Diseases of the Retina Practice Questions

Q: Which of the following statements is NOT true regarding Purtscher retinopathy?

Gradual painless loss of vision is typically seen.. **Explanation:** **Purtscher Retinopathy** is a rare, occlusive microangiopathy typically triggered by severe non-ocular trauma or systemic diseases. **1. Why Option B is the Correct Answer (The False Statement):** Purtscher retinopathy is characterized by **sudden, profound, and painless loss of vision** (usually 6/60 or worse) occurring within 24–48 hours of the inciting event. It is an acute vascular event, not a gradual process. The vision loss is typically bilateral but can be asymmetrical. **2. Analysis of Other Options:** * **Option A (Causes):** It is classically associated with **severe head injury**, compressive chest trauma (crush injuries), and **acute pancreatitis**. These conditions lead to the formation of microemboli (leukocyte aggregates, fat, or fibrin) that occlude retinal precapillary arterioles. * **Option C (Clinical Features):** The hallmark signs include **Purtscher flecks** (areas of inner retinal whitening), cotton wool spots, and **multiple retinal hemorrhages** (flame-shaped or dot-blot). * **Option D (Associations):** While trauma is the most common cause, "Purtscher-like retinopathy" is associated with systemic conditions such as **HELLP syndrome**, systemic lupus erythematosus (SLE), and chronic renal failure. **Clinical Pearls for NEET-PG:** * **Pathogenesis:** Embolization leading to precapillary arteriolar occlusion and subsequent retinal ischemia. * **Fundus Findings:** Look for the "Purtscher fleck"—pathognomonic white patches between the retinal arterioles and venules, usually sparing the area immediately adjacent to the vessels. * **Management:** No specific ocular treatment exists; management focuses on treating the underlying systemic cause (e.g., managing pancreatitis). Vision may partially recover over months, but permanent deficits are common.

Q: Ring scotoma is characteristically seen during the progression of which condition?

Retinitis pigmentosa. **Explanation:** **Retinitis Pigmentosa (RP)** is a hereditary dystrophy primarily affecting the rod photoreceptors. The characteristic visual field defect in RP is a **Ring Scotoma**. This occurs because the degeneration typically begins in the mid-periphery of the retina (where rod density is highest). As the disease progresses, these mid-peripheral scotomas coalesce to form a circular (ring) area of vision loss. Eventually, this progresses to "tunnel vision," leaving only a small central island of vision before total blindness. **Analysis of Incorrect Options:** * **Night Blindness (Nyctalopia):** This is a *symptom*, not a disease entity itself. While it is the earliest clinical feature of RP, it describes the inability to see in low light rather than a specific pattern of visual field loss. * **Severe Myopia:** Pathological myopia is associated with peripheral retinal degenerations (like lattice degeneration) and central scotomas (due to Forster-Fuchs spots), but not a characteristic ring scotoma. * **Angle Closure Glaucoma:** This typically presents with sudden, severe pain and vision loss. Chronic glaucoma (POAG) causes arcuate or Bjerrum scotomas, which may eventually lead to tunnel vision, but the classic "ring" progression is specific to RP. **NEET-PG High-Yield Pearls:** * **Classic Triad of RP:** Bony spicule pigmentation, Arteriolar attenuation (narrowing), and Waxy pallor of the optic disc. * **Electroretinogram (ERG):** The most sensitive test for early diagnosis; it shows a reduced or abolished "a" and "b" waves even before fundus changes appear. * **Inheritance:** Most common is Autosomal Recessive; most severe is X-linked. * **Other causes of Ring Scotoma:** Chloroquine toxicity (Bull’s eye maculopathy), Vitamin A deficiency, and Glaucoma (double arcuate scotoma).

Q: In electroretinography, the C-wave is primarily due to which cellular component?

