Diseases of the Retina Practice Questions

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 is seen at the macula. What is the most likely diagnosis?

Ocular toxoplasmosis. **Explanation:** The clinical presentation of unilateral diminished vision, mild anterior chamber reaction (iritis), vitritis, and a focal necrotic retinal lesion is classic for **Ocular Toxoplasmosis**. **Why Ocular Toxoplasmosis is correct:** * **Pathophysiology:** Caused by the parasite *Toxoplasma gondii*, it is the most common cause of posterior uveitis worldwide. * **The "Headlight in the Fog" Appearance:** The focal necrotizing retinochoroiditis causes an intense overlying vitritis. This creates the characteristic clinical sign where the white lesion is seen through a hazy vitreous. * **Location:** While it can occur anywhere, it has a predilection for the macula, leading to significant vision loss. **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 does not cause focal necrotic lesions or significant vitritis. * **Multifocal Choroiditis (MFC):** Presents with multiple, small, punched-out chorioretinal scars and lesions. While it causes vitritis, it is usually bilateral and lacks the large, solitary focal necrotic appearance of Toxoplasmosis. * **Ocular Sarcoidosis:** Characterized by granulomatous uveitis (Mutton-fat KPs), "string of pearls" vitreous opacities, and retinal periphlebitis (candle-wax drippings), rather than a focal necrotic macular lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Sign:** "Headlight in the fog" (focal retinitis + vitritis). * **Recurrence:** New lesions often arise at the margins of old, pigmented chorioretinal scars (satellite lesions). * **Treatment:** The "Triple Therapy" includes Pyrimethamine, Sulfadiazine, and Folinic acid (to prevent bone marrow toxicity), often combined with systemic steroids. * **Congenital Triad:** Chorioretinitis, Hydrocephalus, and Intracranial calcifications.

Q: All of the following are features of synchysis scintillans except?

Spherical cholesterol crystals. **Explanation:** **Synchysis Scintillans** (also known as Cholesterolosis Bulbi) is a degenerative condition characterized by the accumulation of cholesterol crystals in the vitreous. **Why Option B is the Correct Answer (The "Except"):** The crystals in synchysis scintillans are **flat, angular, and needle-like or rhombic-shaped** plates of cholesterol, not spherical. Spherical bodies (calcium-lipid complexes) are the hallmark of **Asteroid Hyalosis**, which is the primary differential diagnosis. **Analysis of Other Options:** * **A. Fluid vitreous:** Synchysis scintillans always occurs in a **liquefied vitreous** (synchysis). This allows the crystals to settle at the bottom of the vitreous cavity due to gravity when the eye is at rest. * **C. Shower of gold rain:** This is the classic clinical description. When the patient moves their eye, the settled crystals are stirred up and shimmer like a "shower of gold," then rapidly sink back to the bottom. * **D. Secondary to trauma/inflammation:** Unlike Asteroid Hyalosis (which occurs in healthy eyes), synchysis scintillans is typically a **sequela of chronic ocular disease**, such as trauma, vitreous hemorrhage, or chronic uveitis. **High-Yield Clinical Pearls for NEET-PG:** | Feature | Synchysis Scintillans | Asteroid Hyalosis | | :--- | :--- | :--- | | **Composition** | Cholesterol crystals | Calcium-lipid complexes | | **Vitreous State** | Liquefied (Synchysis) | Solid/Normal | | **Movement** | Settle inferiorly (Gravity-dependent) | Move with vitreous, return to original position | | **Shape** | Flat, rhombic plates | **Spherical** (Snowball appearance) | | **Association** | Post-traumatic/Inflammatory | Ageing, Diabetes (weakly) |

Q: Which of the following statements about Retinoblastoma is true?

Rosettes suggest good prognosis.. **Explanation:** **Retinoblastoma (RB)** is the most common primary intraocular malignancy of childhood. The correct statement is that **Rosettes suggest a good prognosis**. 1. **Why Option C is Correct:** Histologically, RB presents with two types of rosettes: **Flexner-Wintersteiner rosettes** (highly specific, representing photoreceptor differentiation) and **Homer-Wright rosettes** (less specific). The presence of these rosettes indicates a higher degree of cellular differentiation. In oncology, well-differentiated tumors generally carry a better prognosis compared to undifferentiated (anaplastic) tumors. 2. **Why Other Options are Incorrect:** * **Option A:** Only **40%** of cases are heritable (germline mutation). The remaining 60% are sporadic/non-heritable. * **Option B:** RB is caused by a mutation or deletion in the **RB1 gene** located on chromosome **13q14**, not 11q14. It follows Knudson’s "Two-Hit" hypothesis. * **Option D:** With modern management (chemotherapy, plaque brachytherapy, and enucleation), the survival rate in developed countries like the UK is over **95%**. High mortality is only seen in resource-limited settings due to delayed presentation. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presenting sign:** Leukocoria (White pupillary reflex) > Strabismus. * **Calcification:** Pathognomonic feature seen on USG/CT scan (differentiates it from Coats' disease). * **Trilateral Retinoblastoma:** Bilateral RB associated with a pinealoblastoma. * **Risk of secondary malignancies:** Patients with the heritable form are at high risk for **Osteosarcoma** later in life. * **Flexner-Wintersteiner rosettes** surround a central lumen, whereas **Homer-Wright rosettes** surround a central fibrillar meshwork.

