Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 341: Macular involvement is common in which of the following conditions?

A. Toxoplasma (Correct Answer)
B. Malaria
C. CMV
D. Syphilis

Explanation: Explanation: Toxoplasmosis (caused by Toxoplasma gondii) is the most common cause of posterior uveitis worldwide. The hallmark lesion is a focal necrotizing retinochoroiditis. The parasite has a high predilection for the macula (central retina), often resulting in a "punched-out" pigmented scar once healed. In congenital cases, bilateral macular scars are a classic finding, leading to significant permanent vision loss. The active lesion adjacent to an old scar is famously described as the "Headlight in the fog" appearance due to overlying vitreous haze. Why other options are incorrect: * Malaria: Ocular involvement is rare. While "Malarial Retinopathy" (vessel whitening, hemorrhages) can occur in severe cerebral malaria, it is not a primary or common cause of macular-specific inflammatory lesions. * CMV (Cytomegalovirus): Typically seen in immunocompromised patients (AIDS). It causes a fulminant necrotizing retinitis described as "Pizza-pie" or "Cottage cheese and ketchup" appearance. It follows the vascular arcades and spreads peripherally; while it can involve the macula, it is not as characteristically "macula-predominant" as Toxoplasma. * Syphilis: Known as the "Great Imitator," it can cause any form of uveitis (disseminated or multifocal), but it does not have the same specific predilection for the macula as Toxoplasma. High-Yield Clinical Pearls for NEET-PG: * Toxoplasmosis: Most common cause of posterior uveitis; Macula is the site of predilection. * Treatment of choice: Triple therapy (Pyrimethamine + Sulfadiazine + Folinic acid) + Steroids. * Congenital Toxoplasmosis Triad: Chorioretinitis, Hydrocephalus, and Intracranial calcifications. * CMV Retinitis: Most common ocular opportunistic infection in AIDS (CD4 count <50 cells/µL).

Question 342: Cotton wool spots in hypertensive retinopathy are found in which layer of the retina?

A. Retinal pigment epithelium
B. Nerve fibre layer (Correct Answer)
C. Ganglionic cell layer
D. Internal limiting membrane

Explanation: **Explanation:** **Why the Nerve Fibre Layer (NFL) is correct:** Cotton wool spots (CWS), also known as soft exudates, are not true exudates. They represent **micro-infarctions** of the retinal nerve fibre layer. When precapillary arterioles are occluded (due to hypertension, diabetes, or other vasculitides), axoplasmic flow within the nerves is interrupted. This leads to the accumulation of transported organelles and debris, creating "cytoid bodies" that appear clinically as fluffy, white, cloud-like opacities in the **Nerve Fibre Layer**. **Analysis of Incorrect Options:** * **Retinal Pigment Epithelium (RPE):** This is the outermost layer. Pathology here typically involves drusen or pigmentary changes (e.g., Elschnig spots in hypertensive choroidopathy), not CWS. * **Ganglionic Cell Layer:** While adjacent to the NFL, this layer contains the cell bodies. CWS specifically involve the axons (fibres) of these cells. * **Internal Limiting Membrane (ILM):** This is the innermost basement membrane separating the retina from the vitreous. It does not contain the neural tissue required to form cytoid bodies. **High-Yield Clinical Pearls for NEET-PG:** * **Grading:** Cotton wool spots signify **Grade III Hypertensive Retinopathy** (Keith-Wagener-Barker classification). * **Histology:** The pathognomonic histological feature of a CWS is the **Cytoid Body** (swollen axonal ends). * **Hard vs. Soft Exudates:** Unlike CWS (soft exudates), **Hard Exudates** are composed of lipid/lipoprotein deposits and are located in the **Outer Plexiform Layer**. * **Differential Diagnosis:** CWS are also commonly seen in Diabetic Retinopathy, HIV retinopathy, and Retinal Vein Occlusions.

Question 343: Vitreous hemorrhage is not seen in which of the following conditions?

