Diseases of the Retina — MCQs

Diseases of the Retina Indian Medical PG Practice Questions and MCQs

Question 491: All are ophthalmological emergencies except -

A. Endophthalmitis
B. CRVO (Correct Answer)
C. Acute congestive glaucoma
D. CRAO

Explanation: ***CRVO*** - Central Retinal Vein Occlusion (CRVO) is characterized by painless **vision loss** due to retinal hemorrhage and edema, but it is generally *not* considered an immediate, vision-threatening emergency in the same vein as the other options. - While it requires prompt evaluation and management to preserve vision, CRVO allows for a less urgent intervention compared to conditions that can lead to permanent vision loss within hours. *Endophthalmitis* - **Endophthalmitis** is a severe inflammation of the intraocular fluids and tissues, typically caused by infection, and can lead to rapid and irreversible vision loss if not treated urgently. - It presents with pain, redness, reduced vision, and hypopyon (pus in the anterior chamber), necessitating immediate antibiotic treatment and surgical intervention. *Acute congestive glaucoma* - **Acute congestive glaucoma** (acute angle-closure glaucoma) involves a sudden increase in intraocular pressure, causing severe pain, redness, corneal edema, and profound vision loss. - If left untreated, the high pressure can cause irreversible damage to the optic nerve within hours, making it a true ocular emergency. *CRAO* - **Central Retinal Artery Occlusion (CRAO)** is a sudden, painless loss of vision in one eye due to blockage of the central retinal artery, leading to retinal ischemia. - It is an ocular emergency because irreversible retinal damage and vision loss can occur within 90-120 minutes of the occlusion, requiring immediate intervention to restore blood flow.

Question 492: Phthisis bulbi is characterized by -

A. Developmental hypoplasia of optic cup
B. Final end stage of chronic uveitis (Correct Answer)
C. Final end stage of chronic scleritis
D. All of the above

Explanation: ***Correct: Final end stage of chronic uveitis*** - **Phthisis bulbi** is a shrunken, atrophic, disorganized, and non-functional eye representing the end stage of severe ocular disease - **Chronic uveitis** is one of the **most common causes** of phthisis bulbi, as prolonged intraocular inflammation leads to: - Destruction of intraocular structures - **Hypotony** (reduced intraocular pressure) - Globe shrinkage and disorganization - Complete loss of vision - While phthisis bulbi can result from multiple severe conditions (trauma, infection, end-stage glaucoma), **chronic uveitis** remains the most frequent inflammatory cause *Incorrect: Developmental hypoplasia of optic cup* - This describes a **congenital anomaly** (microphthalmia) where the eye is small from birth - Phthisis bulbi is an **acquired condition** resulting from destructive ocular disease - The eye shrinks secondarily after birth, not due to developmental failure - Completely different pathophysiology and timing *Incorrect: Final end stage of chronic scleritis* - While severe chronic scleritis **can** contribute to phthisis bulbi through: - Scleral thinning and perforation - Secondary uveitis - Secondary glaucoma - It is **less commonly** the primary direct cause compared to chronic uveitis - Scleritis primarily affects the sclera, whereas uveitis causes more extensive intraocular destruction *Incorrect: All of the above* - Option A (developmental hypoplasia) is a congenital condition, NOT phthisis bulbi - Phthisis bulbi is specifically an acquired end-stage condition - Therefore, "all of the above" cannot be correct

Question 493: A-wave in Electroretinogram corresponds to the activity of

A. Pigment epithelium
B. Rods and cones (Correct Answer)
C. Nerve fibre layer
D. Ganglion cell layer

Explanation: ***Rods and cones*** - The **'a' wave** of the Electroretinogram (ERG) represents the **initial negative deflection**, primarily generated by the activity of the **photoreceptors** (rods and cones) in response to light stimulation. - This wave reflects the **hyperpolarization** of the photoreceptor cells as they absorb light and initiate the visual transduction cascade. *Pigment epithelium* - The **retinal pigment epithelium (RPE)** plays a crucial role in supporting photoreceptor function and has a slower, sustained electrical response, which contributes more to the **c-wave** of the ERG. - While the RPE is vital for retinal function, its primary electrical contribution is not represented by the initial negative a-wave. *Nerve fibre layer* - The **nerve fiber layer** consists of the axons of ganglion cells and does not directly contribute to the primary a-wave or b-wave of the ERG as it is involved in transmitting signals to the brain. - Damage to this layer may affect overall visual function but is not the source of the initial photoreceptor-driven electrical response. *Ganglion cell layer* - The **ganglion cell layer** is responsible for sending visual information to the brain, and its activity is typically reflected in later, more complex components of the ERG or in other electrophysiological tests like pattern ERG. - The initial photoreceptor response (a-wave) occurs upstream of the ganglion cell activity.

Question 494: True about sympathetic ophthalmia?

