Diseases of the Retina Practice Questions

Q: . A patient presented with sudden loss of vision with the retinal findings as shown in the image. What is the most probable diagnosis?

CRAO. ***CRAO*** - Central Retinal Artery Occlusion (CRAO) typically presents as **sudden, painless, monocular vision loss** due to an embolic or thrombotic blockage of the retinal arterial supply. - The characteristic **fundus appearance** includes **pale, edematous retina** (due to ischemia) with a pathognomonic **cherry-red spot** at the fovea, where the underlying choroidal circulation remains visible. *CRVO* - Central Retinal Vein Occlusion (CRVO) presents with a **'blood and thunder' fundus** characterized by widespread **retinal hemorrhages**, dilated and tortuous veins, and cotton wool spots. - Unlike CRAO, CRVO is caused by venous obstruction, leading to backup of blood rather than the ischemic whitening seen in arterial occlusion. *Retinal detachment* - Commonly presents with symptoms of **'flashes' (photopsia)**, **'floaters'**, and a **'curtain-like' visual field defect** rather than sudden total loss. - Funduscopy reveals a **gray, elevated retina** with folds, lacking the specific cherry-red spot morphology associated with CRAO. *Vitreous hemorrhage* - Presents with sudden vision loss that is often described as a **reddish haze** or loss of the **red reflex** during ophthalmoscopy. - The fundus details—such as the optic disc and vessels—become **obscured or invisible** due to the blood filling the vitreous cavity, which distinguishes it from the clear but pale view in CRAO.

Q: The outer blood-retinal barrier is formed by which structure?

Retinal pigment epithelium. ### Explanation The **Blood-Retinal Barrier (BRB)** is a physiological barrier that regulates the movement of fluids and nutrients into the retina, maintaining a dry environment essential for clear vision. It consists of two distinct components: 1. **Outer Blood-Retinal Barrier (Correct Option C):** This is formed by the **Retinal Pigment Epithelium (RPE)**. The RPE cells are joined by **tight junctions (Zonula occludens)**, which prevent the leakage of large molecules and fluid from the underlying fenestrated choriocapillaris into the subretinal space. 2. **Inner Blood-Retinal Barrier:** This is formed by the **non-fenestrated endothelial cells** of the retinal capillaries. These cells also utilize tight junctions to prevent leakage from the retinal circulation. #### Analysis of Incorrect Options: * **Option A (Internal Limiting Membrane):** This is the innermost layer of the retina, formed by the basement membrane of Müller cells. It separates the retina from the vitreous but does not function as a blood barrier. * **Option B (Endothelium):** While endothelial cells form the *Inner* BRB, they do not form the *Outer* BRB. * **Option D (Ganglion cells):** These are the second-order neurons of the visual pathway; they have no structural role in forming physiological barriers. #### High-Yield Clinical Pearls for NEET-PG: * **Breakdown of Outer BRB:** Leads to conditions like **Central Serous Chorioretinopathy (CSCR)** and **Exudative Age-related Macular Degeneration (AMD)**. * **Breakdown of Inner BRB:** Leads to **Macular Edema** (e.g., Diabetic Retinopathy, RVO). * **Fluorescein Angiography (FFA):** The "background glow" or choroidal flush seen in FFA is due to the fenestrated nature of the choriocapillaris, while the RPE acts as a filter (the "RPE screen effect").

Q: About retinitis pigmentosa, all are true EXCEPT?