Retinal pigment epithelium. ### Explanation The **Electroretinogram (ERG)** is a diagnostic test that measures the electrical response of the retina to a light stimulus. The waveform consists of several distinct components, each corresponding to specific retinal layers. **1. Why Retinal Pigment Epithelium (RPE) is Correct:** The **C-wave** is a long-latency, positive deflection that follows the b-wave. It is generated by the **Retinal Pigment Epithelium (RPE)** in response to the decrease in potassium concentration in the subretinal space following photoreceptor activation. It reflects the metabolic health of the RPE-photoreceptor complex. **2. Analysis of Incorrect Options:** * **Rods and Cones (Option A):** These generate the **a-wave**, which is the first negative deflection of the ERG. It represents the hyperpolarization of the photoreceptor outer segments. * **Muller Cells and Bipolar Cells (Options B & C):** These are primarily responsible for the **b-wave**, the largest positive deflection. While the b-wave is the result of several interactions, the trans-retinal current generated by Muller cells (secondary to bipolar cell activity) is the major contributor. **3. High-Yield Clinical Pearls for NEET-PG:** * **A-wave:** Negative wave (Photoreceptors). * **B-wave:** Positive wave (Muller/Bipolar cells). It is the most clinically used component. * **C-wave:** Positive wave (RPE). * **D-wave:** Represents the "off-response" of the retina. * **Oscillatory Potentials:** Seen on the rising limb of the b-wave; they represent activity in the **Amacrine cells** and are sensitive indicators of retinal ischemia (e.g., Early Diabetic Retinopathy). * **Arden Index:** Used in **EOG (Electro-oculogram)** to assess RPE function. A value 1.85).

Q: In retinitis pigmentosa, 'night-blindness' is an early symptom of visual loss. Which of the following explains this phenomenon?

Cones are relatively preserved compared to rods. **Explanation:** **1. Why Option B is Correct:** Retinitis Pigmentosa (RP) is a hereditary dystrophy characterized by the progressive degeneration of photoreceptors. The primary pathology begins in the **rods**, which are concentrated in the mid-periphery of the retina and are responsible for scotopic (low-light) vision. Because rods are affected first and more severely than cones, the earliest clinical symptom is **nyctalopia (night blindness)**. Cones, which handle photopic (daylight) and central vision, are relatively preserved in the early stages, allowing patients to maintain good visual acuity until the disease progresses to the macula. **2. Why Other Options are Incorrect:** * **Options A & C:** Ganglion cells are the third-order neurons in the visual pathway. While they may eventually undergo secondary degeneration in advanced RP, they are not the primary site of pathology. The hallmark of RP is a "photoreceptor-first" degeneration. * **Option D:** While it is true that ganglion cells are relatively preserved compared to rods, this does not explain the specific symptom of *night blindness*. Night blindness is specifically a result of the functional disparity between the two types of photoreceptors (rods vs. cones). **3. High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Most common is Autosomal Recessive; most severe is X-linked. * **Classic Triad (Fundus):** 1. Arteriolar attenuation (narrowing). 2. Bony spicule pigmentation (mid-periphery). 3. Waxy pallor of the optic disc. * **Visual Field:** Characteristically shows a **ring scotoma**, which progresses to "tunnel vision." * **Electroretinogram (ERG):** The most sensitive test for early diagnosis; shows a **reduced or extinguished 'a' and 'b' wave** (scotopic response affected first). * **Associations:** Usher syndrome (deafness), Laurence-Moon-Biedl syndrome (obesity, polydactyly, hypogonadism).

Q: Retinal detachment occurs between which layers of the retina?

Sensory and pigmentary layer. **Explanation:** In **Retinal Detachment (RD)**, the separation occurs at the **potential space** between the **Neurosensory Retina (NSR)** and the **Retinal Pigment Epithelium (RPE)**. **Why the correct answer is right:** Embryologically, the retina develops from the optic cup. The outer layer of the cup forms the RPE, while the inner layer forms the neurosensory retina. These two layers never fuse firmly; they are held together by the pump action of the RPE and the interdigitation of photoreceptors. When fluid (subretinal fluid) accumulates in this potential space, it separates the sensory retina from its underlying pigmentary layer, leading to RD. **Why the incorrect options are wrong:** * **Options A, B, and D:** These describe separations between the internal layers of the neurosensory retina itself. Separation within these layers is characteristic of **Retinoschisis** (splitting of the retinal layers), not retinal detachment. Specifically, the most common site for degenerative retinoschisis is the outer plexiform layer. **High-Yield Clinical Pearls for NEET-PG:** * **Most common type:** Rhegmatogenous RD (caused by a break/hole in the retina). * **Most common site of a retinal break:** Superotemporal quadrant. * **Classic Symptoms:** Photopsia (flashes of light), sudden onset of floaters, and a "curtain-like" loss of vision. * **Shafer’s Sign:** Presence of "tobacco dust" (pigment cells) in the anterior vitreous; it is pathognomonic for a retinal tear. * **Treatment:** The goal is to close the break. Modalities include Scleral buckling, Pneumatic retinopexy, or Pars Plana Vitrectomy (PPV).

