Diseases of the Retina Practice Questions

Q: All are macular function tests except?

Scanning laser polarimetry. **Explanation:** The macula is responsible for central vision, high-resolution visual acuity, and color perception. Macular function tests are clinical investigations used to assess the functional integrity of the macula, especially when the media (cornea or lens) is opaque. **Why Scanning Laser Polarimetry (SLP) is the correct answer:** Scanning Laser Polarimetry (e.g., GDx) is not a functional test but a **structural imaging modality**. It uses polarized light to measure the thickness of the **Retinal Nerve Fiber Layer (RNFL)** based on the principle of birefringence. It is primarily used for the early diagnosis and monitoring of **Glaucoma**, not for assessing macular function. **Analysis of Incorrect Options:** * **Visual Acuity:** This is the most basic test of macular function, assessing the fovea's ability to resolve fine detail. * **Colour Vision:** The cones are densely packed in the fovea centralis. Testing color vision (e.g., Ishihara charts) is a sensitive indicator of macular health. * **Entoptic Phenomenon:** These are visual perceptions caused by the eye's own internal structures. Examples include **Blue Field Entoptoscopy** (to visualize macular capillary circulation) and the **Maxwell spot**, both used to assess macular viability behind cataracts. **Clinical Pearls for NEET-PG:** * **Other Macular Function Tests:** Amsler Grid (detects metamorphopsia), Photostress test (recovery time >50-60s is abnormal), Contrast sensitivity, and Potential Acuity Meter (PAM). * **Electrophysiology:** The **mfERG (Multifocal Electroretinogram)** is the specific electrophysiological test for macular function, whereas the standard ERG reflects global retinal activity. * **Watzke-Allen Test:** A clinical test using a slit lamp beam to confirm a Full-Thickness Macular Hole (FTMH).

Q: Which condition is associated with HLA-A29?

Birdshot retinochoroidopathy. **Explanation:** **Birdshot Retinochoroidopathy (BSRC)** is the correct answer because it has the strongest known association between a disease and an HLA haplotype in all of medicine. Approximately **95–97% of patients** with BSRC are positive for **HLA-A29**. It is a chronic, bilateral posterior uveitis characterized by multiple cream-colored, oval spots (resembling birdshot from a shotgun) scattered throughout the fundus, primarily in the post-equatorial region. **Analysis of Incorrect Options:** * **A. Serpiginous geographical choroidopathy:** This is a chronic, progressive inflammatory disease of the choriocapillaris and RPE. While it has some associations with HLA-B7, it is not linked to HLA-A29. * **C. Sympathetic ophthalmitis:** This is a bilateral granulomatous panuveitis following penetrating trauma or surgery to one eye. It is most commonly associated with **HLA-DR4** and HLA-DQw3, not HLA-A29. * **D. Acute posterior multifocal placoid pigment epitheliopathy (APMPPE):** This is a self-limiting condition characterized by multiple cream-colored placoid lesions. It is associated with **HLA-B7 and HLA-DR2**, often following a viral prodrome. **NEET-PG High-Yield Pearls:** * **The "A29" Rule:** If you see HLA-A29 in a question, the answer is almost always Birdshot Retinochoroidopathy. * **Clinical Presentation:** Patients typically present with floaters and blurred vision; the hallmark is the "birdshot" pattern of lesions that spare the macula initially. * **Investigation:** Indocyanine Green (ICG) angiography is superior to Fluorescein Angiography (FA) for visualizing the deep choroidal lesions. * **Treatment:** Requires long-term systemic immunosuppression (e.g., Cyclosporine) to prevent vision loss from cystoid macular edema (CME).

Q: Which of the following statements regarding Retinopathy of Prematurity is true?

Most cases resolve spontaneously.. **Explanation:** **Retinopathy of Prematurity (ROP)** is a vasoproliferative disorder affecting the immature retina of preterm infants. 1. **Why Option B is Correct:** The majority of infants with ROP (approximately 80–90%) develop only mild stages (Stage 1 or 2) that undergo **spontaneous regression** without requiring any medical or surgical intervention. Only a small percentage progress to "Threshold Disease" or retinal detachment requiring treatment. 2. **Why Other Options are Incorrect:** * **Option A:** ROP is classified into **5 stages** based on severity (Stage 1: Demarcation line to Stage 5: Total retinal detachment), not 4. * **Option C:** Based on anatomical location, **Zone 1** is centered on the disc, **Zone 2** extends to the nasal ora serrata, and **Zone 3** is the remaining **temporal crescent** of the retina. Zone 3 does *not* include the nasal retina. * **Option D:** The primary risk factors are **low birth weight (<1500g)**, **low gestational age (<32 weeks)**, and **unmonitored oxygen therapy**. Polyhydramnios is not a recognized risk factor for ROP. **High-Yield Clinical Pearls for NEET-PG:** * **Plus Disease:** Characterized by venous dilation and arterial tortuosity in the posterior pole; it indicates active, aggressive disease. * **Screening Timing:** The first screening should be done at **4 weeks post-natal age** or **31 weeks post-conceptional age** (whichever is later). * **Treatment of Choice:** Laser photocoagulation (diode laser) of the peripheral avascular retina is the gold standard. Anti-VEGF agents (e.g., Ranibizumab) are increasingly used for Zone 1 disease.