A. Hypertension
B. Eales' disease
C. Trauma
D. Vitreous degeneration (Correct Answer)

Explanation: **Explanation:** Vitreous hemorrhage (VH) occurs when blood extravasates into the vitreous cavity, typically due to the rupture of normal retinal vessels (trauma/vascular stress) or fragile new vessels (neovascularization). **Why Vitreous Degeneration is the Correct Answer:** Vitreous degeneration (such as synchysis scintillans or asteroid hyalosis) involves the liquefaction of the vitreous gel or the deposition of calcium/lipid salts. While **Posterior Vitreous Detachment (PVD)**—a form of degeneration—can *lead* to a hemorrhage if it causes a retinal tear, pure vitreous degeneration itself is a degenerative process of the vitreous matrix and does not involve bleeding. Therefore, it is the least likely cause among the options. **Analysis of Incorrect Options:** * **Hypertension:** Severe or malignant hypertension can lead to retinal flame-shaped hemorrhages and breakthrough bleeding into the vitreous cavity. * **Eales' Disease:** This is an idiopathic peripheral perivasculitis (common in young males) characterized by peripheral non-perfusion and neovascularization. Recurrent vitreous hemorrhage is a hallmark clinical feature of this disease. * **Trauma:** Both blunt and penetrating ocular trauma are leading causes of VH due to the direct rupture of retinal or choroidal vessels. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of VH:** Proliferative Diabetic Retinopathy (PDR). * **Most common cause of VH in young adults:** Trauma or Eales' disease. * **Clinical Sign:** Patients complain of a "sudden shower of floaters" or painless loss of vision. On Ophthalmoscopy, the red reflex is absent or dull. * **Management:** If the fundus is not visible, **B-Scan Ultrasonography** is the investigation of choice to rule out retinal detachment.

Question 344: All are features of early retinal detachment except?

A. Retroorbital pain (Correct Answer)
B. Photopsia
C. Floaters
D. Darkened peripheral field of vision

Explanation: **Explanation:** The correct answer is **Retroorbital pain** because Rhegmatogenous Retinal Detachment (RRD) is a **painless** condition. The retina lacks sensory pain fibers; therefore, the separation of the neurosensory retina from the retinal pigment epithelium does not trigger a pain response. If a patient presents with sudden vision loss accompanied by pain, clinicians should instead suspect conditions like acute angle-closure glaucoma, optic neuritis, or uveitis. **Analysis of Incorrect Options:** * **Photopsia (B):** These are subjective flashes of light caused by mechanical vitreoretinal traction on the retina. As the vitreous pulls on the retina during the early stages of a tear or detachment, it stimulates the photoreceptors, which the brain interprets as light. * **Floaters (C):** These appear as moving spots or "cobwebs" in the field of vision. In early detachment, they are often caused by vitreous syneresis, condensed vitreous fibers, or a "Shafer’s sign" (tobacco dusting), which represents liberated RPE cells in the vitreous. * **Darkened peripheral field (D):** Often described by patients as a "curtain or shadow" falling over the vision, this occurs as the subretinal fluid accumulates and the detached retina ceases to function in that specific area. **High-Yield Clinical Pearls for NEET-PG:** * **Shafer’s Sign:** The presence of pigment cells in the anterior vitreous is pathognomonic for a retinal tear. * **Configuration:** RRD typically presents with a convex, opaque, and corrugated appearance of the retina with loss of choroidal pattern. * **Marcus-Gunn Pupil (RAPD):** This may be present if the retinal detachment is extensive or involves the macula. * **Primary Risk Factors:** High myopia (axial length >26.5mm), aphakia, and lattice degeneration.

Question 345: Diagnosis of CMV retinitis is primarily by?

A. Fundoscopy (Correct Answer)
B. Retinal biopsy
C. CMV DNA detection
D. ELISA

Explanation: **Explanation:** **CMV Retinitis** is the most common opportunistic ocular infection in patients with AIDS (typically when CD4 counts fall below 50 cells/µL). **Why Fundoscopy is the correct answer:** The diagnosis of CMV retinitis is primarily **clinical**, based on its characteristic appearance during a dilated funduscopic examination. The classic findings are so distinct that laboratory confirmation is rarely required for initiation of treatment. The two main patterns seen are: 1. **"Pizza-pie" or "Cottage cheese and ketchup" appearance:** Characterized by fluffy yellow-white retinal opacification (necrosis) with prominent intraretinal hemorrhages. 2. **Granular/Indolent pattern:** Peripheral granular opacities with little to no hemorrhage. **Why other options are incorrect:** * **Retinal Biopsy:** This is an invasive procedure with high morbidity. It is reserved only for atypical cases that fail to respond to standard therapy. * **CMV DNA detection (PCR):** While PCR of aqueous or vitreous humor is highly sensitive and specific, it is not the primary diagnostic tool. It is used as an adjunct in diagnostically challenging cases. * **ELISA:** Serum antibody testing (IgG/IgM) is of little value because CMV is a ubiquitous virus; a positive result indicates previous exposure but does not confirm active retinal disease. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of involvement:** Along the major retinal vascular arches. * **Leading cause of blindness in AIDS:** CMV Retinitis (due to retinal detachment or optic nerve involvement). * **Treatment of choice:** Intravenous **Ganciclovir**. Alternatives include Valganciclovir, Foscarnet, and Cidofovir. * **Key differentiator:** Unlike Toxoplasmosis, CMV retinitis presents with minimal vitreous inflammation ("cold" endophthalmitis).

Question 346: The Resse Ellsworth classification is used for which of the following conditions?