Q: What is the commonest eye tumor?

Retinoblastoma. **Explanation:** The correct answer is **Retinoblastoma (Option B)**. This is a high-yield fact for NEET-PG, as Retinoblastoma is the **most common primary intraocular malignancy in children** and the **most common primary intraocular tumor overall**. It arises from the neurosensory retina due to a mutation in the RB1 tumor suppressor gene on chromosome 13q14. While it is a pediatric tumor, its high incidence relative to other primary ocular malignancies makes it the correct answer in this context. **Analysis of Options:** * **A. Melanoma:** Uveal melanoma is the most common primary intraocular malignancy in **adults**, but it is less frequent globally than Retinoblastoma. Note: Metastatic tumors (secondary) are technically more common than primary tumors, but among the primary options listed, Retinoblastoma prevails. * **C. Carcinoma of eyelid:** While Basal Cell Carcinoma (BCC) is the most common malignant tumor of the **eyelid**, it is an adnexal tumor, not an "eye tumor" (intraocular) in the strict sense. * **D. Carcinoma of lacrimal sac:** These are extremely rare malignancies and are never the "most common" in any category. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presenting sign:** Leukocoria (White pupillary reflex). * **Most common secondary tumor:** Metastasis (usually from breast in women, lung in men). * **Pathognomonic Histology:** Flexner-Wintersteiner rosettes. * **Calcification:** Present in 90% of cases (visible on CT/Ultrasound), a key diagnostic feature. * **Inheritance:** 40% are hereditary (bilateral/multifocal), 60% are sporadic (unilateral).

Q: Which of the following should not be given in the prophylaxis of Dry Age-Related Macular Degeneration (ARMD)?

Vitamin A. The management of Age-Related Macular Degeneration (ARMD) is a high-yield topic for NEET-PG, specifically regarding the **AREDS (Age-Related Eye Disease Study)** protocols. ### **Explanation** The correct answer is **Vitamin A**. While Vitamin A is essential for general retinal health, it is specifically excluded from the modern prophylaxis of ARMD. This is based on the findings of the **AREDS-2 trial**. In the original AREDS-1 study, **Beta-carotene** (a precursor of Vitamin A) was used. However, it was discovered that Beta-carotene supplementation significantly increases the risk of **lung cancer in smokers and former smokers**. Consequently, in the AREDS-2 formulation, Beta-carotene was replaced by Lutein and Zeaxanthin, which are safer and equally effective. ### **Analysis of Options** * **Vitamin C & Vitamin E (Options B & C):** These are potent antioxidants included in both AREDS-1 and AREDS-2 formulations. They help neutralize free radicals that cause oxidative stress in the retinal pigment epithelium (RPE). * **Lutein (Option D):** Along with Zeaxanthin, Lutein is a carotenoid that forms the macular pigment. It was added to the AREDS-2 formula as a safer alternative to Beta-carotene to provide photoprotection and antioxidant effects without the risk of lung malignancy. ### **High-Yield Clinical Pearls for NEET-PG** * **AREDS-2 Formulation:** Includes Vitamin C (500mg), Vitamin E (400 IU), Zinc (80mg), Copper (2mg), Lutein (10mg), and Zeaxanthin (2mg). * **Zinc:** Added to the formula because it is found in high concentrations in the retina/choroid; Copper is added to prevent **Zinc-induced copper deficiency anemia**. * **Indication:** Prophylaxis is indicated for patients with **Intermediate ARMD** or **Advanced ARMD in one eye** to prevent progression. It is *not* indicated for early-stage ARMD. * **Amsler Grid:** Used for home monitoring to detect the transition from Dry to Wet ARMD (metamorphopsia).

Q: What is the most common site of obstruction in the central retinal artery?

