundoscopy, they appear as tiny, round, red dots, typically located in the inner nuclear layer. On Fluorescein Angiography (FFA), they appear as "pinpoint leaks" (hyperfluorescence). **Analysis of Incorrect Options:** * **A. Hard Exudates:** These are yellowish-waxy deposits of lipids and proteins in the outer plexiform layer. While common in Non-Proliferative Diabetic Retinopathy (NPDR), they are a result of chronic vascular leakage rather than the primary diagnostic hallmark. * **B. Soft Exudates (Cotton Wool Spots):** These represent focal areas of retinal ischemia (infarction of the nerve fiber layer). They are seen in pre-proliferative DR and other conditions like hypertensive retinopathy, but are not the pathognomonic feature. * **C. Amblyopia:** This is a functional reduction in vision due to abnormal visual development (e.g., strabismus or refractive errors), usually in childhood. It is not a feature of diabetic retinopathy, which causes vision loss through macular edema or vitreous hemorrhage. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Pathological Change:** Basement membrane thickening and pericyte loss (Pericyte:Endothelial cell ratio changes from 1:1 to 1:0). * **First Clinical Sign:** Microaneurysms. * **IRMA (Intraretinal Microvascular Abnormalities):** A hallmark of "Severe NPDR." * **Neovascularization (NVD/NVE):** The defining feature that differentiates Proliferative (PDR) from Non-Proliferative (NPDR) retinopathy. * **Most Common Cause of Vision Loss in DR:** Diabetic Macular Edema (DME).

Question 27: Retinal tears are most commonly seen in which type of retinal detachment?

A. Primary retinal detachment (Correct Answer)
B. Secondary retinal detachment
C. Tractional retinal detachment
D. Exudative retinal detachment

Explanation: **Explanation:** **Primary Retinal Detachment**, also known as **Rhegmatogenous Retinal Detachment (RRD)**, is characterized by the presence of a break (tear or hole) in the neurosensory retina. The term "Rhegmatogenous" is derived from the Greek word *rhegma*, meaning a break. In this condition, liquefied vitreous passes through the retinal tear into the subretinal space, separating the neurosensory retina from the underlying retinal pigment epithelium (RPE). This is the most common type of clinical retinal detachment. **Why other options are incorrect:** * **Tractional Retinal Detachment:** Caused by the pulling of the retina by fibrovascular membranes (common in Proliferative Diabetic Retinopathy). While tears *can* occur secondary to traction, the primary mechanism is the physical pulling, not a pre-existing tear. * **Exudative (Serous) Retinal Detachment:** Occurs due to the accumulation of fluid under the retina without any retinal break. It is usually caused by inflammation (e.g., VKH syndrome) or tumors (e.g., Choroidal melanoma). * **Secondary Retinal Detachment:** This is a broad category referring to detachments caused by underlying pathologies like tumors or systemic diseases, rather than a primary retinal break. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for retinal tears:** Superotemporal quadrant. * **Most common precursor lesion:** Lattice degeneration (seen in ~8% of the general population). * **Classic Symptoms:** Photopsia (flashing lights), sudden onset of floaters (Muscae volitantes), and a "curtain-like" loss of vision. * **Shafer’s Sign:** Presence of "tobacco dust" (pigment cells) in the anterior vitreous is pathognomonic for a retinal tear.

Question 28: Retinoblastoma arises from which layer of the retina?

A. Layer of rods and cones
B. Layer of bipolar cells
C. Ganglion cells layer
D. Any nucleated retinal layer (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Any nucleated retinal layer** **Underlying Medical Concept:** Retinoblastoma is a primary intraocular malignancy of childhood that originates from **multipotent neuroepithelial cells** (primitive retinal cells). These precursor cells are found in all **nucleated layers** of the sensory retina. While historically there was debate regarding its exact cell of origin, it is now established that the tumor can arise from any layer containing nuclei, specifically the **Inner Nuclear Layer (INL)**, the **Outer Nuclear Layer (ONL)**, and the **Ganglion Cell Layer (GCL)**. The tumor is characterized by the proliferation of undifferentiated cells that may show differentiation toward photoreceptor elements (forming Flexner-Wintersteiner rosettes). **Why Incorrect Options are Wrong:** * **A, B, and C:** These options (Rods/Cones, Bipolar cells, and Ganglion cells) are specific components of the retinal layers. While retinoblastoma *can* arise from these layers, selecting any one of them is too restrictive. Since the primitive neuroectodermal cells are distributed across all cellular (nucleated) strata of the retina, "Any nucleated retinal layer" is the most accurate and comprehensive description. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Mutation in the **RB1 gene** on chromosome **13q14**. It follows Knudson’s "Two-hit hypothesis." * **Most Common Sign:** **Leukocoria** (White pupillary reflex), followed by strabismus. * **Pathognomonic Histology:** **Flexner-Wintersteiner rosettes** (highly specific); Homer-Wright rosettes (less specific, also seen in neuroblastoma). * **Calcification:** Intraocular calcification in a child under 3 years is retinoblastoma until proven otherwise (visible on CT/Ultrasound). * **Classification:** The **International Classification of Retinoblastoma (ICRB)** is currently used for grouping (Groups A-E) to predict the likelihood of eye salvage.

