Diseases of the Retina Practice Questions

Q: What causes a cherry red spot?

Berlin's edema. **Explanation:** A **Cherry Red Spot** is a clinical sign where the fovea appears bright red against a pale, edematous background. This occurs because the foveola is the thinnest part of the retina, lacking the ganglion cell layer. When the surrounding retina becomes opaque due to edema or storage material, the underlying vascular choroid shines through the foveola, creating the "red spot" appearance. **Why Berlin’s Edema is correct:** Berlin’s Edema (Commotio Retinae) occurs following blunt trauma to the eye. The trauma causes extracellular edema and disruption of the outer retinal layers (photoreceptors and RPE). This opacification of the surrounding retina makes the normal choroidal vasculature at the fovea stand out as a cherry red spot. **Why the other options are incorrect:** * **Central Retinal Vein Occlusion (CRVO):** This is characterized by a "Blood and Thunder" appearance (extensive flame-shaped hemorrhages, dilated tortuous veins, and disc edema). It does **not** cause a cherry red spot. * **Eales Disease:** This is an idiopathic peripheral perivasculitis (inflammation of vessel walls) leading to peripheral non-perfusion and vitreous hemorrhage. It does not typically involve the macula in a way that produces a cherry red spot. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Central Retinal Artery Occlusion (CRAO). * **Metabolic causes:** Tay-Sachs disease (most common lysosomal storage disorder), Niemann-Pick disease, and Gaucher’s disease. * **Traumatic cause:** Berlin’s Edema. * **Drug-induced:** Quinine toxicity. * **Mnemonic (OCHRE):** **O**clusion (CRAO), **C**herry red spot (Tay-Sachs), **H**urler’s, **R**etinal trauma (Berlin's), **E**dema.

Q: Retinal tear is associated with which degeneration?

Lattice retinal degeneration. **Explanation:** **Lattice Retinal Degeneration** is the most common peripheral retinal degeneration associated with **rhegmatogenous retinal detachment (RRD)**. It is characterized by thinning of the inner retinal layers and overlying vitreous liquefaction (synchysis), but most importantly, there is **strong vitreoretinal adhesion** at the margins of the lattice lesion. When the vitreous collapses (Posterior Vitreous Detachment), the traction at these adherent margins leads to **U-shaped (horseshoe) tears**, which allow fluid to enter the subretinal space, causing detachment. Approximately 30% of patients with RRD have underlying lattice degeneration. **Analysis of Incorrect Options:** * **Equatorial Drusen:** These are small, yellow-white deposits (extracellular material) located under the sensory retina. They are common age-related changes and do not predispose to retinal tears or detachment. * **Reticular Pigmentary Degeneration:** Also known as "senile pigmentary degeneration," it is a benign age-related change characterized by a honeycomb pattern of hyperpigmentation. It is not associated with an increased risk of retinal breaks. * **Paving Stone (Cobblestone) Degeneration:** This involves discrete areas of chorioretinal atrophy. While it looks significant on fundoscopy, the retina is actually firmly adherent to the underlying choroid in these areas, making it a "protective" factor against the spread of detachment; it does not cause tears. **High-Yield Clinical Pearls for NEET-PG:** * **Snail Track Degeneration:** Considered a variant of lattice; it also carries a risk of retinal holes. * **Most common site for Lattice:** Temporal quadrant (superior-temporal most frequent). * **Prophylaxis:** Laser photocoagulation or cryotherapy is indicated if lattice is associated with symptoms (flashes/floaters) or in the fellow eye of a patient who already had a retinal detachment.

Q: What condition presents with a 'cattle truck' appearance on fundus examination?

