Diseases of the Retina Practice Questions

Q: What is the cause of glaucoma in retinoblastoma?

Neovascularisation. ***Neovascularisation*** - Retinoblastoma leads to **neovascularization of the iris (NVI)** and **angle structures** due to tumor necrosis, ischemia, and release of **angiogenic factors (VEGF)**. - The **neovascular membrane** grows over and obstructs the **trabecular meshwork** and anterior chamber angle, causing **secondary neovascular glaucoma**. - This is the **most characteristic and common mechanism** of glaucoma in advanced retinoblastoma. - Neovascular glaucoma in retinoblastoma is typically **refractory to medical treatment** and indicates poor prognosis. *Blockage of trabecular network* - While tumor cells can directly seed into the anterior chamber and block the trabecular meshwork, this mechanism is **less common** than neovascularization. - This option is also **less specific** as it doesn't identify the underlying pathophysiological process (neovascularization) that is characteristic of retinoblastoma-associated glaucoma. - Direct trabecular blockage by tumor cells typically occurs in advanced disease and often coexists with neovascularization. *Mass effect of the tumour* - The tumor mass itself rarely causes glaucoma through direct mechanical compression of outflow pathways. - Retinoblastoma causes glaucoma primarily through **secondary mechanisms** such as inflammation, neovascularization, or cellular seeding, not simple bulk effect. - Massive tumors may cause angle closure, but this is uncommon compared to neovascular mechanisms. *Lysis of the lens* - **Phacolytic glaucoma** from lens protein leakage is rare in retinoblastoma. - While lens damage can occur with advanced tumors, it is **not a typical or characteristic cause** of glaucoma in retinoblastoma. - The primary mechanisms involve the **tumor-angle-trabecular meshwork axis**, not lens pathology.

Q: Which cells in the retina are primarily affected by methanol toxicity?

Ganglion cells of the retina. ***Ganglion cells of the retina*** - Methanol toxicity, specifically its metabolite **formic acid**, selectively targets and damages **retinal ganglion cells**. - This damage leads to **optic neuropathy** and can cause permanent vision loss or blindness. *Photoreceptor cells* - These cells (rods and cones) are responsible for light detection but are generally **not primarily affected** by methanol toxicity. - While severe toxicity can lead to widespread retinal damage, initial and primary damage is to the ganglion cells. *Bipolar cells* - Bipolar cells transmit signals from photoreceptors to ganglion cells but are **not the primary target** of methanol's toxic effects. - Their damage would typically be secondary to severe, prolonged methanol poisoning. *Horizontal cells* - Horizontal cells are involved in lateral inhibition and signal processing within the retina but are **not selectively vulnerable** to methanol toxicity. - Damage to these cells is not a defining feature of methanol-induced vision loss.

Q: All of the following are true for retinopathy of prematurity except which of the following?

End result is bilateral blindness. ***End result is bilateral blindness*** - While retinopathy of prematurity (ROP) can lead to severe vision loss or blindness, it is not always a bilateral end result, especially with early diagnosis and treatment. The severity can vary between eyes, and some cases resolve spontaneously. - Modern screening and intervention strategies, such as laser photocoagulation or anti-VEGF injections, are often successful in preventing complete blindness in one or both eyes. *Due to hypoxia there occurs neovascularization followed by fibroproliferation* - This statement accurately describes the pathogenesis of ROP. The initial phase involves delayed normal retinal vascularization, followed by a proliferative phase characterized by **neovascularization** in response to hypoxia in the avascular retina. - These new, abnormal vessels are fragile and prone to bleeding, and their associated **fibrovascular proliferation** can lead to retinal detachment. *Blindness can be prevented by early diagnosis and ablation of vascular premature retina with cryotherapy or photocoagulation* - This is a true statement. **Early diagnosis** through ophthalmologic screening of premature infants is crucial, and treatments like **laser photocoagulation** or **cryotherapy** are effective in ablating the avascular peripheral retina to halt the progression of abnormal vessel growth. - These interventions reduce the hypoxic drive that fuels neovascularization, thereby preventing severe retinal detachment and subsequent blindness. *Occurs in premature infants due to abnormal retinal blood vessel development.* - This statement is correct. ROP is a disease primarily affecting **premature infants** because their retinal blood vessels have not completed development by the time of birth. - Postnatal factors, including oxygen fluctuations and low birth weight, further disrupt this critical development, leading to **abnormal vascularization**.