A. It is caused due to corneal injury
B. It is bilateral non granulomatous uveitis
C. Dalen Fuch's Nodules are seen (Correct Answer)
D. Paton's Lines are seen

Explanation: ***Dalen Fuch's Nodules are seen*** - **Dalen-Fuchs nodules** are characteristic histological findings in sympathetic ophthalmia, consisting of epithelioid cells and lymphocytes between the retinal pigment epithelium and Bruch's membrane. - Their presence is a key diagnostic indicator in the affected eye (sympathizing eye) and the exciting eye (initial injured eye). *It is caused due to corneal injury* - Sympathetic ophthalmia is typically triggered by **penetrating ocular trauma** or **intraocular surgery** involving the **uvea**, not merely corneal injury. - The exposure of **uveal antigens** to the immune system after injury is the initiating event. *It is bilateral non granulomatous uveitis* - Sympathetic ophthalmia is a **bilateral, granulomatous panuveitis**, meaning it involves all layers of the uvea and is characterized by granuloma formation. - The granulomatous nature with **epithelioid cells** and **giant cells** is a hallmark. *Paton's Lines are seen* - **Paton's lines** are radially oriented retinal folds seen around the optic disc, characteristic of **papilledema**. - They are not associated with sympathetic ophthalmia, which primarily affects the uvea and retina due to an autoimmune response.

Question 495: Pneumoretinopexy is an outpatient procedure in which retinal detachment is sealed with air insufflation. Which of the following gases is used in pneumoretinopexy?

A. Nitrous oxide
B. Oxygen
C. Sulfur hexafluoride (Correct Answer)
D. Carbon dioxide

Explanation: ***Sulfur hexafluoride*** - **Sulfur hexafluoride (SF6)** is a commonly used gas in **pneumatic retinopexy** due to its expansive properties and inertness within the eye. - It provides a **temporary tamponade effect** against the retinal tear, allowing the retina to reattach. - SF6 expands to approximately **twice its injected volume** and provides tamponade for **1-2 weeks**. - **Perfluoropropane (C3F8)** is another gas commonly used in pneumatic retinopexy, which lasts longer (6-8 weeks) but expands more (up to 4 times). *Nitrous oxide* - **Nitrous oxide** is primarily used as an **anesthetic gas** and for pain relief in medical procedures. - It is not suitable for intraocular tamponade due to its rapid absorption and potential to expand existing intraocular gas bubbles dangerously. *Oxygen* - **Oxygen** is essential for cellular respiration and is a fundamental component of the air we breathe. - It is **highly soluble** in intraocular fluids and would be quickly absorbed, making it ineffective for sustained retinal tamponade. *Carbon dioxide* - **Carbon dioxide** is a natural byproduct of metabolism and is used in some surgical contexts (e.g., laparoscopy) to create a working space. - Like oxygen, it is **highly soluble** and would dissipate too quickly to provide the necessary long-term tamponade for retinal reattachment.

Question 496: Indirect ophthalmoscopy is done for:

A. Macula and central retina
B. Periphery of retina (Correct Answer)
C. Sclera
D. Angle of anterior chamber

Explanation: ***Periphery of retina*** - Indirect ophthalmoscopy offers a **wide field of view** and **stereoscopic imaging**, making it ideal for examining the **peripheral retina**. - It allows for the detection of peripheral retinal lesions like **tears, detachments, and degenerations** that may be missed with direct ophthalmoscopy. *Macula and central retina* - While indirect ophthalmoscopy can visualize the macula, **direct ophthalmoscopy** provides a **higher magnification** and better resolution for detailed examination of the macula and optic disc. - Conditions like **macular degeneration** or **diabetic macular edema** are usually evaluated more precisely with direct ophthalmoscopy or specialized imaging. *Sclera* - The sclera is the **outer white layer of the eye**; its examination is primarily done through **external inspection** of the globe. - Ophthalmoscopy, whether direct or indirect, is focused on visualizing the **fundus** (retina, optic disc, blood vessels), not the sclera. *Angle of ant. chamber* - The **angle of the anterior chamber** is evaluated using **gonioscopy**, a specialized technique involving a contact lens with mirrors. - Ophthalmoscopy is not suitable for visualizing this structure, which is crucial for diagnosing and managing **glaucoma**.

Question 497: The shifting fluid sign is characteristic of which condition?

A. Exudative retinal detachment (Correct Answer)
B. Retinal hole
C. Tractional retinal detachment
D. Rhegmatogenous retinal detachment

Explanation: ***Exudative retinal detachment (fluid accumulation in subretinal space)*** - The **shifting fluid sign** is pathognomonic for **exudative retinal detachment**, as the subretinal fluid can move with changes in head position due to gravity. - This type of detachment is caused by conditions that lead to abnormal accumulation of fluid under the retina, such as **choroidal tumors**, inflammatory processes, or **severe hypertension**. *Retinal hole (localized retinal break)* - A **retinal hole** is a full-thickness defect in the retina, but it does not inherently cause a shifting fluid sign unless it progresses to a rhegmatogenous detachment. - While it can be a precursor to retinal detachment, the fluid itself is not subject to gravitational shifting in the same way as in exudative detachment. *Tractional retinal detachment (retinal pulling forces)* - **Tractional retinal detachments** occur when **fibrovascular membranes** on the retinal surface contract, pulling the retina away from the underlying choroid. - The detachment is usually localized and fixed by the tractional forces, meaning the fluid (if present) does not shift freely with changes in head position. *Rhegmatogenous retinal detachment (retinal break with vitreous fluid entry)* - This type of detachment involves a **retinal break** through which **liquefied vitreous** gains access to the subretinal space. - Although there is subretinal fluid, the fluid is generally trapped and the detachment is less mobile than in an exudative case; thus, a pronounced shifting fluid sign is not typical.