Incomplete Central Retinal Artery Occlusion (CRAO). ### Explanation The correct answer is **Incomplete Central Retinal Artery Occlusion (CRAO)**. **1. Why it is correct:** The "cattle truck" appearance (also known as **segmentation** or **box-carring**) of the retinal blood column is a classic sign of severely slowed blood flow. In CRAO, the arterial supply is obstructed, leading to the fragmentation of the blood column into segments of red cells separated by clear plasma. This phenomenon is most visible in the veins and arteries during an *incomplete* or *evolving* occlusion, where the flow is sluggish but not entirely absent. **2. Why the other options are incorrect:** * **Central Retinal Vein Occlusion (CRVO):** This presents with a "Blood and Thunder" fundus, characterized by massive retinal hemorrhages, dilated tortuous veins, and disc edema. * **Incomplete CRVO:** While flow is slowed, the primary clinical feature is venous engorgement and scattered hemorrhages, not the distinct segmentation of the blood column seen in arterial compromise. * **Hypertensive Retinopathy:** This is characterized by arteriolar narrowing, AV nipping, flame-shaped hemorrhages, and Cotton Wool spots (Grade III) or papilledema (Grade IV), but not segmentation of the blood flow. **3. NEET-PG High-Yield Clinical Pearls:** * **CRAO Classic Triad:** Sudden painless loss of vision, Cherry Red Spot (at the fovea), and Cattle-trucking/Box-carring. * **Cherry Red Spot:** Occurs because the thin fovea allows the underlying vascular choroid to show through, while the surrounding macula is pale due to retinal edema. * **Amaurosis Fugax:** A common precursor to CRAO, often described as a "curtain falling" over the eye. * **Management:** CRAO is an ophthalmic emergency. Immediate measures include digital ocular massage and paracentesis to lower Intraocular Pressure (IOP) in an attempt to dislodge the embolus.

Q: All of the following are causes of exudative retinal detachment, EXCEPT:

Retinopathy of prematurity. **Explanation:** The core concept in this question is distinguishing between the three types of retinal detachment (RD): **Rhegmatogenous** (due to a break/hole), **Tractional** (due to pulling by membranes), and **Exudative** (due to fluid accumulation under the retina without a break). **Why Retinopathy of Prematurity (ROP) is the correct answer:** ROP is a vasoproliferative disorder where abnormal fibrovascular membranes grow into the vitreous. These membranes contract, pulling the neurosensory retina away from the retinal pigment epithelium (RPE). Therefore, ROP causes a **Tractional Retinal Detachment**, not an exudative one. **Analysis of Incorrect Options (Causes of Exudative RD):** Exudative RD occurs when fluid leaks from the choroidal vessels or RPE due to inflammation, tumors, or vascular anomalies. * **Sympathetic Ophthalmitis:** A bilateral granulomatous panuveitis following trauma. The intense choroidal inflammation leads to fluid leakage (exudation) under the retina. * **Posterior Scleritis:** Inflammation of the posterior sclera causes thickening and secondary subretinal fluid accumulation. * **Orbital Cellulitis:** Severe orbital inflammation can spread to the posterior segment of the eye, leading to reactive choroidal effusion and exudative RD. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of RD:** Rhegmatogenous (associated with Myopia and Lattice degeneration). * **Shifting Fluid Sign:** Pathognomonic for Exudative RD (fluid moves with gravity). * **Tobacco Dust (Shafer’s Sign):** Pigment cells in the vitreous, highly suggestive of a retinal tear (Rhegmatogenous RD). * **Concave vs. Convex:** Tractional RD typically has a **concave** configuration and is non-mobile, whereas Rhegmatogenous/Exudative RDs are usually **convex**.

Q: Retinoblastoma spreads to the CNS through which route?

Direct extension. **Explanation:** Retinoblastoma is the most common intraocular malignancy of childhood. Understanding its routes of metastasis is crucial for NEET-PG. **Why "Direct Extension" is correct:** The most common route for Retinoblastoma to involve the Central Nervous System (CNS) is via **direct extension through the optic nerve**. The tumor cells invade the lamina cribrosa, travel along the optic nerve, and reach the subarachnoid space at the level of the optic chiasm. From there, they spread into the cerebrospinal fluid (CSF) and the brain. Direct extension can also occur through the sclera into the orbit. **Analysis of Incorrect Options:** * **Lymphatic spread:** The eye lacks a traditional lymphatic drainage system. Lymphatic spread only occurs if the tumor involves the conjunctiva or eyelids, draining to preauricular or submandibular nodes. It is not the route to the CNS. * **Arterial embolization:** While Retinoblastoma spreads hematogenously (most commonly to bone marrow, liver, and lungs), this occurs via **venous** channels, not arterial embolization. * **Vitreous seeding:** This refers to the internal shedding of tumor cells into the vitreous cavity. While this is a hallmark of endophytic growth and complicates local treatment, it is an intraocular event and not a mechanism for CNS metastasis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of distant metastasis:** Bone marrow. * **Flexner-Wintersteiner Rosettes:** Pathognomonic histological feature (indicates photoreceptor differentiation). * **Homer-Wright Rosettes:** Seen in Retinoblastoma but also in Neuroblastoma and Medulloblastoma (less specific). * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pineal gland tumor (Pineoblastoma). * **Calcification:** A key radiological sign on CT scans, helping differentiate it from Coats' disease.