Central scotoma. **Explanation:** Retinitis Pigmentosa (RP) is a hereditary, progressive dystrophy primarily affecting the **rod photoreceptors** (rod-cone dystrophy). Because rods are concentrated in the mid-periphery of the retina, the disease typically begins there and spares the central cone-rich macula until the very late stages. **Why "Central Scotoma" is the correct answer (the exception):** In RP, the initial visual field defect is an isolated scotoma in the mid-periphery. These scotomas eventually coalesce to form a **Ring Scotoma**. As the disease progresses, the field constricts further, leading to "tubular vision." **Central scotoma** is characteristic of macular diseases (like ARMD or Stargardt disease) or optic nerve pathologies, not typical RP, where central vision is usually preserved until the end-stage. **Analysis of other options:** * **Ring Scotoma (Option A):** This is the classic visual field defect in RP, resulting from the circumferential degeneration of rods in the mid-peripheral retina. * **Waxy Pallor of Disc (Option C):** Part of the "Classic Triad" of RP. It is caused by glial proliferation over the optic nerve head (gliosis), rather than true optic atrophy. * **Bone Spicule Pigmentation (Option D):** Part of the "Classic Triad." It occurs due to the migration of pigment from the Retinal Pigment Epithelium (RPE) into the sensory retina, typically following a perivascular distribution in the mid-periphery. **NEET-PG High-Yield Pearls:** 1. **Classic Triad:** (1) Bone spicule pigmentation, (2) Waxy pallor of the disc, (3) Arteriolar attenuation (narrowing). 2. **Earliest Symptom:** Nyctalopia (Night blindness). 3. **Earliest Sign:** Exhaustion of the a-wave on Electroretinogram (ERG). Note: ERG is subnormal or extinguished. 4. **Inheritance:** Most common is Autosomal Recessive; most severe is X-linked Recessive. 5. **Associated Systemic Syndrome:** Usher Syndrome (RP + Sensorineural deafness) is the most common.

Q: In cystoid macular edema, fluid collects in the macular region at the level of which layer?

Outer plexiform layer. ### Explanation **Cystoid Macular Edema (CME)** is characterized by the accumulation of fluid in the macula, leading to the formation of cyst-like spaces. **1. Why the Outer Plexiform Layer (OPL) is correct:** In the macular region, the fibers of the outer plexiform layer are oriented obliquely; these are known as **Henle’s layer**. Because of this loose, radial arrangement, the OPL has a high capacity to accumulate extracellular fluid. In CME, fluid primarily collects in these spaces, creating the characteristic **"petaloid" pattern** seen on Fluorescein Angiography (FA). **2. Analysis of Incorrect Options:** * **Outer Nuclear Layer (A):** While some fluid may involve the inner nuclear layer in chronic cases, the primary and initial site of collection is the plexiform layer. * **Inner Plexiform Layer (C):** This layer is more compact and is not the primary site for fluid accumulation in CME. * **Between RPE and Neurosensory Retina (D):** This describes a **Subretinal Detachment** (e.g., Central Serous Chorioretinopathy), not intraretinal edema. **3. High-Yield Clinical Pearls for NEET-PG:** * **Pathophysiology:** Breakdown of the blood-retinal barrier (usually the inner barrier/retinal capillaries). * **Gold Standard Diagnosis:** **Optical Coherence Tomography (OCT)**, which shows "honeycomb" cystic spaces. * **Fluorescein Angiography (FA):** Shows a classic **Flower-petal appearance** due to the radial arrangement of Henle’s layer. * **Irvine-Gass Syndrome:** CME occurring specifically after cataract surgery (typically 4–6 weeks post-op). * **Common Causes:** Diabetes (DME), Uveitis, Retinal Vein Occlusion (RVO), and Prostaglandin analogues (Latanoprost).

Q: Waves present in electroretinogram are all EXCEPT:

d wave. **Explanation:** The **Electroretinogram (ERG)** is a diagnostic test that measures the electrical response of various cell layers in the retina to a light stimulus. A standard ERG waveform consists of three primary components: **a, b, and c waves.** * **Correct Answer (D):** The **d-wave** is not considered a standard component of the clinical ERG waveform. While some specialized research contexts refer to a "d-wave" as an "off-response" (occurring when the light stimulus is turned off), it is not part of the classic clinical ERG used to assess retinal function in standard examinations. **Analysis of Other Options:** * **A. a-wave:** This is the first **negative** deflection. It represents the activity of the **photoreceptors** (rods and cones) in the outer retinal layer. * **B. b-wave:** This is the large **positive** deflection following the a-wave. It is the most clinically significant wave and represents the health of the **inner retinal layers**, specifically the **Müller cells and Bipolar cells.** * **C. c-wave:** This is a prolonged, lower-amplitude positive wave following the b-wave. It originates from the **Retinal Pigment Epithelium (RPE)** in response to changes in subretinal potassium concentration. **High-Yield Clinical Pearls for NEET-PG:** * **Origin Summary:** a-wave (Photoreceptors), b-wave (Bipolar/Müller cells), c-wave (RPE). * **Oscillatory Potentials:** These are small ripples found on the ascending limb of the b-wave, originating from **Amacrine cells**. They are characteristically lost early in **Diabetic Retinopathy**. * **Negative ERG:** A condition where the a-wave is preserved but the b-wave is significantly reduced or absent. This is classically seen in **Central Retinal Artery Occlusion (CRAO)** and **Congenital Stationary Night Blindness (CSNB)**. * **EOG (Electro-oculogram):** Measures RPE function; the key parameter is the **Arden Index** (Normal > 1.8).