Q: A 32-year-old male presents with unilateral diminished vision in the right eye. On examination, there is mild iritis, vitritis, and a focal necrotic lesion seen at the macula. What is the most likely diagnosis?

Ocular toxoplasmosis. **Explanation:** The clinical presentation of a **focal necrotic retinochoroiditis** associated with inflammatory signs like **iritis** and **vitritis** (often described as a "headlight in the fog" appearance) is a classic hallmark of **Ocular Toxoplasmosis**. 1. **Why Ocular Toxoplasmosis is correct:** It is the most common cause of posterior uveitis worldwide. In young adults, it typically presents as a unilateral, focal, yellowish-white necrotic lesion. The intense vitreous inflammatory reaction (vitritis) overlying the lesion is a key diagnostic feature. While often a reactivation of a congenital infection (near an old pigmented scar), primary acquired cases also present with active necrotizing retinitis. 2. **Why other options are incorrect:** * **Multiple Evanescent White Dot Syndrome (MEWDS):** Typically presents with multiple, very small, fine white dots at the level of the RPE/deep retina. It lacks the intense vitritis and large focal necrotic lesions seen here. * **Multifocal Choroiditis (MFC):** Characterized by multiple, small, punched-out chorioretinal lesions (similar to Histoplasmosis) but with associated vitritis. It does not typically present as a single large focal necrotic macular lesion. * **Ocular Sarcoidosis:** Usually presents with bilateral granulomatous uveitis, "mutton-fat" keratic precipitates, and "string of pearls" vitreous opacities or retinal periphlebitis (candle-wax drippings), rather than a focal necrotic retinal lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Sign:** "Headlight in the fog" (Active retinitis seen through dense vitritis). * **Treatment of Choice:** Triple therapy (Pyrimethamine, Sulfadiazine, and Folinic acid) + Steroids (Steroids are *never* given without anti-parasitic cover). * **Macula involvement:** Toxoplasmosis has a predilection for the posterior pole, making it a common cause of permanent central vision loss.

Q: The 'Sea-Fan' appearance of the retina is characteristic of which condition?

Sickle cell disease. **Explanation:** The **'Sea-fan' appearance** refers to characteristic neovascularization (new vessel growth) seen in **Sickle Cell Retinopathy**, specifically in the proliferative stage. **1. Why Sickle Cell Disease is correct:** In Sickle Cell Disease (most commonly the SC and S-Thal genotypes), sickled erythrocytes cause microvascular occlusion in the peripheral retinal arterioles. This leads to peripheral ischemia, which triggers the release of Vascular Endothelial Growth Factor (VEGF). This results in **Proliferative Sickle Retinopathy (PSR)**, where new vessels grow in a fan-shaped pattern resembling the marine invertebrate *Gorgonia flabellum* (Sea-fan). These vessels usually arise from arteriovenous anastomoses at the junction of the vascular and avascular retina. **2. Why other options are incorrect:** * **CRAO:** Characterized by a **'Cherry-red spot'** at the macula due to retinal edema and opacification, with the underlying choroid shining through the thin fovea. * **SLE:** Typically presents with **Cotton wool spots** (cytoid bodies) and retinal vasculitis, but does not classically produce sea-fan neovascularization. * **Gaucher’s Disease:** May show small, white, well-defined spots (preretinal glia) or cherry-red spots in rare types, but not peripheral neovascularization. **High-Yield Clinical Pearls for NEET-PG:** * **Goldberg’s Classification:** Used to stage Sickle Cell Retinopathy (Stage III is the Sea-fan stage). * **Salmon-patch hemorrhage:** A pre-proliferative sign (intraretinal hemorrhage). * **Black sunburst:** Areas of RPE hypertrophy/pigmentation following the resorption of a hemorrhage. * **Differential for Sea-fan:** Eales disease, ROP, and Branch Retinal Vein Occlusion (BRVO) can also occasionally show similar patterns, but it is most classic for Sickle Cell.

Q: Retinal detachment in Eale's disease is typically which type?

