Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 481: A child presents with night blindness, delayed dark adaptation. Which investigation is to be done further to confirm the diagnosis?

A. ERG (Correct Answer)
B. Retinoscopy
C. Dark adaptometry
D. EOG

Explanation: ***ERG*** - **Electroretinography (ERG)** measures the electrical responses of various retinal cells, including **rods** and **cones**, to light stimuli. - In conditions like **retinitis pigmentosa** which cause night blindness and delayed dark adaptation, ERG will show characteristic abnormal or extinguished responses, confirming retinal dysfunction. *Retinoscopy* - **Retinoscopy** is an objective method to assess the refractive error of the eye by observing the light reflex from the retina. - It does not directly evaluate the functional integrity of photoreceptors or diagnose conditions causing **night blindness**. *Dark adaptometry* - **Dark adaptometry** measures the time it takes for the eye to adapt to dim light after exposure to bright light, quantifying the function of **rod photoreceptors**. - While it can *detect* delayed dark adaptation, it is a functional test that assesses the symptom, not the underlying cause provided by ERG. *EOG* - **Electrooculography (EOG)** measures the potential difference between the cornea and the retina, primarily assessing the function of the **retinal pigment epithelium (RPE)**. - While useful for conditions like **Best's disease**, it is less direct for evaluating generalized rod dysfunction causing night blindness compared to ERG.

Question 482: Optic disc changes of retinitis pigmentosa:

A. Hyperemia of disc
B. Consecutive optic atrophy (Correct Answer)
C. No significant change
D. Blurring of disc margins

Explanation: **Consecutive optic atrophy** - In **retinitis pigmentosa**, the progressive degeneration of photoreceptors and retinal pigment epithelium leads to secondary or **consecutive optic atrophy**. - This atrophy is characterized by a **pale, waxy optic disc** due to loss of retinal ganglion cell axons and glia. *Hyperemia of disc* - **Hyperemia of the optic disc** indicates **inflammation** or **swelling** of the optic nerve head, such as in optic neuritis or papilledema. - This is not a typical feature of retinitis pigmentosa, which involves retinal degeneration, not acute inflammation of the optic nerve. *No significant change* - As **retinitis pigmentosa** progresses, significant changes occur in the retina and optic nerve, including **pigmentary deposits**, **vascular attenuation**, and **optic disc pallor**. - Therefore, stating no significant change would be incorrect as the disease significantly alters the fundus appearance. *Blurring of disc margins* - **Blurring of the optic disc margins** is a hallmark sign of **papilledema** (swelling due to increased intracranial pressure) or an acutely inflamed optic nerve head. - This is distinct from the **optic atrophy** seen in retinitis pigmentosa, which typically involves clear but pale disc margins.

Question 483: Cause of sudden loss of vision in a diabetic is due to:

A. Central retinal vein occlusion
B. Neovascular glaucoma
C. Vitreous hemorrhage (Correct Answer)
D. Central retinal artery occlusion

Explanation: ***Vitreous hemorrhage*** - **Vitreous hemorrhage** is the **most common cause** of sudden, painless vision loss in individuals with **proliferative diabetic retinopathy** - New, fragile blood vessels (neovascularization) on the retina in diabetes can rupture, leading to bleeding into the **vitreous gel** - Patients describe sudden onset of floaters, cobwebs, or a red haze obscuring vision *Central retinal vein occlusion* - **CRVO** causes sudden, painless vision loss with **retinal hemorrhages in all four quadrants** (blood and thunder appearance) - While diabetic patients are at increased risk, vision loss is typically less profound than vitreous hemorrhage - Fundoscopy shows widespread retinal hemorrhages, dilated tortuous veins, and cotton-wool spots *Neovascular glaucoma* - **Neovascular glaucoma** causes **painful** vision loss and elevated intraocular pressure due to new vessel growth on the iris and trabecular meshwork - While associated with diabetes, it usually presents with more **gradual onset** and pain, rather than sudden, painless vision loss - Characterized by rubeosis iridis and elevated IOP *Central retinal artery occlusion* - **CRAO** causes sudden, profound, painless monocular vision loss, often described as a "curtain coming down" - While diabetic patients are at higher risk for CRAO due to generalized atherosclerosis, it typically results in a **cherry-red spot** on the macula - This is usually embolic in nature and less specifically related to diabetic retinopathy itself

Question 484: Pupil in acute iritis is:

A. Dilated
B. Normal
C. Constricted (Correct Answer)
D. Vertically oval

Explanation: ***Constricted*** - In acute iritis, the pupil is typically **constricted (miotic)** due to ciliary muscle spasm and release of inflammatory mediators like prostaglandins. - This constriction helps to **reduce photophobia** and pain by limiting the amount of light entering the eye. *Dilated* - A dilated pupil (mydriasis) is usually seen in conditions like **acute angle-closure glaucoma** or due to certain medications, not iritis. - In iritis, the inflammatory process *actively* causes constriction. *Normal* - A normal pupil size would not be expected in acute iritis, as inflammation always causes some degree of **miosis** or other pupillary abnormality. - Acute iritis presents with significant symptoms that affect pupillary function. *Vertically oval* - A vertically oval pupil can be seen in specific conditions such as **acute angle-closure glaucoma** in some individuals, particularly with high intraocular pressure. - It is not a characteristic feature of iritis.