Question 29: Lacquer cracks in pathological myopia are due to breaks in which layer?

A. Retinal pigment epithelium
B. Bruch's membrane (Correct Answer)
C. Outer plexiform layer
D. Inner plexiform layer

Explanation: **Explanation:** **Lacquer cracks** are a hallmark clinical feature of **pathological myopia** (high myopia). They represent spontaneous, linear, or stellate breaks in **Bruch’s membrane**. 1. **Why Bruch’s membrane is correct:** In pathological myopia, the progressive elongation of the globe (increased axial length) leads to mechanical stretching of the posterior pole. Bruch’s membrane is a relatively inelastic structure; when the stretching exceeds its tensile strength, it develops linear dehiscences or "cracks." These appear clinically as fine, irregular, yellowish-white horizontal lines deep to the retina. 2. **Why the other options are wrong:** * **Retinal Pigment Epithelium (RPE):** While the RPE may undergo secondary atrophy or thinning over a lacquer crack, the primary anatomical break occurs in Bruch's membrane. * **Outer and Inner Plexiform Layers:** These are neural layers of the retina. Breaks here would represent retinoschisis or retinal holes, not the characteristic linear lesions seen in lacquer cracks. **Clinical Pearls for NEET-PG:** * **Significance:** Lacquer cracks are a major risk factor for the development of **Myopic Choroidal Neovascularization (CNV)**, as they provide a pathway for vessels to grow from the choroid into the sub-retinal space. * **Forster-Fuchs Spot:** A pigmented, circular lesion at the macula caused by a healed CNV or subretinal hemorrhage associated with lacquer cracks. * **Other Pathological Myopia findings:** Posterior staphyloma (pathognomonic), tilted disc, and peripheral lattice degeneration.

Question 30: Appreciation of color is a function of which photoreceptor cells in the retina?

A. Rods
B. Cones (Correct Answer)
C. Both rods and cones
D. Neither rods nor cones

Explanation: **Explanation:** The retina contains two primary types of photoreceptor cells: **Rods** and **Cones**. The appreciation of color is exclusively a function of the **Cones**. **1. Why Cones are correct:** Cones are concentrated in the fovea centralis and are responsible for **photopic vision** (vision in bright light), high visual acuity, and **color perception**. There are three types of cones, each containing a different photopigment (iodopsin) sensitive to specific wavelengths: * **L-cones:** Red (Long wavelength) * **M-cones:** Green (Medium wavelength) * **S-cones:** Blue (Short wavelength) The brain integrates signals from these three types to perceive the full visible spectrum (Trichromatic theory). **2. Why other options are incorrect:** * **Rods:** These are responsible for **scotopic vision** (vision in dim light) and peripheral vision. They contain a single pigment, **rhodopsin**, which cannot differentiate between wavelengths. Therefore, rods provide achromatic (black and white) vision. * **Both rods and cones:** While both are photoreceptors, their functions are distinct. Rods do not contribute to color discrimination. * **Neither:** Photoreceptors are the only cells in the retina capable of converting light into electrical signals for color processing. **Clinical Pearls for NEET-PG:** * **Nyctalopia (Night blindness):** Result of rod dysfunction (e.g., Vitamin A deficiency or Retinitis Pigmentosa). * **Color Blindness:** Most commonly an X-linked recessive disorder due to the absence of one or more cone pigments (Protanopia = Red, Deuteranopia = Green, Tritanopia = Blue). * **Ishihara Charts:** The most common screening tool for red-green color blindness. * **Purkinje Shift:** The shift in peak sensitivity from the yellow-red spectrum (cones) to the blue-green spectrum (rods) as light levels drop.

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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