Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 211: Cystoid macular edema develops commonly after which procedure?

A. Extracapsular lens extraction
B. Intracapsular lens extraction (Correct Answer)
C. Proliferative diabetic retinopathy
D. Uveitis

Explanation: **Explanation:** **Cystoid Macular Edema (CME)**, specifically known as **Irvine-Gass Syndrome** when occurring post-cataract surgery, is characterized by the accumulation of fluid in the outer plexiform (Henle’s) and inner nuclear layers of the retina. **Why Intracapsular Lens Extraction (ICCE) is the correct answer:** While CME can occur after any intraocular surgery, it is significantly more common after **ICCE** compared to modern techniques. In ICCE, the entire lens capsule is removed, leading to the loss of the anatomical barrier between the anterior and posterior segments. This results in: 1. **Vitreous Wick Syndrome:** Vitreous incarceration in the wound. 2. **Increased Prostaglandin Release:** Without the posterior capsule, inflammatory mediators diffuse more easily to the macula, increasing capillary permeability. **Analysis of Incorrect Options:** * **Extracapsular Lens Extraction (ECCE/Phacoemulsification):** While CME still occurs, the incidence is much lower (approx. 1–2% clinically significant) because the posterior capsule remains intact, acting as a barrier to inflammatory mediators and preventing vitreous loss. * **Proliferative Diabetic Retinopathy (PDR):** While diabetes causes macular edema, it is typically due to chronic microvascular leakage (Diabetic Macular Edema) rather than the classic "cystoid" pattern seen post-surgically. * **Uveitis:** Inflammatory conditions (like Pars Planitis) are a major cause of CME, but statistically, the historical incidence following ICCE was higher and more characteristic in a surgical context. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Gold standard is **Fluorescein Angiography (FFA)**, showing a characteristic **"Flower-petal appearance"** due to leakage in Henle’s layer. * **OCT Findings:** Shows intraretinal cystic spaces and increased macular thickness. * **Treatment:** First-line treatment involves topical **NSAIDs** (e.g., Nepafenac or Ketorolac) and steroids. * **Spontaneous Resolution:** Most cases of Irvine-Gass syndrome resolve spontaneously within 6 months.

Question 212: Choroidal vascularization is seen in which of the following refractive errors?

A. Myopia (Correct Answer)
B. Hypermetropia
C. Presbyopia
D. Astigmatism

Explanation: **Explanation:** **Choroidal Neovascularization (CNV)** is a hallmark complication of **Pathological Myopia** (typically defined as refractive error > -6.00D or axial length > 26.5 mm). 1. **Why Myopia is correct:** In high myopia, the progressive elongation of the eyeball leads to mechanical stretching and thinning of the retina, choroid, and sclera. This stress causes linear breaks in the **Bruch’s membrane**, known as **Lacquer cracks**. These cracks act as conduits, allowing new, fragile blood vessels from the choroid to grow into the subretinal space (CNV). A classic clinical sign associated with this is the **Fuchs’ Spot**—a pigmented lesion at the macula representing a scarred CNV. 2. **Why other options are incorrect:** * **Hypermetropia:** The eyeball is shorter than normal. While it is associated with conditions like angle-closure glaucoma, it does not involve the mechanical stretching of the posterior pole required for CNV. * **Presbyopia:** This is an age-related physiological loss of accommodation due to decreased elasticity of the crystalline lens; it does not involve structural changes to the retina or choroid. * **Astigmatism:** This is a refractive error caused by an irregular curvature of the cornea or lens and does not predispose the patient to choroidal vascular pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Fuchs’ Spot:** A pigmented, circular lesion at the macula following a subretinal hemorrhage in high myopia. * **Lacquer Cracks:** Mechanical breaks in Bruch’s membrane; they are the strongest precursor to myopic CNV. * **Treatment of choice:** Intravitreal **Anti-VEGF** (e.g., Ranibizumab, Bevacizumab) is the gold standard for managing myopic CNV. * **Other associations of High Myopia:** Posterior staphyloma, Rhegmatogenous Retinal Detachment (RRD), and Lattice degeneration.