A. Hypertensive retinopathy
B. Optic nerve glioma
C. Retinoblastoma (Correct Answer)
D. Choroidal melanoma

Explanation: **Explanation:** The **Reese-Ellsworth classification** was historically the primary system used for **Retinoblastoma** (Option C). It was specifically designed to predict the likelihood of **prognosis for globe salvage** (saving the eye) following external beam radiotherapy. It categorizes tumors into five groups (Group I to V) based on tumor size, number, and location (e.g., behind or anterior to the equator). While the Reese-Ellsworth system is still high-yield for exams, modern clinical practice has largely shifted to the **International Classification of Intraocular Retinoblastoma (ICIR)**, which better predicts success with modern treatments like systemic or intra-arterial chemotherapy. **Analysis of Incorrect Options:** * **A. Hypertensive Retinopathy:** Uses the **Keith-Wagener-Barker** classification (Stages I-IV) or the Mitchell-Wong classification. * **B. Optic Nerve Glioma:** Typically associated with Neurofibromatosis Type 1; it does not use the Reese-Ellsworth system. * **D. Choroidal Melanoma:** Staged using the **TNM classification** or categorized by size (Small, Medium, Large) according to the **COMS** (Collaborative Ocular Melanoma Study). **Clinical Pearls for NEET-PG:** * **Most common intraocular malignancy in children:** Retinoblastoma. * **Most common presenting sign:** Leukocoria (White pupillary reflex), followed by strabismus. * **Pathognomonic Histology:** Flexner-Wintersteiner rosettes. * **Genetics:** Mutation in the **RB1 gene** on chromosome **13q14**. * **Calcification:** A hallmark feature seen on CT scans (helps differentiate from Coats' disease).

Question 347: Which of the following is NOT of prognostic significance in choroidal melanoma?

A. Presence of retinal detachment (Correct Answer)
B. Size of the tumor
C. Cytology of the tumor cells
D. Presence of extraocular extension

Explanation: In the management of **Choroidal Melanoma**, the most common primary intraocular malignancy in adults, prognosis is determined by the tumor's potential for systemic metastasis (primarily to the liver). ### **Why "Presence of Retinal Detachment" is the correct answer:** Exudative retinal detachment is a very common **clinical feature** of choroidal melanoma caused by fluid leakage from the tumor vessels. While it causes significant vision loss, its presence does **not** correlate with the metastatic potential or the survival rate of the patient. Therefore, it is not a prognostic factor. ### **Explanation of Incorrect Options (Prognostic Factors):** * **Size of the Tumor (B):** This is one of the most critical clinical predictors. Larger tumors (measured by basal diameter and height) have a significantly higher risk of metastasis compared to small tumors. * **Cytology of the Tumor Cells (C):** Based on the **Callender Classification**, cell type is a major prognostic indicator. **Spindle A** cells have the best prognosis, while **Epithelioid** cells (large, polygonal cells) carry the worst prognosis and highest mortality. * **Extraocular Extension (D):** If the tumor has breached the sclera and extended into the orbit, the prognosis becomes significantly worse due to the increased likelihood of hematogenous spread. ### **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of metastasis:** Liver (90% of cases). * **Genetic Prognosticator:** **Monosomy 3** is the most important chromosomal marker for poor prognosis (high metastatic risk). * **Histopathology:** The presence of "closed vascular loops" (microvascular patterns) is a poor prognostic sign. * **Investigation of Choice:** **B-Scan Ultrasonography** (shows "Hollow" internal reflectivity and "Choroidal excavation"). * **Treatment:** Small/Medium tumors are often treated with **Plaque Brachytherapy**; large tumors or those with optic nerve involvement require **Enucleation**.

Question 348: Angioid streaks occur in which of the following conditions?

A. Sturge-Weber's syndrome
B. Sickle cell disease (Correct Answer)
C. Pseudoexfoliation syndrome
D. Septo-optic dysplasia

Explanation: **Explanation:** **Angioid streaks** are jagged, radiating cracks in a thickened, calcified, and brittle **Bruch’s membrane**. They typically emanate from the optic disc and resemble blood vessels (hence "angioid"), but are actually dehiscences in the elastic lamina of Bruch's membrane. **Why Sickle Cell Disease is Correct:** Sickle cell disease (and other hemoglobinopathies like Thalassemia) is a classic systemic association. The underlying mechanism involves chronic hemolysis leading to iron deposition (hemosiderosis) in Bruch’s membrane, which increases its brittleness and leads to the characteristic linear streaks. **Analysis of Incorrect Options:** * **Sturge-Weber Syndrome:** Characterized by "tomato ketchup" fundus due to diffuse choroidal hemangiomas, not Bruch’s membrane pathology. * **Pseudoexfoliation Syndrome:** A systemic condition involving the deposition of fibrillar material in the anterior segment (lens capsule, iris), primarily leading to secondary open-angle glaucoma. * **Septo-optic Dysplasia (De Morsier Syndrome):** A congenital malformation involving optic nerve hypoplasia and midline brain defects; it does not involve retinal streaks. **High-Yield Clinical Pearls (NEET-PG):** To remember the major causes of Angioid Streaks, use the mnemonic **PEPSI**: * **P:** **P**seudoxanthoma elasticum (Most common association; "plucked chicken" skin appearance). * **E:** **E**hlers-Danlos syndrome. * **P:** **P**aget’s disease of the bone. * **S:** **S**ickle cell disease / Thalassemia. * **I:** **I**diopathic. **Clinical Significance:** The most vision-threatening complication of angioid streaks is the development of **Choroidal Neovascularization (CNVM)**, which can lead to subretinal hemorrhage and permanent central vision loss.