Q: Fluorescein angiography is used to examine -

Retinal vasculature. ***Retinal vasculature*** - **Fluorescein angiography** involves injecting fluorescein dye into a vein and taking rapid photographs of the retina as the dye perfuses, allowing for detailed visualization of the **retinal blood vessels**. - This technique is crucial for diagnosing and monitoring conditions like **diabetic retinopathy**, **macular degeneration**, and **retinal vascular occlusions** by identifying leaks, non-perfusion areas, and abnormal vessel growth. *Ciliary vasculature* - The **ciliary body vasculature** is not directly visualized by standard fluorescein angiography as it is located anterior to the retina within the uveal tract. - While some dye may perfuse the ciliary body, the primary imaging target and diagnostic utility of fluorescein angiography are the **retinal and choroidal circulations**. *Corneal vasculature* - The normal **cornea is avascular**, meaning it does not contain blood vessels. - **Corneal neovascularization** (new vessel growth) can occur due to pathology, but fluorescein angiography is not the primary or most suitable technique for assessing corneal vessels, which are more readily visible with slit-lamp biomicroscopy. *Conjunctival vasculature* - The **conjunctiva** contains numerous small vessels, but these are superficial and can be directly observed with a slit lamp or even the naked eye. - Fluorescein angiography is an invasive procedure with a higher spatial resolution designed for deeper, more intricate vascular networks like those in the retina, making it overkill and inappropriate for routine assessment of the **conjunctival vasculature**.

Q: Which of the following conditions is NOT diagnosed by fluorescein angiography?

Hypertensive retinopathy. ***Hypertensive retinopathy*** - This condition is primarily diagnosed by **clinical fundoscopic examination**, not fluorescein angiography - Diagnosis is based on characteristic clinical findings: **arteriovenous nicking, copper/silver wire arterioles, cotton-wool spots, flame-shaped hemorrhages, and papilledema** in severe cases - **Fluorescein angiography** is rarely needed and only used in research settings or to assess severe complications; it is **not a standard diagnostic tool** for hypertensive retinopathy *Diabetic retinopathy* - **Fluorescein angiography** is extensively used for diagnosing and staging diabetic retinopathy - It helps identify **microaneurysms, capillary non-perfusion areas, macular edema, and neovascularization** - Essential for detecting **proliferative diabetic retinopathy** and planning laser photocoagulation *Central serous retinopathy* - **Fluorescein angiography** shows characteristic **"smokestack" or "inkblot" pattern** of leakage at the RPE level - Demonstrates one or more **leakage points** with progressive pooling of dye in the subretinal space - While **OCT** is now preferred for initial diagnosis, FA remains valuable for identifying leakage sites and guiding treatment *Choroidal neovascularization* - **Fluorescein angiography** is the gold standard for diagnosing **choroidal neovascularization (CNV)** - Shows **early hyperfluorescence with progressive leakage** from abnormal vessels - Critical for determining the **type (classic vs occult), location, and extent** of CNV for treatment planning

Q: Choroidal neovascularization is most commonly seen in which of the following refractive errors?