Q: What is the most common cause of gradual vision loss in Diabetic Retinopathy?

Macular edema. **Explanation:** In Diabetic Retinopathy (DR), visual impairment occurs through two primary mechanisms: **gradual** loss and **sudden** loss. **1. Why Macular Edema is Correct:** Diabetic Macular Edema (DME) is the **most common cause of gradual, painless vision loss** in patients with both Non-Proliferative (NPDR) and Proliferative Diabetic Retinopathy (PDR). Chronic hyperglycemia leads to a breakdown of the blood-retinal barrier, causing fluid leakage and lipid exudation (Hard Exudates) into the macula. This thickening of the central retina distorts the foveal architecture, leading to a progressive decline in visual acuity. **2. Analysis of Incorrect Options:** * **Cataract (A):** While diabetics are prone to developing cataracts earlier (snowflake cataracts), it is a secondary complication and not the primary retinal cause of vision loss in DR. * **Glaucoma (C):** Neovascular Glaucoma (NVG) can occur in advanced PDR due to rubeosis iridis, but this typically presents with pain and acute vision loss rather than the classic gradual decline seen with DME. * **Keratoconus (D):** This is a corneal ectasia unrelated to the pathophysiology of Diabetic Retinopathy. **3. NEET-PG High-Yield Pearls:** * **Most common cause of sudden vision loss in DR:** Vitreous Hemorrhage. * **First clinical sign of DR:** Microaneurysms (seen in the Inner Nuclear Layer). * **Earliest pathological change:** Loss of Pericytes and basement membrane thickening. * **Investigation of choice for DME:** Optical Coherence Tomography (OCT) is used to quantify macular thickness; Fundus Fluorescein Angiography (FFA) identifies the source of leakage. * **Treatment Gold Standard for DME:** Intravitreal Anti-VEGF injections (e.g., Ranibizumab, Bevacizumab).

Q: Examination of the fundus shows a cherry-red spot in all of the following conditions, EXCEPT:

Central retinal vein occlusion. **Explanation:** The **cherry-red spot** is a clinical sign where the fovea appears bright red against a pale, edematous background. This occurs because the fovea is the thinnest part of the retina, lacking the ganglion cell layer. When the surrounding retina becomes opaque (due to ischemia or metabolic storage), the underlying vascular choroid shines through at the fovea, creating the "red spot" appearance. **Why Central Retinal Vein Occlusion (CRVO) is the correct answer:** In CRVO, there is a backup of blood due to venous obstruction, leading to widespread retinal hemorrhages, tortuous veins, and disc edema (the **"Blood and Thunder"** fundus). It does **not** cause a cherry-red spot. A cherry-red spot is characteristic of Central Retinal *Artery* Occlusion (CRAO), where sudden ischemia causes retinal whitening. **Analysis of incorrect options:** * **Tay-Sachs & Niemann-Pick Disease:** These are Lysosomal Storage Disorders (Sphingolipidoses). Accumulation of lipids (Gangliosides and Sphingomyelin, respectively) in the retinal ganglion cells causes the surrounding retina to appear white, highlighting the red fovea. * **Gaucher’s Disease:** While rare, a cherry-red spot can be seen in the perinatal/infantile forms of Gaucher’s due to glucosylceramide accumulation. **NEET-PG High-Yield Pearls:** * **Mnemonic for Cherry-Red Spot:** "**S**andhoff's, **T**ay-Sachs, **R**etinal Artery Occlusion, **I**nfantile Gaucher's, **N**iemann-Pick, **G**angliosidosis (GM1)." (**STRING**) * **CRAO:** The most common cause of a cherry-red spot in adults. * **Tay-Sachs:** The most common cause in children. * **Quinine Poisoning:** An important toxicological cause of a cherry-red spot.

Q: Which of the following is NOT seen in Central Retinal Artery (CRA) occlusion?

Gradual loss of vision. **Explanation:** **Central Retinal Artery Occlusion (CRAO)** is a true ophthalmic emergency, often referred to as an "ocular stroke." **Why "Gradual loss of vision" is the correct answer:** CRAO is characterized by an **abrupt, painless, and profound loss of vision** (typically counting fingers to light perception). Because the central retinal artery is an end-artery, its occlusion leads to immediate ischemic necrosis of the inner retinal layers. **Gradual** vision loss is characteristic of conditions like cataracts, open-angle glaucoma, or age-related macular degeneration, not acute vascular occlusions. **Analysis of Incorrect Options:** * **Sudden loss of vision:** This is the hallmark clinical presentation of CRAO. * **Headache:** While not a primary symptom of the occlusion itself, CRAO is frequently associated with **Giant Cell Arteritis (GCA)** in elderly patients. In such cases, patients often present with a new-onset headache, jaw claudication, and scalp tenderness. * **Retained central vision:** This occurs in approximately 15–25% of the population who possess a **Cilioretinal artery** (a branch of the posterior ciliary artery). If this artery is present, the macular area remains perfused despite CRAO, sparing central visual acuity. **High-Yield Clinical Pearls for NEET-PG:** * **Fundus Findings:** "Cherry-red spot" at the fovea (due to the thin fovea showing the underlying choroid) and "cattle-track" appearance of retinal vessels. * **Ground Glass Appearance:** The retina appears milky-white due to intracellular edema. * **Management:** Immediate ocular massage, anterior chamber paracentesis, and inhalation of Carbogen (95% $O_2$, 5% $CO_2$) to induce vasodilation. * **Most common cause:** Embolism (usually from the carotid artery or heart).