Q: Increased LDH in aqueous humor suggests which diagnosis?

Retinoblastoma. **Explanation:** **Retinoblastoma** is the correct answer because it is a highly malignant intraocular tumor characterized by rapid cell turnover and anaerobic metabolism. In these cases, the enzyme **Lactate Dehydrogenase (LDH)** is released into the aqueous humor. * **The Diagnostic Ratio:** A high-yield point for exams is the **Aqueous-to-Serum LDH ratio**. In a normal eye, this ratio is less than 1.0. In Retinoblastoma, the ratio typically exceeds **1.5**, making it a useful biochemical marker for diagnosis, especially in atypical presentations. **Analysis of Incorrect Options:** * **Galactosemia:** This is a metabolic disorder leading to "oil droplet" cataracts due to the accumulation of dulcitol in the lens. It does not typically elevate aqueous LDH. * **Glaucoma:** While glaucoma involves increased intraocular pressure and potential optic nerve damage, it is not a neoplastic process and does not show a significant rise in aqueous LDH. * **Gyrate Atrophy:** This is an autosomal recessive chorioretinal degeneration caused by a deficiency of the enzyme **ornithine aminotransferase**. It is characterized by high levels of **ornithine** in the blood and urine, not LDH in the aqueous. **High-Yield Clinical Pearls for NEET-PG:** * **Most common intraocular tumor of childhood:** Retinoblastoma. * **Most common presenting sign:** Leukocoria (White pupillary reflex). * **Pathognomonic Histology:** Flexner-Wintersteiner rosettes. * **Calcification:** Present in 90% of cases (visible on CT scan), a key feature distinguishing it from Coats' disease. * **Other markers:** High levels of **neuron-specific enolase (NSE)** may also be found in the aqueous humor of Retinoblastoma patients.

Question 1

A 45-year-old male presents with proliferative diabetic retinopathy and significant vitreomacular traction. What is the most appropriate treatment?

Accepted Answer

Vitrectomy with endophotocoagulation

Answer

Pan retinal photocoagulation

Answer

Intravitreal Ozurdex (dexamethasone implant)

Answer

Intravitreal anti-VEGF injection

Question 2

What causes a cherry red spot?

Accepted Answer

Berlin's edema

Answer

Central Retinal Vein Occlusion (CRVO)

Answer

Eales disease

Answer

All of the above

Question 3

Retinal tear is associated with which degeneration?

Accepted Answer

Lattice retinal degeneration

Answer

Equatorial drusen

Answer

Reticular pigmentary degeneration

Answer

Paving stone degeneration

Question 4

All of the following are true about Retinitis punctata albescens except?

Accepted Answer

Particularly involves posterior pole of retina

Answer

Autosomal dominant

Answer

Retinal pigment deposition in epithelium

Answer

White dots on fundus examination

Question 5

What condition presents with a 'cattle truck' appearance on fundus examination?

Accepted Answer

Incomplete Central Retinal Artery Occlusion (CRAO)

Answer

Central Retinal Vein Occlusion (CRVO)

Answer

Incomplete Central Retinal Vein Occlusion (CRVO)

Answer

Hypertensive Retinopathy

Question 6

All of the following are causes of exudative retinal detachment, EXCEPT:

Accepted Answer

Retinopathy of prematurity

Answer

Sympathetic ophthalmitis

Answer

Posterior scleritis

Answer

Orbital cellulitis

Question 7

Which of the following is useful in the management of choroiditis?

Accepted Answer

Steroids

Answer

Antibiotics

Answer

Miotics

Answer

Padding

Question 8

Retinoblastoma spreads to the CNS through which route?

Accepted Answer

Direct extension

Answer

Lymphatic spread

Answer

Arterial embolization

Answer

Vitreous seeding

Question 9

Increased LDH in aqueous humor suggests which diagnosis?

Accepted Answer

Retinoblastoma

Answer

Galactosemia

Answer

Glaucoma

Answer

Gyrate atrophy

Question 10

Which of the following is true regarding intraocular retinoblastoma?

Accepted Answer

Intraocular Retinoblastoma Classification (ICRB) is presently being followed to decide the treatment modality.

Answer

60% are familial and the rest about 40% occur sporadically.

Answer

Leukocoria or yellowish-white pupillary reflex is the second commonest presenting feature.

Answer

All of the above

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

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