Tractional RD. **Explanation:** **Eales’ Disease** is an idiopathic inflammatory peripheral perivasculitis (primarily affecting the venules) that leads to peripheral retinal ischemia and neovascularization. **Why Tractional RD is the correct answer:** The hallmark of Eales’ disease is peripheral retinal neovascularization (sea-fan neovascularization). These new vessels are accompanied by fibrous proliferation. As this fibrovascular membrane contracts, it exerts mechanical pull on the retina, leading to a **Tractional Retinal Detachment (TRD)**. This is the most common type of RD seen in the proliferative stage of the disease, similar to the mechanism in Proliferative Diabetic Retinopathy (PDR). **Why other options are incorrect:** * **Exudative RD:** While Eales’ disease involves inflammation and vascular leakage, the primary sight-threatening complication in advanced stages is due to fibrosis and traction, not massive subretinal fluid accumulation. * **Rhegmatogenous RD:** This is caused by a retinal break or tear. While a tractional detachment can occasionally lead to a secondary tear (Tractional-Rhegmatogenous), it is not the primary or typical mechanism in Eales’ disease. **Clinical Pearls for NEET-PG:** * **Demographics:** Typically affects young adult males (20–40 years). * **Association:** Strongly associated with hypersensitivity to **Tuberculoprotein** (Mantoux test is often positive). * **Presentation:** Sudden painless loss of vision most commonly due to **Vitreous Hemorrhage** (the most common complication). * **Stages:** Perivasculitis (sheathing) → Peripheral Ischemia → Neovascularization → Vitreous Hemorrhage/Tractional RD. * **Treatment:** Laser photocoagulation for ischemia; Vitrectomy for non-resolving vitreous hemorrhage or TRD.

Question 1

A 62-year-old poorly controlled diabetic presents with sudden painless loss of vision. There is no history of floaters. He also complains of a visual field defect which has been progressively worsening over the past few months. He has a history of similar complaints in the other eye, for which vitrectomy was performed. What is the next step in management?

Accepted Answer

Pars plana vitrectomy

Answer

Pan-retinal photocoagulation

Answer

Scleral buckling

Answer

Pneumatic retinopexy

Question 2

Which of the following statements is NOT true regarding Purtscher retinopathy?

Accepted Answer

Gradual painless loss of vision is typically seen.

Answer

Head injury and pancreatic injury are common causes.

Answer

Multiple retinal hemorrhages are observed.

Answer

It can be associated with HELLP syndrome.

Question 3

Vitreous hemorrhage is commonly caused by which of the following conditions?

Accepted Answer

Retinal vein occlusion

Answer

Retinal artery occlusion

Answer

Retinitis pigmentosa

Answer

Retinoblastoma

Question 4

Ring scotoma is characteristically seen during the progression of which condition?

Accepted Answer

Retinitis pigmentosa

Answer

Night blindness

Answer

Severe myopia

Answer

Angle closure glaucoma

Question 5

In electroretinography, the C-wave is primarily due to which cellular component?

Accepted Answer

Retinal pigment epithelium

Answer

Rods and cones

Answer

Muller cells

Answer

Bipolar cells

Question 6

In retinitis pigmentosa, 'night-blindness' is an early symptom of visual loss. Which of the following explains this phenomenon?

Accepted Answer

Cones are relatively preserved compared to rods

Answer

Cones are relatively preserved compared to ganglion cells

Answer

Ganglion cells are relatively preserved compared to cones

Answer

Ganglion cells are relatively preserved compared to rods

Question 7

Retinal detachment occurs between which layers of the retina?

Accepted Answer

Sensory and pigmentary layer

Answer

Sensory and nuclear layer

Answer

Inner nuclear layer and outer nuclear layer

Answer

Outer plexiform and inner plexiform layer

Question 8

A 32-year-old male presents with unilateral diminished vision in the right eye. On examination, there is mild iritis, vitritis, and a focal necrotic lesion seen at the macula. What is the most likely diagnosis?

Accepted Answer

Ocular toxoplasmosis

Answer

Multiple evanescent white dot syndrome

Answer

Multifocal choroiditis

Answer

Ocular sarcoidosis

Question 9

The 'Sea-Fan' appearance of the retina is characteristic of which condition?

Accepted Answer

Sickle cell disease

Answer

Central retinal artery occlusion (CRAO)

Answer

Systemic lupus erythematosus (SLE)

Answer

Gaucher's disease

Question 10

Retinal detachment in Eale's disease is typically which type?

Accepted Answer

Tractional RD

Answer

Exudative RD

Answer

Rhegmatogenous RD

Answer

All of the above

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

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