Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 281: A cherry red spot at the macula is seen in all of the following conditions except?

A. Tay-Sach's disease
B. Letterer-Siwe disease (Correct Answer)
C. Niemann-Pick disease
D. Commotio retinae

Explanation: ### Explanation The **"Cherry Red Spot"** is a classic ophthalmological finding where the fovea appears bright red against a pale, opaque, or edematous surrounding retina. This occurs because the fovea is the thinnest part of the retina and lacks the ganglion cell layer; while the surrounding retina becomes cloudy (due to storage material or edema), the underlying vascular choroid remains visible through the fovea. **Why Letterer-Siwe Disease is the Correct Answer:** Letterer-Siwe disease is a multisystem form of **Langerhans Cell Histiocytosis (LCH)**. It typically presents with skin rashes, hepatosplenomegaly, and bone lesions. It does **not** involve the accumulation of metabolic storage material in the retinal ganglion cells, nor does it cause acute retinal ischemia or edema. Therefore, it does not produce a cherry red spot. **Analysis of Other Options:** * **Tay-Sachs Disease:** A sphingolipidosis (GM2 gangliosidosis) where gangliosides accumulate in the retinal ganglion cells, causing the surrounding retina to appear white, accentuating the red fovea. * **Niemann-Pick Disease:** A lysosomal storage disorder (Sphingomyelinase deficiency) that similarly leads to lipid accumulation in the ganglion cell layer, resulting in a cherry red spot (seen in 50% of Type A cases). * **Commotio Retinae (Berlin’s Edema):** Following blunt trauma, extracellular edema and disruption of the outer retinal layers occur. The opaque, edematous retina surrounds the normal fovea, creating a "pseudo" cherry red spot. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Cherry Red Spot:** *"**S**ome **M**en **A**re **C**onfused **T**onight"* (**S**andhoff’s, **M**achado-Joseph/Metachromatic Leukodystrophy, **A**maurotic idiocy/CRAO, **C**herubism/Commotio Retinae, **T**ay-Sachs). * **Most common cause:** Central Retinal Artery Occlusion (CRAO). * **Metabolic causes:** Tay-Sachs is the most common lysosomal storage cause. * **Gaucher’s Disease:** Usually **does not** have a cherry red spot (important "except" question).

Question 282: What is the characteristic appearance of the fundus in retinitis pigmentosa?

A. White spots with a red disc
B. Jet-black spots with a pale-waxy disc (Correct Answer)
C. No pigmentation
D. Dilatation of arterioles

Explanation: **Explanation:** Retinitis Pigmentosa (RP) is a hereditary dystrophy primarily affecting the rod photoreceptors and the retinal pigment epithelium (RPE). The characteristic fundus appearance is defined by a classic **clinical triad**: 1. **Bony Spicule Pigmentation:** These are "jet-black" spots caused by the migration of pigment from the RPE into the sensory retina. They typically cluster around the mid-peripheral retinal vessels. 2. **Arteriolar Attenuation:** The retinal blood vessels become markedly thin and thread-like. 3. **Waxy Pallor of the Disc:** This is due to consecutive optic atrophy resulting from the degeneration of retinal ganglion cells and glial proliferation. **Analysis of Options:** * **Option A (White spots with a red disc):** This is not seen in RP. White spots are more characteristic of conditions like *Retinitis Punctata Albescens* or *Fundus Albipunctatus*. * **Option C (No pigmentation):** While a variant called *RP sine pigmento* exists where pigmentation is absent, it is not the "characteristic" textbook appearance. * **Option D (Dilatation of arterioles):** Incorrect; RP is characterized by severe **narrowing** (attenuation) of arterioles, not dilatation. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Symptom:** Nyctalopia (Night blindness) due to rod dysfunction. * **Visual Field:** Characteristically shows a **Ring Scotoma**, which may progress to "Tubular Vision." * **ERG Findings:** The Electroretinogram (ERG) is **subnormal or extinguished** (flat) even in early stages. * **Inheritance:** Most common is Autosomal Recessive; most severe is X-linked Recessive. * **Associated Syndrome:** **Usher Syndrome** (RP + Sensorineural hearing loss) is a frequent exam topic.