Question 349: The "pizza pie" appearance of the retina is characteristic of which of the following conditions?

A. Toxoplasmosis
B. Congenital rubella
C. Drug toxicity
D. CMV retinitis (Correct Answer)

Explanation: **Explanation:** **CMV Retinitis (Correct Answer):** Cytomegalovirus (CMV) retinitis is the most common opportunistic ocular infection in patients with AIDS (typically when CD4 counts fall below 50 cells/mm³). The characteristic **"Pizza Pie"** or **"Cottage cheese and ketchup"** appearance refers to the fundoscopic finding of dense, white perivascular retinal opacification (representing necrosis and edema) interspersed with prominent retinal hemorrhages. It typically spreads along the retinal vessels in a "brushfire" pattern. **Analysis of Incorrect Options:** * **Toxoplasmosis:** Characteristically presents as a **"Headlight in the fog"** appearance, which refers to an active yellowish-white fluffy lesion (retinitis) seen through a hazy vitreous caused by intense vitritis. * **Congenital Rubella:** Classically associated with a **"Salt and pepper" retinopathy**, characterized by diffuse, mottled pigmentary changes in the retinal pigment epithelium (RPE), usually without affecting vision significantly. * **Drug Toxicity:** Various drugs cause specific patterns (e.g., Chloroquine/Hydroxychloroquine causes **"Bull’s eye maculopathy"**; Thioridazine causes "nummular" pigmentary changes), but none present with the hemorrhagic necrotic pattern of CMV. **High-Yield Clinical Pearls for NEET-PG:** * **Treatment of Choice:** Intravenous **Ganciclovir** (or Valganciclovir). Foscarnet and Cidofovir are alternatives. * **Frosted Branch Angiitis:** Another clinical variant of CMV retinitis characterized by severe perivascular sheathing. * **Key differentiator:** Unlike Toxoplasmosis, CMV retinitis typically presents with **minimal vitritis** ("cold" endophthalmitis) because the patient is severely immunocompromised.

Question 350: All of the following take part in the pathogenesis of macular edema in diabetic retinopathy except?

A. Retinal pigment epithelium dysfunction (Correct Answer)
B. Oxidative stress
C. VEGF
D. Increased protein kinase–C

Explanation: **Explanation:** Diabetic Macular Edema (DME) is primarily a result of the breakdown of the **Blood-Retinal Barrier (BRB)**. While the BRB consists of both an inner (retinal vascular endothelium) and an outer (Retinal Pigment Epithelium - RPE) component, the pathogenesis of DME is almost exclusively driven by changes in the **inner blood-retinal barrier**. * **Why Option A is Correct:** In diabetic retinopathy, the primary insult occurs at the level of the retinal capillaries (microangiopathy). While the RPE may be affected in late-stage degenerative diseases (like AMD), **RPE dysfunction is not a primary driver** of the fluid accumulation seen in diabetic macular edema. Instead, it is the leakage from retinal microaneurysms and damaged capillaries that overwhelms the compensatory mechanisms. * **Why the other options are incorrect:** * **VEGF (Vascular Endothelial Growth Factor):** This is the central mediator in DME. Hyperglycemia induces VEGF, which increases vascular permeability by phosphorylating tight junction proteins (like occludin). * **Protein Kinase-C (PKC):** Hyperglycemia activates the PKC pathway (specifically the β isoform), which leads to basement membrane thickening, endothelial proliferation, and increased vascular permeability. * **Oxidative Stress:** Chronic hyperglycemia leads to the formation of Advanced Glycation End-products (AGEs) and reactive oxygen species, which cause pericyte loss and endothelial damage. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest clinical sign** of Diabetic Retinopathy: Microaneurysms (in the inner nuclear layer). * **Earliest pathological sign:** Loss of pericytes. * **Gold Standard for diagnosing DME:** Optical Coherence Tomography (OCT) – shows increased central macular thickness. * **First-line treatment for DME:** Intravitreal Anti-VEGF agents (e.g., Ranibizumab, Aflibercept).

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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