Question 213: All of the following are differential diagnoses for cotton wool spots in the fundus except?

A. AIDS
B. Diabetic retinopathy
C. Hypertension
D. Eales' disease (Correct Answer)

Explanation: **Explanation:** **Cotton Wool Spots (CWS)**, also known as soft exudates, represent localized areas of retinal ischemia. They occur due to the obstruction of precapillary arterioles, leading to the failure of axoplasmic transport within the nerve fiber layer (NFL) and subsequent accumulation of "cytoid bodies." **Why Eales' Disease is the correct answer:** Eales' disease is an idiopathic peripheral inflammatory veno-occlusive disease (perivasculitis). Its hallmark features are peripheral retinal neovascularization, recurrent vitreous hemorrhage, and tractional retinal detachment. While it involves ischemia, it primarily affects the peripheral venous system rather than the precapillary arterioles of the posterior pole where CWS are typically observed. Therefore, CWS are not a characteristic feature of Eales' disease. **Analysis of incorrect options:** * **AIDS:** CWS are the most common clinical finding in HIV retinopathy, caused by microvascular injury or direct viral infection of the endothelium. * **Diabetic Retinopathy:** CWS are a classic feature of Pre-proliferative Diabetic Retinopathy (PPDR), signifying significant retinal ischemia. * **Hypertension:** CWS are a hallmark of Grade III Modified Scheie/Keith-Wagener-Barker classification of hypertensive retinopathy. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for CWS (PANIC):** **P**apilledema, **A**IDS, **N**ormal tension glaucoma, **I**schemia (Diabetes/HTN), **C**ollagen vascular diseases (SLE). * **Cytoid Bodies:** These are the histological equivalent of cotton wool spots. * **Purtscher’s Retinopathy:** Characterized by multiple CWS and hemorrhages following severe head or chest trauma. * **Eales' Disease:** Most commonly affects young adult males; strongly associated with hypersensitivity to tuberculoprotein (Mantoux positive).

Question 214: Fluorescein angiography of a patient shows 'Bull's eye' lesions on the retina. Bull's eye retinopathy is due to what?

A. Infrared light
B. UV-light
C. Phenothiazines (Correct Answer)
D. NSAIDS

Explanation: **Explanation:** **Bull’s eye maculopathy** is a classic clinical finding characterized by a central ring of retinal pigment epithelium (RPE) atrophy surrounding a spared central foveal area, giving it a target-like appearance on fundoscopy and fluorescein angiography (FA). **Why Phenothiazines are correct:** Phenothiazines, particularly **Thioridazine** and **Chlorpromazine**, are antipsychotic medications known to cause pigmentary retinopathy. Thioridazine, in high doses (typically >800mg/day), binds to the melanin in the RPE, leading to toxic accumulation and subsequent atrophy of the RPE and photoreceptors, resulting in the characteristic Bull’s eye appearance. **Why other options are incorrect:** * **Infrared light:** Exposure to infrared light is associated with "Glassblower’s cataract" (thermal injury to the lens), not specific macular pigmentary changes. * **UV-light:** Chronic UV exposure is linked to photokeratitis, pterygium, and potentially age-related macular degeneration (AMD), but it does not produce a Bull’s eye lesion. * **NSAIDs:** While some NSAIDs (like Indomethacin) can rarely cause corneal deposits or retinal pigment changes, they are not the classic or primary cause of Bull’s eye retinopathy. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Cause:** The most frequently tested cause of Bull's eye maculopathy is **Chloroquine** and **Hydroxychloroquine** (used in SLE/RA). * **Differential Diagnosis (Mnemonic: "CHLORPS"):** * **C:** Chloroquine/Hydroxychloroquine * **H:** Hereditary (Stargardt disease, Cone dystrophy) * **L:** Lipofuscinosis * **O:** Other (Fenretinide) * **R:** Rod-Cone dystrophy * **P:** Phenothiazines * **S:** Spielmeyer-Vogt disease * **FA Finding:** On Fluorescein Angiography, the lesion shows a **"Window Defect"** due to RPE atrophy allowing underlying choroidal fluorescence to show through.