Question 283: Angioid streaks are seen in which of the following conditions?

A. Pseudoxanthoma elasticum
B. Paget's disease
C. Old age
D. All of the above (Correct Answer)

Explanation: **Explanation:** **Angioid streaks** are irregular, jagged, radiating lines deep to the retina that resemble blood vessels. They represent **linear crack-like dehiscences (breaks) in a thickened, calcified, and brittle Bruch’s membrane.** **Why "All of the above" is correct:** The underlying pathophysiology involves any condition that causes mineralization or structural weakness of the elastic lamina of Bruch’s membrane. * **Pseudoxanthoma elasticum (PXE):** This is the most common systemic association (Grönblad-Strandberg syndrome). It involves a mutation in the ABCC6 gene leading to fragmentation of elastic fibers. * **Paget’s disease of bone:** Chronic bone remodeling leads to hypercalcemia and subsequent metastatic calcification of Bruch’s membrane, making it prone to cracks. * **Old age (Senile Elastosis):** Age-related degenerative changes and calcification of the elastic tissue in the eye can lead to the formation of these streaks, even in the absence of systemic disease. **Clinical Pearls & High-Yield Facts for NEET-PG:** To remember the systemic associations, use the mnemonic **"PEPSI"**: * **P** – **P**seudoxanthoma elasticum (Most common) * **E** – **E**hlers-Danlos syndrome * **P** – **P**aget’s disease of bone * **S** – **S**ickle cell anemia (and other hemoglobinopathies like Thalassemia) * **I** – **I**diopathic **Key Diagnostic Features:** * **Appearance:** Reddish-brown or grey streaks radiating from the peripapillary area (around the optic disc). * **Complication:** The most vision-threatening complication is **Choroidal Neovascularization (CNVM)**, which can lead to subretinal hemorrhage and scarring. * **Peau d'orange:** A speckled "orange peel" appearance of the retinal pigment epithelium is often seen temporal to the macula, frequently preceding the appearance of the streaks.

Question 284: A cherry red spot is seen in which of the following conditions?

A. Retinitis pigmentosa
B. Retinopathy of prematurity
C. Metachromatic leukodystrophy (Correct Answer)
D. Central retinal vein occlusion

Explanation: **Explanation:** The **Cherry Red Spot** is a classic ophthalmic sign where the foveola appears bright red against a pale, opalescent background. This occurs because the foveola is the thinnest part of the retina (lacking ganglion cells), allowing the underlying vascular choroid to shine through, while the surrounding macula becomes opaque due to intracellular accumulation of lipids or intracellular edema. **Why Metachromatic Leukodystrophy (MLD) is correct:** MLD is a lysosomal storage disorder caused by a deficiency of **Arylsulfatase A**. This leads to the accumulation of sulfatides in the ganglion cell layer of the retina, causing the surrounding macula to appear white/pale, thereby creating the "cherry red spot" appearance. **Analysis of Incorrect Options:** * **Retinitis Pigmentosa:** Characterized by the classic triad of **bony spicule pigmentation**, arteriolar attenuation, and waxy disc pallor. It does not involve macular opacification. * **Retinopathy of Prematurity (ROP):** Primarily a disease of peripheral retinal neovascularization in preterm infants; it leads to fibrous scarring and tractional retinal detachment, not a cherry red spot. * **Central Retinal Vein Occlusion (CRVO):** Characterized by a **"blood and thunder" fundus** with extensive flame-shaped hemorrhages, dilated tortuous veins, and disc edema. (Note: A cherry red spot is seen in Central Retinal *Artery* Occlusion, not Vein Occlusion). **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Cherry Red Spot:** *"**S**ome **M**en **C**an't **G**et **C**herry **F**lavored **N**ice **S**weets"* * **S**ialidosis * **M**etachromatic Leukodystrophy * **C**RAO (Most common cause in adults) * **G**aucher’s disease / **G**angliosidosis (GM1) * **C**Herry red spot at fovea * **F**arber’s disease * **N**iemann-Pick disease * **S**andhoff / **S**ay-Tachs disease (GM2) * **Important Distinction:** In Tay-Sachs, the cherry red spot is present, but there is **no** hepatosplenomegaly (unlike Niemann-Pick).