Myopia. ***Myopia*** - High myopia, particularly **pathologic myopia** (>6D or axial length >26mm), is a significant risk factor for **choroidal neovascularization (CNV)** among refractive errors due to the elongation of the eyeball stretching and thinning the choroid and Bruch's membrane. - The mechanical stress and associated **degenerative changes** in the posterior segment can lead to ruptures in Bruch's membrane, facilitating the growth of new, fragile blood vessels from the choroid into the subretinal space. - **Pathologic myopia** is the **second most common cause of CNV overall** (after age-related macular degeneration) and the **most common cause in patients under 50 years**. *Hypermetropia* - Hypermetropia (farsightedness) is associated with a **shorter axial length** of the eye, which generally reduces the risk of the structural changes that predispose to CNV. - While other conditions can cause CNV, hypermetropia itself is **not a risk factor** for its development. *Presbyopia* - Presbyopia is an **age-related loss of accommodation** due to hardening of the lens and weakening of the ciliary muscle, affecting near vision. - It is a refractive change related to the lens's flexibility and **not directly to the structural changes** in the choroid or retina that lead to CNV. *Astigmatism* - Astigmatism is a refractive error where the eye's cornea or lens has **irregular curvature**, causing blurred vision at all distances. - It is a **surface curvature issue** and does not typically involve the deep structural changes in the choroid or retina that are conducive to choroidal neovascularization.

Q: What condition is characterized by an "umbrella" configuration on fluorescein angiography?

Central serous retinopathy. ***Central serous retinopathy*** - The "umbrella" or "smokestack" configuration on **fluorescein angiography** is a classic finding in central serous retinopathy, indicating leakage of dye creating a mushroom-shaped plume. - This leakage originates from the **retinal pigment epithelium (RPE)** into the subretinal space, causing serous detachment of the neurosensory retina. *Retinitis pigmentosa* - Characterized by **progressive photoreceptor degeneration** and **pigmentary changes** in the retina, often described as "bone-spicule" pigmentation. - Fluorescein angiography in retinitis pigmentosa typically shows **atrophy** and **window defects**, not an umbrella pattern of leakage. *Rhegmatogenous retinal detachment* - Involves a **full-thickness break in the retina** that allows vitreous fluid to pass into the subretinal space, causing the retina to detach. - Fluorescein angiography is generally not used for primary diagnosis and would not show an umbrella pattern, but rather **non-perfusion** or vascular changes in the detached area. *Eale's disease* - A rare **idiopathic obliterative periphlebitis** primarily affecting the retinal veins, leading to recurrent vitreous hemorrhages and retinal neovascularization. - Fluorescein angiography would reveal **vascular sheathing**, **non-perfusion**, and **neovascularization**, which are distinct from the umbrella configuration.

Q: Retinitis pigmentosa is characterized by ?

Loss of peripheral vision. ***Loss of peripheral vision*** - Retinitis pigmentosa is a group of genetic disorders that cause **progressive degeneration of photoreceptor cells**, primarily rods, which are concentrated in the periphery of the retina. - This degeneration leads to a gradual **loss of peripheral vision**, often beginning with **night blindness** and progressing to tunnel vision. *Loss of central vision* - Loss of central vision is characteristic of conditions affecting the **macula**, such as **age-related macular degeneration** or certain forms of **macular dystrophy**. - While later stages of retinitis pigmentosa can affect central vision, the initial and primary characteristic is loss of peripheral vision. *Tubular vision* - **Tubular vision** is an advanced stage of peripheral vision loss, where the visual field shrinks to a narrow central area, resembling looking through a tube. - While it can be a consequence of retinitis pigmentosa, it is a description of the **extent of visual field constriction** rather than the primary characteristic of the disease itself. *Visual field constriction* - **Visual field constriction** is a general term for any reduction in the extent of the visual field. - While retinitis pigmentosa certainly causes visual field constriction, the term "loss of peripheral vision" is more specific to the initial and dominant pattern of vision loss in this condition.

Q: Which of the following statements about the c-wave in electroretinogram (ERG) is most accurate?