Question 215: Regarding Retinoblastoma, all of the following are true EXCEPT:

A. Associated with a 13q14 deletion
B. Inherited in an autosomal dominant pattern
C. Accounts for 25% of all cases (Correct Answer)
D. Represents 40% of heritable forms

Explanation: **Explanation:** Retinoblastoma is the most common primary intraocular malignancy of childhood. Understanding its genetic basis is crucial for NEET-PG. **Why Option C is the Correct Answer (The False Statement):** Retinoblastoma is a rare tumor, but it accounts for approximately **3% of all childhood cancers**, not 25%. The "25%" figure is a common distractor; however, it is important to note that it is the most common intraocular tumor in children, occurring in roughly 1 in 15,000 to 18,000 live births. **Analysis of Other Options:** * **Option A (True):** The RB1 gene is located on the long arm of **chromosome 13 (13q14)**. Deletion or mutation of this tumor suppressor gene is the primary cause of the disease. * **Option B (True):** While the mutation at the cellular level is recessive (Knudson’s Two-Hit Hypothesis), the **inheritance pattern** of the familial form is **Autosomal Dominant** with high penetrance (approx. 90%). * **Option D (True):** Approximately **40% of cases are heritable** (germline mutation), which are typically bilateral and multifocal. The remaining 60% are sporadic (somatic mutation) and usually unilateral. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presenting sign:** Leukocoria (White pupillary reflex). * **Second most common sign:** Strabismus. * **Pathology:** Flexner-Wintersteiner rosettes (highly specific) and Homer-Wright rosettes. * **Calcification:** Dystrophic calcification is a hallmark feature (seen on CT scan/Ultrasound). * **Trilateral Retinoblastoma:** Bilateral RB associated with a pinealoblastoma. * **Treatment:** Chemoreduction is currently the preferred primary treatment to "shrink" the tumor before focal therapy (cryotherapy/laser). Enucleation is reserved for advanced stages (Group E).

Question 216: What clinical finding differentiates ophthalmic artery occlusion from central retinal artery occlusion?

A. Sudden painless loss of vision
B. Box-carring of vessels
C. Area of retinal whitening
D. Absence of cherry-red spot (Correct Answer)

Explanation: ### Explanation The key to differentiating these two vascular emergencies lies in the **anatomy of the choroidal circulation**. **1. Why "Absence of cherry-red spot" is correct:** In **Central Retinal Artery Occlusion (CRAO)**, the retinal layers become edematous and opaque (white). However, the foveola is the thinnest part of the retina and lacks inner retinal layers; it receives its nutrition from the underlying **choriocapillaris**. Because the choroidal circulation remains intact in CRAO, the red color of the choroid shines through the thin foveola, creating the classic "cherry-red spot." In **Ophthalmic Artery Occlusion (OAO)**, the blockage is more proximal. Since the ophthalmic artery gives rise to both the central retinal artery and the **ciliary arteries** (which supply the choroid), both retinal and choroidal circulations are compromised. Without choroidal perfusion, the foveola remains pale/white, and the **cherry-red spot is absent**. **2. Why other options are incorrect:** * **A. Sudden painless loss of vision:** This is a hallmark feature of *both* CRAO and OAO. However, OAO typically presents with more profound vision loss (often No Light Perception) compared to CRAO. * **B. Box-carring of vessels:** This refers to the segmentation of the blood column in retinal vessels due to stasis. It is a sign of severe ischemia seen in both conditions. * **C. Area of retinal whitening:** Both conditions involve generalized retinal edema and opacification due to infarction of the inner retinal layers. **High-Yield Clinical Pearls for NEET-PG:** * **CRAO + Cilioretinal Artery:** In 15–20% of people, a cilioretinal artery (from the choroidal system) supplies the macula. In these patients, a CRAO will show a "preserved island of vision" and a patch of healthy red retina amidst the whitening. * **Amaurosis Fugax:** Often a precursor to CRAO, caused by embolic transient ischemia. * **Management:** CRAO is an emergency. Immediate measures include ocular massage, anterior chamber paracentesis, and acetazolamide to lower IOP and dislodge the embolus.