Q: Which of the following statements regarding familial retinoblastoma are correct?

More commonly bilateral. **Explanation:** Retinoblastoma (RB) is the most common primary intraocular malignancy of childhood. Understanding the genetic basis is crucial for NEET-PG, specifically **Knudson’s "Two-Hit" Hypothesis**. **Why Option B is Correct:** Familial (heritable) retinoblastoma occurs due to a germline mutation in the **RB1 gene** on chromosome **13q14**. In these cases, the "first hit" is present in every cell of the body. A "second hit" (somatic mutation) occurs early in retinal development. Because the germline mutation is ubiquitous, there is a high probability of multiple tumors developing in both eyes. Thus, familial RB is **characteristically bilateral (and often multifocal)**. **Analysis of Incorrect Options:** * **Option A:** Familial RB follows an **autosomal dominant** inheritance pattern with high penetrance (90%), not autosomal recessive. * **Option C:** While it is due to a mutation, Option B is a more specific clinical descriptor of the familial form. (Note: In many exams, "More commonly bilateral" is the classic distinguishing feature tested). * **Option D:** Sporadic (non-heritable) retinoblastoma is actually **more common**, accounting for approximately **60%** of all cases, whereas familial cases account for about 40%. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presenting sign:** Leukocoria (White pupillary reflex). Second most common: Strabismus. * **Pathology:** Look for **Flexner-Wintersteiner rosettes** (highly specific) and Homer-Wright rosettes. * **Trilateral Retinoblastoma:** Bilateral RB associated with a pinealoblastoma. * **Calcification:** RB is the most common cause of intraocular calcification in a child under 3 years (visible on CT scan). * **Risk:** Patients with familial RB have a high predisposition to secondary non-ocular tumors, most commonly **Osteosarcoma**.

Question 1

All are macular function tests except?

Accepted Answer

Scanning laser polarimetry

Answer

Colour Vision

Answer

Visual acuity

Answer

Entoptic phenomenon

Question 2

Which condition is associated with HLA-A29?

Accepted Answer

Birdshot retinochoroidopathy

Answer

Serpiginous geographical choroidopathy

Answer

Sympathetic ophthalmitis

Answer

Acute posterior multifocal placoid pigment epitheliopathy

Question 3

Which of the following statements regarding Retinopathy of Prematurity is true?

Accepted Answer

Most cases resolve spontaneously.

Answer

It is classified in 4 stages based on severity.

Answer

Based on anatomical location, Zone 3 includes the nasal retina.

Answer

Polyhydramnios is a risk factor.

Question 4

What is the most common cause of gradual vision loss in Diabetic Retinopathy?

Accepted Answer

Macular edema

Answer

Cataract

Answer

Glaucoma

Answer

Keratoconus

Question 5

Cotton wool spots are seen in which of the following conditions?

Accepted Answer

Diabetic retinopathy, Hypertensive retinopathy, AIDS, Toxemia of pregnancy

Answer

Diabetic retinopathy, Hypertensive retinopathy, AIDS, Retinoblastoma

Answer

Diabetic retinopathy, AIDS, Retinoblastoma, Toxemia of pregnancy

Answer

Diabetic retinopathy, Hypertensive retinopathy, Retinoblastoma, Toxemia of pregnancy

Question 6

Examination of the fundus shows a cherry-red spot in all of the following conditions, EXCEPT:

Accepted Answer

Central retinal vein occlusion

Answer

Gaucher's disease

Answer

Tay-Sachs disease

Answer

Niemann-Pick disease

Question 7

Which of the following is NOT seen in Central Retinal Artery (CRA) occlusion?

Accepted Answer

Gradual loss of vision

Answer

Headache

Answer

Sudden loss of vision

Answer

Retained central vision

Question 8

Which of the following statements about asteroid hyalosis is false?

Accepted Answer

Is typically unilateral.

Answer

Consists of calcium bodies in the vitreous cavity.

Answer

Is a degenerative condition of the eye.

Answer

All of the above.

Question 9

Which of the following statements regarding familial retinoblastoma are correct?

Accepted Answer

More commonly bilateral

Answer

Has autosomal recessive inheritance

Answer

Due to mutation

Answer

More common than sporadic retinoblastoma

Question 10

Which of the following is a characteristic sign of diabetic retinopathy?

Accepted Answer

Proliferation of endothelial cells

Answer

Increase in pericytes

Answer

Thinned out capillary basement membrane

Answer

Lipohyaline deposits

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

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