Question 485: Which of the following is seen in retinitis pigmentosa?

A. Arteriolar attenuation (Correct Answer)
B. Neovascularization
C. Papilledema
D. Retinal artery thrombosis

Explanation: ***Arteriolar attenuation*** - **Arteriolar attenuation** is a classic finding in retinitis pigmentosa, reflecting the progressive loss of retinal tissue and the associated reduction in metabolic demand, leading to narrowing of the retinal arterioles. - This sign indicates the ongoing degeneration of photoreceptors and the underlying retinal layers, which is characteristic of the disease. *Neovascularization* - **Neovascularization** (abnormal new blood vessel growth) is typically associated with conditions like proliferative diabetic retinopathy or age-related macular degeneration. - It is not a primary feature of retinitis pigmentosa, which is a degenerative disease rather than an ischemic or proliferative one. *Papilledema* - **Papilledema** is swelling of the optic disc due to increased intracranial pressure. - It is not a feature of retinitis pigmentosa; rather, the optic disc in retinitis pigmentosa often appears waxy pale due to optic atrophy. *Retinal artery thrombosis* - **Retinal artery thrombosis** involves the sudden blockage of a retinal artery, leading to acute vision loss and often presenting with a 'cherry-red spot' on the macula. - This is an acute vascular event and is not characteristic of the chronic, progressive degeneration seen in retinitis pigmentosa.

Question 486: Arden index is related to

A. ERG (Electroretinogram)
B. VER (Visual Evoked response)
C. Perimetry
D. EOG (Electrooculogram) (Correct Answer)

Explanation: ***EOG (Electrooculogram)*** - The **Arden index** is a measure derived from the **electrooculogram (EOG)**, which assesses the function of the **retinal pigment epithelium (RPE)**. - It represents the ratio of the maximum light peak to the minimum dark trough recorded during EOG, with a normal value typically above 1.8. *ERG (Electroretinogram)* - The **electroretinogram (ERG)** measures the **electrical responses of photoreceptors and other retinal cells** to light stimuli. - While it assesses retinal function, it does not directly yield the Arden index; that is specific to EOG readings. *VER (Visual Evoked response)* - **Visual evoked response (VER)** or **VEP (visual evoked potential)** measures the **electrical activity in the brain's visual cortex** in response to visual stimuli. - It assesses the integrity of the visual pathway from the optic nerve to the cortex, not directly the function of the RPE or the Arden index. *Perimetry* - **Perimetry**, or **visual field testing**, maps the sensitivity of the entire visual field, helping to detect deficits in peripheral or central vision. - It evaluates the functional extent of vision rather than the electrical activity of specific retinal layers or the RPE as assessed by the Arden index.

Question 487: One year old male child with cat's reflex and raised IOP. What is the most likely diagnosis?

A. Toxocara canis
B. Retinopathy of prematurity
C. Retinoblastoma (Correct Answer)
D. Toxoplasma gondii infection

Explanation: ***Retinoblastoma*** - A **cat's reflex (leukocoria)**, which is a white pupillary reflex, is the most common presenting sign of retinoblastoma in children. - **Raised intraocular pressure (IOP)** can occur in advanced retinoblastoma due to secondary glaucoma caused by tumor growth or neovascularization. *Toxocara canis* - Ocular **toxocariasis** can cause leukocoria and inflammation, but it's typically associated with **granuloma formation** and not usually primary elevated IOP. - This condition is caused by a **parasitic infection** from roundworms, often seen in children with exposure to contaminated soil or pets. *Retinopathy of prematurity* - Primarily affects **premature infants** exposed to high oxygen, leading to abnormal retinal vessel development. - While it can cause leukocoria in severe stages, it would be unusual for a **one-year-old** to present with this primary diagnosis especially with raised IOP. *Toxoplasma gondii infection* - Ocular **toxoplasmosis** typically presents with **chorioretinitis** and can cause inflammation, but **leukocoria** and **raised IOP** are not its primary or most characteristic features. - This is a parasitic infection, congenital or acquired, often presenting with **retinal scars**.