Question 217: Which of the following are risk factors for the development of diabetic retinopathy?

A. Duration of diabetes
B. Heredity
C. Pregnancy
D. All of the above (Correct Answer)

Explanation: Diabetic Retinopathy (DR) is a microangiopathic complication of diabetes mellitus. The development and progression of DR are influenced by several systemic and genetic factors. **Explanation of the Correct Answer:** * **Duration of Diabetes (Option A):** This is the **most important** risk factor. The longer a patient has diabetes, the higher the risk of developing retinopathy. Approximately 75-90% of patients with Type 1 and 60% of patients with Type 2 diabetes will show signs of DR after 20 years. * **Heredity (Option B):** Genetic predisposition plays a significant role. Specific genetic markers and family history can influence the severity and speed of retinal damage, explaining why some patients develop proliferative disease despite good glycemic control. * **Pregnancy (Option C):** Pregnancy is a known risk factor for the rapid progression of pre-existing DR. This is attributed to hormonal changes, increased retinal blood flow, and relative ischemia. Diabetic women planning pregnancy should have a baseline eye exam and frequent monitoring. Since all three factors contribute significantly to the pathogenesis, **Option D (All of the above)** is the correct choice. **High-Yield Clinical Pearls for NEET-PG:** * **Modifiable Risk Factors:** Poor glycemic control (HbA1c levels), Hypertension, Anemia, and Nephropathy (the "Renal-Retinal" relationship). * **Protective Factors:** High myopia and Carotid artery stenosis (due to reduced perfusion pressure protecting the retinal microvasculature). * **Screening:** Type 1 diabetics should be screened 5 years after diagnosis; Type 2 diabetics should be screened **at the time of diagnosis**. * **First Clinical Sign:** Microaneurysms (located in the inner nuclear layer).

Question 218: Exudative retinopathy in hypertension is due to which of the following?

A. Coarctation of the aorta
B. Type I Takayasu's arteritis
C. Renal artery stenosis (Correct Answer)
D. Diabetic atherosclerosis

Explanation: **Explanation:** The correct answer is **Renal artery stenosis**. **Underlying Medical Concept:** Exudative retinopathy (specifically **Hypertensive Retinopathy Grade IV**) is characterized by severe vascular leakage, macular edema, and the presence of a "Macular Star" (hard exudates). In the context of hypertension, this typically occurs during **Malignant or Accelerated Hypertension**. Renal artery stenosis is a classic cause of **Secondary Hypertension** mediated by the Renin-Angiotensin-Aldosterone System (RAAS). The resulting severe, refractory high blood pressure leads to a breakdown of the blood-retinal barrier, causing the leakage of plasma constituents and lipids into the retina, manifesting as exudative retinopathy. **Analysis of Incorrect Options:** * **Coarctation of the aorta:** While it causes upper limb hypertension, it rarely leads to the acute, malignant levels of diastolic pressure required to produce florid exudative retinopathy. * **Type I Takayasu's arteritis:** This primarily involves the arches of the aorta and its branches. It often leads to "pulseless disease" and **hypotensive retinopathy** (Takayasu’s Retinopathy) due to ocular ischemia, rather than hypertensive exudative changes. * **Diabetic atherosclerosis:** This contributes to chronic macrovascular disease but is not a direct mechanism for the acute exudative changes seen in hypertensive retinopathy. **High-Yield Clinical Pearls for NEET-PG:** * **Keith-Wagener-Barker Classification:** Grade IV is defined by the presence of **Papilledema**. * **Macular Star:** Formed by hard exudates (lipids) deposited in the **Henle’s layer** of the retina. * **Elschnig Spots:** Small black spots surrounded by yellow halos, representing focal choroidal infarcts (a sign of hypertensive choroidopathy). * **Siegrist Streaks:** Linear hyperpigmented streaks along choroidal vessels, also seen in malignant hypertension.