Q: Which of the following is not a high-risk characteristic in proliferative diabetic retinopathy?

NVD + Clinically significant macular edema. The correct answer is **D. NVD + Clinically significant macular edema**. ### **Explanation** The concept of **High-Risk Characteristics (HRC)** was defined by the **Diabetic Retinal Study (DRS)** to identify patients at a high risk of severe visual loss who require urgent Pan-Retinal Photocoagulation (PRP). While Clinically Significant Macular Edema (CSME) is a major cause of vision loss in diabetic patients, it is **not** a criterion for "High-Risk Proliferative Diabetic Retinopathy (PDR)." CSME can occur at any stage of diabetic retinopathy (NPDR or PDR) and is treated with focal/grid lasers or anti-VEGF agents, whereas HRC-PDR specifically dictates the need for PRP. ### **Analysis of Options** According to the DRS, HRC is defined by the presence of **three or more** of the following four risk factors, or specifically the combinations listed below: * **Option A:** New vessels on the disc (NVD) $\geq$ 1/3 to 1/2 of the disc area (even without hemorrhage). * **Option B:** Any amount of NVD associated with vitreous or preretinal hemorrhage. * **Option C:** New vessels elsewhere (NVE) $\geq$ 1/2 disc area **AND** the presence of vitreous or preretinal hemorrhage. ### **Clinical Pearls for NEET-PG** * **Standard Treatment:** The presence of HRC is the absolute indication for **Pan-Retinal Photocoagulation (PRP)**. * **NVD vs. NVE:** NVD carries a much higher risk of vision loss than NVE; hence, smaller amounts of NVD qualify as high-risk compared to NVE. * **CSME Definition (ETDRS):** 1. Retinal thickening within 500 $\mu$m of the center of the macula. 2. Hard exudates within 500 $\mu$m of the center (with adjacent thickening). 3. Retinal thickening $\geq$ 1 disc area in size, any part of which is within 1 disc diameter of the center.

Q: Examination of the vitreous is best performed by which of the following methods?

Indirect ophthalmoscope. **Explanation:** The examination of the vitreous requires a technique that provides a wide field of view, excellent illumination, and stereopsis (depth perception) to visualize the transparent gel and any associated pathologies. **Why Indirect Ophthalmoscopy is the Correct Answer:** The **Indirect Ophthalmoscope** is the gold standard for a comprehensive evaluation of the vitreous cavity. It utilizes a strong light source and a condensing lens (typically 20D) to provide a **wide-angled, stereoscopic, and bright image**. This allows the examiner to visualize the vitreous from the anterior hyaloid face all the way to the peripheral retina (ora serrata), making it superior for detecting vitreous opacities, hemorrhages, or membranes. **Analysis of Incorrect Options:** * **A. Direct Ophthalmoscope:** While it provides high magnification, it lacks stereopsis and has a very narrow field of view (about 5-10 degrees), making it ineffective for surveying the three-dimensional vitreous volume. * **C. Slit-lamp with a contact lens:** While a slit-lamp with a Hruby lens or a Goldmann 3-mirror lens provides excellent detail of the posterior vitreous and vitreoretinal interface, the **Indirect Ophthalmoscope** remains the primary and best method for a global, comprehensive examination of the entire vitreous body. * **D. Oblique illumination:** This is a basic technique used primarily for the anterior segment (cornea, iris, lens) and cannot penetrate or visualize the vitreous cavity effectively. **High-Yield Clinical Pearls for NEET-PG:** * **Shafer’s Sign:** The presence of "tobacco dust" (RPE cells) in the anterior vitreous on slit-lamp exam is a pathognomonic sign of a retinal tear. * **Weiss Ring:** A ring-shaped opacity in the vitreous indicating a posterior vitreous detachment (PVD). * For the **extreme periphery** of the vitreous/retina, indirect ophthalmoscopy combined with **scleral indentation** is the technique of choice.