Question 488: The laser procedure, most often used for treating iris neovascularization is

A. Panretinal photocoagulation (PRP) (Correct Answer)
B. Laser iridoplasty
C. Laser trabeculoplasty
D. Goniophotocoagulation

Explanation: ***Panretinal photocoagulation (PRP)*** - **PRP** is the most effective laser procedure for **iris neovascularization** and **neovascular glaucoma**, as it ablates the ischemic retina, reducing the production of **vascular endothelial growth factor (VEGF)**. - By destroying the ischemic peripheral retina, PRP reduces the **angiogenic drive** that leads to new vessel formation on the iris and in the angle. *Laser iridoplasty* - This procedure involves applying laser energy to the peripheral iris to cause contraction and widen the **anterior chamber angle**, primarily used for **angle-closure glaucoma**. - While it can open a closed angle, it does not address the underlying **ischemic drive** causing neovascularization. *Laser trabeculoplasty* - This procedure targets the **trabecular meshwork** to improve aqueous humor outflow, commonly used for **open-angle glaucoma**. - It does not directly affect **iris neovascularization** or the ischemic factors driving its development. *Goniophotocoagulation* - This involves directly lasering new vessels in the **anterior chamber angle**, often as an adjunct to PRP, but it's not the primary treatment to prevent **iris neovascularization**. - It treats existing vessels but does not address the underlying cause of **retinal ischemia** that promotes new vessel growth.

Question 489: Expulsive choroidal haemorrhage is caused by rupture of:

A. The choriocapillaris
B. Retinal vessels
C. Long posterior ciliary arteries
D. Short posterior ciliary arteries (Correct Answer)

Explanation: ***Short posterior ciliary arteries*** - **Expulsive choroidal hemorrhage** is a rare but devastating complication of intraocular surgery, most commonly cataract surgery. It is characterized by acute severe pain, loss of vision, and rapid prolapse of intraocular contents. - The rapid increase in **intraocular pressure** during surgery, often due to sudden decompression of the globe, can lead to the rupture of these relatively larger, high-pressure vessels, causing a massive hemorrhage. *The choriocapillaris* - The **choriocapillaris** is a dense network of fenestrated capillaries located in the inner choroid, primarily responsible for nourishing the outer retina. - While rupture of the choriocapillaris can lead to hemorrhage, the resulting bleeding is typically less extensive and less "expulsive" compared to that originating from larger, higher-pressure arteries. *Retinal vessels* - **Retinal vessels** are located within the retina itself and are separate from the choroidal circulation. Rupture of retinal vessels typically leads to **vitreous hemorrhage** or **retinal hemorrhage**. - Retinal hemorrhages, while serious, do not typically cause the massive, expulsive bleeding seen with choroidal hemorrhage, as they are not under the same high pressure and do not directly contribute to the choroidal blood volume. *Long posterior ciliary arteries* - The **long posterior ciliary arteries** primarily supply the anterior choroid and iris, running within the suprachoroidal space. - While important for ocular blood supply, their rupture is less commonly associated with the sudden, massive, and expulsive hemorrhage characteristic of expulsive choroidal hemorrhage, which typically involves the more posterior and larger caliber short posterior ciliary arteries.

Question 490: Ocriplasmin is a recombinant protease and it is used to treat:

A. Submacular bleeding
B. Diabetic macular edema
C. Retinal break
D. Vitreomacular adhesion (VMA) (Correct Answer)

Explanation: ***Vitreomacular adhesion (VMA)*** - **Ocriplasmin** is a *recombinant protease* specifically approved for the treatment of symptomatic **vitreomacular adhesion (VMA)** or *vitreomacular traction (VMT)*. - Its proteolytic activity helps dissolve the proteins at the vitreomacular interface, thereby releasing the traction and potentially preventing progression to other macular pathologies like *macular holes*. *Submacular bleeding* - **Submacular bleeding** is typically managed with anti-VEGF injections, *vitrectomy with subretinal tissue plasminogen activator (tPA)*, or pneumatic displacement, not ocriplasmin. - The goal is to displace or remove blood, which is not the primary mechanism of action for ocriplasmin. *Diabetic macular edema* - **Diabetic macular edema (DME)** is commonly treated with *anti-VEGF agents* (e.g., ranibizumab, aflibercept), corticosteroids, or laser photocoagulation. - DME is characterized by fluid leakage and swelling due to diabetic retinopathy, not vitreomacular adhesion. *Retinal break* - A **retinal break** (tear or hole) is typically managed with *laser photocoagulation* or *cryopexy* to create an adhesion around the break and prevent retinal detachment. - Ocriplasmin does not have a role in the direct treatment or repair of retinal breaks.

Practice by Chapter

Retinal Anatomy and Physiology

Practice Questions

Age-Related Macular Degeneration

Practice Questions

Diabetic Retinopathy

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Retinal Vascular Diseases

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Retinal Detachment

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Hereditary Retinal Dystrophies

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Inflammatory Retinal Diseases

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Retinal Tumors

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Retinopathy of Prematurity

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Retinal Imaging Techniques

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Intravitreal Pharmacotherapy

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Vitreoretinal Surgery

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