Question 219: What is true about electroretinogram?

A. The 'a' wave is a positive wave.
B. The 'a' wave arises from the pigmented epithelium.
C. The 'b' wave arises from the rods and cones.
D. The 'c' wave is a positive wave. (Correct Answer)

Explanation: ### Explanation: Electroretinogram (ERG) The Electroretinogram (ERG) is a diagnostic test that measures the electrical response of various layers of the retina to a light stimulus. **1. Why Option D is Correct:** The **'c' wave** is a slow, **positive** deflection that follows the 'b' wave. It represents the metabolic activity and electrical response of the **Retinal Pigment Epithelium (RPE)** in conjunction with the photoreceptors. **2. Analysis of Incorrect Options:** * **Option A:** The **'a' wave** is the first component of the ERG and is a **negative** wave (downward deflection). * **Option B:** The 'a' wave arises from the **photoreceptors** (rods and cones), not the RPE. It reflects the initial hyperpolarization of these cells. * **Option C:** The **'b' wave** is a large positive wave that arises from the **inner retinal layers**, specifically the **Müller cells and Bipolar cells**. It does not arise directly from the rods and cones. **3. High-Yield Clinical Pearls for NEET-PG:** * **Components Summary:** * **'a' wave:** Negative; Photoreceptors. * **'b' wave:** Positive; Bipolar/Müller cells (Largest component). * **'c' wave:** Positive; Retinal Pigment Epithelium (RPE). * **'d' wave:** Reflects the "off-response" of the retina. * **Clinical Utility:** ERG is most useful in diagnosing **Retinitis Pigmentosa** (where the ERG is typically "extinguished" or subnormal even before visual field loss occurs). * **Negative ERG:** A condition where the 'a' wave is preserved but the 'b' wave is lost (seen in Central Retinal Artery Occlusion and Congenital Stationary Night Blindness). * **EOG (Electro-oculogram):** Specifically tests RPE function (Arden Index < 1.5 is abnormal); it is the gold standard for **Best’s Disease**.

Question 220: At what distance is direct ophthalmoscopy performed?

A. 100 cm
B. 25 cm (Correct Answer)
C. As close to the patient's face as possible
D. 1 meter

Explanation: **Explanation:** Direct ophthalmoscopy is a fundamental clinical skill in ophthalmology. The procedure is typically performed in two distinct stages, which often leads to confusion regarding the "correct" distance. 1. **The Correct Answer (25 cm):** This is the distance used for **Distant Direct Ophthalmoscopy**. At approximately 25 cm (or arm's length), the examiner evaluates the **red reflex**. This distance is critical for identifying opacities in the ocular media (cornea, aqueous, lens, or vitreous). If an opacity is present, it appears as a black shadow against the red glow. 2. **Why Option C is misleading:** While the examiner eventually moves "as close as possible" (approx. 2–3 cm) to visualize the fundus details (optic disc and retina) with high magnification (15x), the standard textbook definition for the *initial* performance and screening of media opacities is 25 cm. 3. **Why Options A and D are wrong:** 100 cm (1 meter) is the standard distance for **Retinoscopy**, not direct ophthalmoscopy. At 1 meter, the magnification and field of view for direct ophthalmoscopy would be insufficient for clinical utility. **High-Yield Clinical Pearls for NEET-PG:** * **Image Characteristics:** The image in direct ophthalmoscopy is **virtual, erect, and magnified (15x)**. * **Media Opacities:** If an opacity moves in the *same* direction as the eye, it is in front of the iris; if it moves in the *opposite* direction, it is in the lens or vitreous. * **Field of View:** It is approximately **10–12 degrees**. * **Comparison:** Unlike indirect ophthalmoscopy (which provides a 3D, inverted image), direct ophthalmoscopy provides a 2D, upright image but lacks stereopsis.

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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