At the lamina cribrosa. **Explanation:** The **Central Retinal Artery (CRA)** is a branch of the ophthalmic artery. It enters the optic nerve approximately 10–15 mm behind the globe and travels centrally within the nerve. **Why Option B is correct:** The **lamina cribrosa** is a sieve-like meshwork of collagen and elastic fibers in the sclera through which the optic nerve fibers and the CRA pass. This is the **narrowest point** of the artery’s lumen. Due to this anatomical constriction, it is the most common site for an embolus (usually derived from the carotid arteries or heart) to become lodged, leading to **Central Retinal Artery Occlusion (CRAO)**. **Analysis of Incorrect Options:** * **Option A (In front of the lamina cribrosa):** Once the artery passes the lamina, it enters the eye and divides into superior and inferior branches. While branch retinal artery occlusions (BRAO) occur here, the primary trunk obstruction typically occurs at the point of maximum constriction (the lamina). * **Option C (Behind the lamina cribrosa):** While the artery is within the optic nerve, the lumen is relatively wider compared to the exit point at the lamina. * **Option D (Point of entry into the optic nerve):** This is a common site for inflammatory or compressive pathologies, but not the most common site for embolic obstruction. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** Sudden, painless, profound loss of vision. * **Fundus Findings:** "Cherry-red spot" at the fovea (due to the choroidal vasculature showing through the thin fovea) and "cattle-trucking" (segmentation) of blood in the retinal veins. * **Cilioretinal Artery:** Present in ~15-20% of the population; if present, it may spare central vision in CRAO as it is derived from the posterior ciliary circulation. * **Management:** Ocular emergency! Digital massage, paracentesis, and acetazolamide are used to lower IOP and dislodge the embolus.

Q: Chorioretinitis is commonly caused by all of the following except?

Onchocerciasis. **Explanation:** The correct answer is **Onchocerciasis (B)**. In ophthalmology, **Chorioretinitis** refers to inflammation of the choroid and retina, typically caused by hematogenous spread of infections. While **Onchocerciasis** (River Blindness) is a major cause of blindness, it primarily causes **Sclerosing Keratitis** (anterior segment) and **Chorioretinal Degeneration/Atrophy** (posterior segment) rather than active chorioretinitis. The ocular damage in Onchocerciasis is due to a chronic inflammatory response to microfilariae, leading to "punched-out" lesions and optic atrophy, but it is not classified as a classic cause of infectious chorioretinitis. **Analysis of Incorrect Options:** * **Toxoplasmosis (D):** This is the **most common cause** of posterior uveitis/chorioretinitis worldwide. It typically presents as a "headlight in the fog" appearance (active white lesion next to an old pigmented scar). * **Cytomegalovirus (C):** CMV retinitis is the most common opportunistic ocular infection in AIDS patients (CD4 <50). It presents with a characteristic "pizza-pie" or "cheese and ketchup" fundus appearance. * **Cryptococcosis (A):** Fungal infections like Cryptococcus often cause multifocal chorioretinitis, especially in immunocompromised individuals, spreading via the CSF or bloodstream. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Chorioretinitis:** Toxoplasmosis. * **Candida Albicans:** Causes "string of pearls" vitreous opacities. * **Onchocerciasis:** Caused by *Onchocerca volvulus* (Vector: Blackfly/Simulium). It is the second leading infectious cause of blindness worldwide. * **Syphilis:** Known as the "Great Mimicker," it can cause any form of uveitis, including salt-and-pepper fundus.

Question 1

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 is 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 2

All of the following are features of synchysis scintillans except?

Accepted Answer

Spherical cholesterol crystals

Answer

Fluid vitreous

Answer

Shower of gold rain

Answer

Secondary to trauma or inflammation of the eye

Question 3

Which of the following statements about Retinoblastoma is true?

Accepted Answer

Rosettes suggest good prognosis.

Answer

It is inherited in 50% of cases.

Answer

It is caused by deletion of 11q14.

Answer

It causes death in 60% of sufferers in the UK.

Question 4

What is the commonest eye tumor?

Accepted Answer

Retinoblastoma

Answer

Melanoma

Answer

Carcinoma of eyelid

Answer

Carcinoma of lacrimal sac

Question 5

Which of the following should not be given in the prophylaxis of Dry Age-Related Macular Degeneration (ARMD)?

Accepted Answer

Vitamin A

Answer

Vitamin C

Answer

Vitamin E

Answer

Lutein

Question 6

What is the most common site of obstruction in the central retinal artery?

Accepted Answer

At the lamina cribrosa

Answer

In front of the lamina cribrosa

Answer

Behind the lamina cribrosa

Answer

The point where the artery enters the optic nerve

Question 7

Calcification is seen in all of the following conditions except?

Accepted Answer

Persistent hyperplastic primary vitreous

Answer

Retinoblastoma

Answer

Choroidal osteoma

Answer

Optic nerve head drusen

Question 8

Chorioretinitis is commonly caused by all of the following except?

Accepted Answer

Onchocerciasis

Answer

Cryptococcosis

Answer

Cytomegalovirus infection

Answer

Toxoplasmosis

Question 9

A 5-year-old boy presents with leucocoria in the right eye, diagnosed as diffuse retinoblastoma involving the entire globe. Examination of the left eye reveals a small 2-3 mm tumor in the periphery. What is the ideal management for this patient?

Accepted Answer

Enucleation of the right eye and focal therapy for the left eye

Answer

Enucleation of both eyes

Answer

Enucleation of the right eye and observation for the left eye

Answer

Six cycles of chemotherapy

Question 10

What is the ideal treatment for bilateral retinoblastoma?

Accepted Answer

Radiation

Answer

Enucleation

Answer

Chemotherapy

Answer

Cyclophotocoagulation

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

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