Question 498: TORCH infection most commonly causes:

A. Active chorioretinitis
B. Retinal detachment
C. Salt-pepper retinopathy (Correct Answer)
D. Optic atrophy

Explanation: ***Salt-pepper retinopathy*** - **Salt-pepper retinopathy** is a classic ophthalmologic sign of congenital TORCH infections, particularly **rubella** and **cytomegalovirus (CMV)**, and is characterized by diffuse pigmentary changes in the retina. - This appearance results from widespread retinal pigment epithelial (RPE) damage leading to both areas of depigmentation (salt) and hyperpigmentation (pepper). *Active chorioretinitis* - While TORCH infections, especially **toxoplasmosis**, can cause **chorioretinitis**, the term "active" implies acute inflammation with visible lesions, whereas **salt-pepper retinopathy** is a more chronic, widespread pigmentary change indicating past damage. - Active chorioretinitis often presents with specific focal, exudative lesions, not the diffuse pigmentary mottling seen in salt-pepper retinopathy. *Retinal detachment* - **Retinal detachment** is a possibility in severe cases of congenital infections if there are extensive chorioretinal scars or vitreoretinal traction, but it is not the most common or characteristic ocular finding. - It is a more severe complication, not the primary and typically milder retinal manifestation commonly expected from TORCH infections. *Optic atrophy* - **Optic atrophy** can occur as a sequela of severe congenital infections due to direct involvement of the optic nerve or secondary to widespread retinal damage, but it is less common than the classic **salt-pepper retinopathy**. - It indicates chronic damage to the optic nerve fibers and typically presents with pallor of the optic disc, which is distinct from pigmentary changes in the retina.

Question 499: A 45-year-old diabetic presents with sudden painless vision loss. Cotton wool spots and dot hemorrhages seen. HbA1c is 9.2. Most likely diagnosis?

A. Hypertensive retinopathy
B. CRAO
C. Diabetic retinopathy (Correct Answer)
D. CRVO

Explanation: ***Diabetic retinopathy*** - The presence of **cotton wool spots** and **dot hemorrhages** in a diabetic patient with poor glycemic control (HbA1c 9.2) are classic signs of **diabetic retinopathy**. - **Painless vision loss** is a common presentation, especially with macular edema or proliferative disease. *Hypertensive retinopathy* - While cotton wool spots can be seen, **dot hemorrhages are less characteristic** than flame-shaped hemorrhages. - The primary driver here is **diabetes** and poor glycemic control, not necessarily hypertension as the main cause. *CRAO* - **Central retinal artery occlusion** typically presents with **sudden, profound, painless monocular vision loss**. - Funduscopic examination would reveal a **cherry-red spot** and **pale retina**, not cotton wool spots and dot hemorrhages. *CRVO* - **Central retinal vein occlusion** is characterized by **extensive retinal hemorrhages** (often described as "blood and thunder" appearance), tortuous veins, and optic disc edema. - While it can cause painless vision loss and some hemorrhages, the specific combination of **cotton wool spots and dot hemorrhages** in a diabetic context points more strongly to diabetic retinopathy.

Question 500: True about hydroxychloroquine retinopathy EXCEPT:

A. Reversible on stopping drug (Correct Answer)
B. Cumulative dose dependent
C. Bull's eye maculopathy
D. Regular screening needed

Explanation: ***Reversible on stopping drug*** - **Hydroxychloroquine retinopathy** is generally **irreversible**, even after discontinuing the drug, and can progress after cessation. - The damage to the **retinal pigment epithelium** and photoreceptors is permanent, leading to irreversible vision loss. *Cumulative dose dependent* - The risk of hydroxychloroquine retinopathy is strongly associated with the **cumulative dose** and duration of treatment. - This underscores the importance of monitoring total dosage over time to assess risk. *Bull's eye maculopathy* - **Bull's eye maculopathy** is a classic and late-stage ophthalmoscopic finding in hydroxychloroquine retinopathy. - It involves a ring of **retinal pigment epithelium atrophy** surrounding an intact fovea. *Regular screening needed* - Due to the potential for irreversible vision loss and the cumulative dose-dependent risk, **regular ophthalmic screening** is crucial for patients on hydroxychloroquine. - Screening typically includes visual field testing, **spectral-domain optical coherence tomography (SD-OCT)**, and fundus autofluorescence.

Practice by Chapter

Retinal Anatomy and Physiology

Practice Questions

Age-Related Macular Degeneration

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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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