Question 285: What is the recommended treatment for CMV retinitis in an AIDS patient?

A. Amantadine
B. Fludrabine
C. Oseltamivir
D. Valganciclovir (Correct Answer)

Explanation: **Explanation:** **CMV Retinitis** is the most common opportunistic ocular infection in patients with AIDS, typically occurring when the CD4+ T-cell count falls below **50 cells/mm³**. It is characterized by a "pizza-pie" or "cheese and ketchup" fundus appearance due to retinal necrosis and hemorrhage. **Why Valganciclovir is correct:** The mainstay of treatment for CMV retinitis is anti-CMV agents that inhibit viral DNA polymerase. **Valganciclovir** (an oral prodrug of Ganciclovir) is the preferred treatment because it offers high oral bioavailability, achieving plasma levels comparable to intravenous Ganciclovir. It is used for both induction and maintenance therapy, significantly reducing the pill burden and the need for indwelling catheters. **Why the other options are incorrect:** * **Amantadine:** An antiviral used primarily for Influenza A and Parkinson’s disease; it has no activity against CMV. * **Fludarabine:** A purine analog chemotherapy agent used in the treatment of chronic lymphocytic leukemia (CLL), not an antiviral. * **Oseltamivir:** A neuraminidase inhibitor used specifically for the treatment and prophylaxis of Influenza A and B. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Oral Valganciclovir is the first-line treatment. For sight-threatening lesions (near the macula or optic nerve), **Intravitreal Ganciclovir or Foscarnet** may be added. * **Alternative Agents:** Foscarnet and Cidofovir (used if there is resistance or systemic toxicity). * **Side Effects:** Ganciclovir/Valganciclovir can cause **bone marrow suppression** (neutropenia), while Foscarnet is notably **nephrotoxic**. * **HAART:** Initiation of Highly Active Antiretroviral Therapy is crucial for long-term management to restore immune function.

Question 286: Which method is used to visualize the periphery of the retina?

A. Indirect binocular ophthalmoscopy (Correct Answer)
B. Direct ophthalmoscopy
C. Anterior segment lens
D. Goldman's three-mirror contact lens

Explanation: **Explanation:** The visualization of the retinal periphery is a critical component of a fundus examination, especially for detecting peripheral degenerations or retinal detachments. **1. Why Indirect Binocular Ophthalmoscopy (IBO) is Correct:** IBO is the gold standard for visualizing the **peripheral retina up to the Ora Serrata**. It offers a **wide field of view** (about 37°–60°) and, most importantly, allows for **scleral indentation**. By indenting the sclera, the peripheral retina is brought into the examiner's line of sight, enabling visualization of the extreme periphery. Additionally, it provides a stereoscopic (3D) view, which is essential for identifying retinal elevation. **2. Why the Other Options are Incorrect:** * **Direct Ophthalmoscopy:** This provides a highly magnified (15x) but very narrow field of view (about 10°). It cannot visualize the retina beyond the equator and lacks stereopsis. * **Anterior Segment Lens:** As the name suggests, these lenses (like the Hruby lens or 78D/90D lenses used with a slit lamp) are primarily used for the posterior pole and macula. While 90D lenses can see the mid-periphery, they cannot reach the extreme periphery as effectively as IBO. * **Goldmann’s Three-Mirror Contact Lens:** While this *can* visualize the periphery, the question asks for the standard "method" or primary tool. The three-mirror lens is a contact procedure used for detailed evaluation of specific lesions (like a retinal tear) rather than a general screening of the periphery. **High-Yield Clinical Pearls for NEET-PG:** * **Image in IBO:** Real, inverted, and magnified (magnification depends on the lens power; a 20D lens provides ~3x magnification). * **Lens Power vs. Field:** Higher power lenses (e.g., 30D) provide a wider field of view but lower magnification compared to 20D lenses. * **Scleral Indentation:** This is the maneuver that specifically allows visualization of the **Ora Serrata**, the most anterior part of the retina.

Question 287: What is the standard treatment regimen for retinoblastoma?