Question 1

. A patient presented with sudden loss of vision with the retinal findings as shown in the image. What is the most probable diagnosis?

Accepted Answer

CRAO

Answer

CRVO

Answer

Retinal detachment

Answer

Vitreous hemorrhage

Question 2

A 52-year-old woman with a 15-year history of poorly controlled type 2 diabetes mellitus presents with gradual blurring of central vision in both eyes over the past 6 months. Her HbA1c is 10.2%. Fundus examination reveals dot-blot haemorrhages and hard exudates in the macular region bilaterally. Her best-corrected visual acuity is 6/24 in the right eye. The OCT is shown (Image 2). According to current evidence-based guidelines, which of the following represents the most appropriate first-line treatment for the condition demonstrated on imaging in this eye?

Accepted Answer

A. Intravitreal anti-VEGF injection (e.g., ranibizumab or bevacizumab)

Answer

B. Focal/grid macular laser photocoagulation to all areas of retinal thickening

Answer

C. Intravitreal triamcinolone acetonide as monotherapy

Answer

D. Pars plana vitrectomy with internal limiting membrane peeling

Question 3

A 62-year-old man with a family history of glaucoma attends a routine eye clinic. He reports no visual symptoms. Intraocular pressure is 26 mmHg in the right eye. Gonioscopy reveals an open angle. The appearance of the right-eye optic disc is shown in Image 2 (standard fundus orientation: superior disc pole at top, inferior disc pole at bottom, nasal side to the right). Automated perimetry reveals an arcuate scotoma in the superior field. Which of the following best describes the structural finding visible in the image that accounts for this visual field loss?

Accepted Answer

A. Inferior neuroretinal rim loss with violation of the ISNT rule, consistent with preferential damage to the inferior disc pole

Answer

B. Superior neuroretinal rim loss with an enlarged blind spot, consistent with preferential damage to the superior disc pole

Answer

C. Diffuse concentric enlargement of the cup with preserved neuroretinal rim tissue at all poles

Answer

D. Nasal displacement of vessels with superior rim thinning, consistent with a compressive optic neuropathy

Question 4

The outer blood-retinal barrier is formed by which structure?

Accepted Answer

Retinal pigment epithelium

Answer

Internal limiting membrane

Answer

Endothelium

Answer

Ganglion cells

Question 5

About retinitis pigmentosa, all are true EXCEPT?

Accepted Answer

Central scotoma

Answer

Ring scotoma

Answer

Waxy pallor of disc

Answer

Bone spicule pigmentation in retina

Question 6

In cystoid macular edema, fluid collects in the macular region at the level of which layer?

Accepted Answer

Outer plexiform layer

Answer

Outer nuclear layer

Answer

Inner plexiform layer

Answer

Between pigment epithelium and neurosensory retina

Question 7

Waves present in electroretinogram are all EXCEPT:

Accepted Answer

d wave

Answer

a wave

Answer

b wave

Answer

c wave

Question 8

Which of the following is not a high-risk characteristic in proliferative diabetic retinopathy?

Accepted Answer

NVD + Clinically significant macular edema

Answer

NVD >= 1/3 - 1/2 disc area

Answer

NVD + Vitreous or Preretinal haemorrhage

Answer

NVE >= 1/2 disc area and Preretinal or Vitreous haemorrhage

Question 9

A 60-year-old man with a 10-year history of hypertension and diabetes mellitus presents with reduced vision in one eye. Fundus examination reveals a central bleed, while the fellow eye is normal. What is the most likely diagnosis?

Accepted Answer

Diabetic retinopathy

Answer

Retinal tear

Answer

Optic neuritis

Answer

Hypertensive retinopathy

Question 10

Examination of the vitreous is best performed by which of the following methods?

Accepted Answer

Indirect ophthalmoscope

Answer

Direct ophthalmoscope

Answer

Slit-lamp with a contact lens

Answer

Oblique illumination

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

On this page

Practice by Chapter

Want unlimited practice?