A. 5-Fluorouracil + Cisplatin + Vinblastine
B. Carboplatin + Etoposide + Vincristine (Correct Answer)
C. Cyclophosphamide + Etoposide + Vincristine
D. Cyclophosphamide + Doxorubicin + Etoposide

Explanation: **Explanation:** The standard of care for chemoreduction in Retinoblastoma is the **CEV regimen**, which consists of **Carboplatin, Etoposide, and Vincristine**. **Why Option B is Correct:** Chemoreduction is primarily used to shrink the tumor size to allow for focal consolidation therapies (like cryotherapy or laser photocoagulation) and to avoid enucleation or external beam radiotherapy (EBRT). * **Carboplatin:** An alkylating agent that is the backbone of the treatment; it has better ocular penetration and lower nephrotoxicity compared to Cisplatin. * **Etoposide:** A topoisomerase II inhibitor. * **Vincristine:** A microtubule inhibitor. This combination is highly effective in treating intraocular retinoblastoma while minimizing long-term systemic side effects. **Why Other Options are Incorrect:** * **Option A:** Cisplatin is generally avoided in pediatric ocular cases due to high risk of ototoxicity and nephrotoxicity. Vinblastine is typically used in lymphomas/histiocytosis, not retinoblastoma. * **Option C & D:** Cyclophosphamide was historically used but has been largely replaced in standard protocols due to the high risk of inducing secondary malignancies (like bladder cancer or leukemia) and its potential for causing infertility. Doxorubicin is cardiotoxic and not part of the primary intraocular management. **High-Yield Clinical Pearls for NEET-PG:** * **Most common intraocular malignancy** in children. * **RB1 Gene:** Located on Chromosome **13q14**. * **Knudson’s Two-Hit Hypothesis:** Explains the genetic basis (hereditary vs. sporadic). * **Clinical Sign:** Leukocoria (white pupillary reflex) is the most common presentation. * **Histopathology:** Look for **Flexner-Wintersteiner rosettes** (pathognomonic) and Homer-Wright rosettes. * **Calcification:** Presence of intraocular calcification on CT scan is a hallmark diagnostic feature.

Question 288: All except one are tests for macular functions?

A. Laser interferometry
B. Two-point discrimination
C. Maddox rod test
D. Retinal electroretinogram (Correct Answer)

Explanation: **Explanation:** The **Retinal Electroretinogram (ERG)** is the correct answer because it is a measure of the **generalized** electrical activity of the entire retina, primarily the photoreceptors and inner retinal layers. In cases of isolated macular disease, the standard ERG remains **normal** because the macula represents only a tiny fraction (approx. 2%) of the total retinal area. To specifically test macular function via electrophysiology, a *Multifocal ERG (mfERG)* or *Pattern ERG (pERG)* is required. **Analysis of other options (Macular Function Tests):** * **Laser Interferometry:** A subjective test used to assess **potential visual acuity** (retinal acuity) behind a cataract. It bypasses optical opacities to project interference fringes directly onto the macula. * **Two-point Discrimination:** This is the physiological basis of **visual acuity**. The macula (specifically the fovea) has the highest cone density, allowing the eye to distinguish two close points as separate entities. * **Maddox Rod Test:** While primarily used for squint (phorias/tropias), in the context of macular function, it is used to assess **macular projection**. If a patient can accurately perceive the orientation and position of the red line, it indicates functioning macular receptors. **NEET-PG High-Yield Pearls:** * **Clinical Macular Tests:** Amsler Grid (metamorphopsia), Photostress test (recovery time >50-60s indicates macular disease), and Color vision (Ishihara). * **EOG (Electro-oculogram):** Measures the standing potential between the cornea and retina; it is the gold standard for **Best Disease**. * **ERG Components:** 'a' wave (photoreceptors), 'b' wave (Müller & Bipolar cells). ERG is extinguished in **Retinitis Pigmentosa**.

Question 289: What is the area of highest visual resolution in the retina?

A. Macula lutea
B. Foveola centralis (Correct Answer)
C. Blind spot
D. None of the above

Explanation: ### Explanation **Correct Answer: B. Foveola centralis** The **foveola centralis** is the area of highest visual resolution (visual acuity) because it contains the highest density of cone photoreceptors in the entire retina. Anatomically, it is a 0.35 mm diameter depression located at the center of the fovea. To maximize resolution, all internal layers of the retina (including the ganglion cell layer and plexiform layers) are displaced laterally, allowing light to fall directly onto the cones without scattering. Furthermore, in this region, each cone synapses with a single bipolar cell and a single ganglion cell (a 1:1 ratio), ensuring minimal convergence and maximal spatial resolution. **Why other options are incorrect:** * **A. Macula lutea:** This is a larger area (approx. 5.5 mm) responsible for central vision. While it contains the fovea and foveola, the macula as a whole does not have the same peak density of cones or the specialized "one-to-one" neural circuitry found specifically in the foveola. * **C. Blind spot:** This corresponds to the **Optic Disc**, where the optic nerve exits the eye. It contains no photoreceptors (rods or cones) and therefore has zero visual resolution. **High-Yield Clinical Pearls for NEET-PG:** * **Foveola Anatomy:** It is the thinnest part of the retina and contains **only cones** (no rods). * **Blood Supply:** The foveola is avascular (Foveal Avascular Zone - FAZ) and relies on the underlying choriocapillaris for nutrition. * **Henle’s Layer:** The axons of the photoreceptors in the foveal region are oriented obliquely and are known as Henle’s fiber layer; this is where yellow exudates accumulate in a "star" pattern (e.g., in hypertensive retinopathy). * **Macular Pigments:** The yellow color of the macula is due to carotenoid pigments (**Lutein and Zeaxanthin**), which protect the retina from UV damage.

Question 290: Macular edema is caused by all of the following mechanisms EXCEPT:

A. Microaneurysms
B. Capillary dilatation
C. Neovascularization
D. None of the above (Correct Answer)

Explanation: **Explanation:** The correct answer is **None of the above** because all the listed mechanisms (microaneurysms, capillary dilatation, and neovascularization) are classic pathological causes of macular edema. **Underlying Medical Concept:** Macular edema occurs due to the breakdown of the **Blood-Retinal Barrier (BRB)**. When the tight junctions of the retinal vascular endothelium are compromised, fluid, proteins, and lipids leak into the extracellular space of the neurosensory retina, particularly within the outer plexiform and inner nuclear layers. * **Microaneurysms (Option A):** These are the earliest clinical signs of diabetic retinopathy. They are thin-walled focal outpouchings of capillaries that are highly permeable. Leakage from these microaneurysms is a primary cause of focal macular edema. * **Capillary Dilatation (Option B):** Chronic hypoxia leads to the release of vasoproliferative factors (like VEGF), causing telangiectatic changes and dilatation of existing capillaries. These dilated vessels are "leaky," contributing to diffuse macular edema. * **Neovascularization (Option C):** New vessels formed in response to ischemia (as seen in Proliferative Diabetic Retinopathy or Wet AMD) lack a mature endothelial structure and tight junctions. They are inherently fragile and prone to significant leakage and exudation. **Clinical Pearls for NEET-PG:** * **Cystoid Macular Edema (CME):** Characterized by a "Flower-petal" appearance on Fundus Fluorescein Angiography (FFA) due to fluid accumulation in Henle’s layer (outer plexiform layer). * **Irvine-Gass Syndrome:** A specific type of CME occurring after cataract surgery. * **Gold Standard Investigation:** Optical Coherence Tomography (OCT) is the most sensitive tool to quantify macular thickness, while FFA is used to identify the source of leakage. * **Drug-induced CME:** Can be caused by Latanoprost, Epinephrine, and Nicotinic acid.

Practice by Chapter

Retinal Anatomy and Physiology

Practice Questions

Age-Related Macular Degeneration

Practice Questions

Diabetic Retinopathy

Practice Questions

Retinal Vascular Diseases

Practice Questions

Retinal Detachment

Practice Questions

Hereditary Retinal Dystrophies

Practice Questions

Inflammatory Retinal Diseases

Practice Questions

Retinal Tumors

Practice Questions

Retinopathy of Prematurity

Practice Questions

Retinal Imaging Techniques

Practice Questions

Intravitreal Pharmacotherapy

Practice Questions

Vitreoretinal Surgery

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free