The 'c' wave is a slow positive wave.. ***The 'c' wave is a slow positive wave.*** - The **c-wave** in an ERG is generated by the **retinal pigment epithelium (RPE)** and is characterized by its **slow, positive deflection**. - It reflects the **hyperpolarization** of the RPE cells in response to light stimulation. *The 'c' wave is a negative wave.* - This statement is incorrect because the **c-wave** is consistently observed as a **positive deflection** in the ERG tracing. - A negative wave like the **a-wave** is generated by photoreceptor hyperpolarization, which is a different component. *The 'b' wave arises primarily from photoreceptors.* - The **b-wave** primarily arises from the **Müller cells** and **bipolar cells**, not directly from photoreceptors. - Photoreceptor activity is primarily reflected in the **a-wave**. *The 'a' wave is a positive wave.* - The **a-wave** is a **negative deflection** in the ERG, representing the **hyperpolarization of photoreceptors** in response to light. - It is the earliest component of the ERG waveform.

Q: Commotio retinae affects which part of the retina -

Posterior pole. ***Posterior pole*** - **Commotio retinae**, also known as Berlin's edema, primarily affects the **posterior pole** of the retina, particularly the macula. - This condition results from **blunt trauma** to the globe, causing disruption of the outer retinal photoreceptors and retinal pigment epithelium, leading to retinal whitening in the area of impact. *Peripheral retina* - While blunt trauma can affect the peripheral retina, commotio retinae specifically refers to the **edematous whitening** that occurs more centrally. - Trauma to the periphery is more commonly associated with **retinal tears or detachments**, rather than the diffuse whitening seen in commotio retinae. *Inferior-nasal part* - This is a specific quadrant of the retina, but commotio retinae is not confined to or preferentially found in the **inferior-nasal part**. - The location of commotio retinae depends on the **point of impact** and the transmission of force, but symptoms are most prominent when the macula at the posterior pole is involved. *Superior-nasal part* - Similar to the inferior-nasal part, the **superior-nasal part** is a specific retinal quadrant. - Commotio retinae is a more generalized finding of retinal edema and whitening due to trauma, not consistently localized to this particular region, though it can occur if that area is directly impacted.

Question 1

What is the cause of glaucoma in retinoblastoma?

Accepted Answer

Neovascularisation

Answer

Mass effect of the tumour

Answer

Blockage of trabecular network

Answer

Lysis of the lens

Question 2

Which cells in the retina are primarily affected by methanol toxicity?

Accepted Answer

Ganglion cells of the retina

Answer

Photoreceptor cells

Answer

Bipolar cells

Answer

Horizontal cells

Question 3

All of the following are true for retinopathy of prematurity except which of the following?

Accepted Answer

End result is bilateral blindness

Answer

Due to hypoxia there occurs neovascularization followed by fibroproliferation

Answer

Occurs in premature infants due to abnormal retinal blood vessel development.

Answer

Blindness can be prevented by early diagnosis and ablation of avascular peripheral retina with cryotherapy or photocoagulation

Question 4

Fluorescein angiography is used to examine -

Accepted Answer

Retinal vasculature

Answer

Ciliary vasculature

Answer

Corneal vasculature

Answer

Conjunctival vasculature

Question 5

Which of the following conditions is NOT diagnosed by fluorescein angiography?

Accepted Answer

Hypertensive retinopathy

Answer

Diabetes retinopathy

Answer

Central serous retinopathy

Answer

Choroidal neovascularization

Question 6

Choroidal neovascularization is most commonly seen in which of the following refractive errors?

Accepted Answer

Myopia

Answer

Hypermetropia

Answer

Presbyopia

Answer

Astigmatism

Question 7

What condition is characterized by an "umbrella" configuration on fluorescein angiography?

Accepted Answer

Central serous retinopathy

Answer

Retinitis pigmentosa

Answer

Rhegmatogenous retinal detachment

Answer

Eale's disease

Question 8

Retinitis pigmentosa is characterized by ?

Accepted Answer

Loss of peripheral vision

Answer

Loss of central vision

Answer

Visual field constriction

Answer

Tubular vision

Question 9

Which of the following statements about the c-wave in electroretinogram (ERG) is most accurate?

Accepted Answer

The 'c' wave is a slow positive wave.

Answer

The 'c' wave is a negative wave.

Answer

The 'b' wave arises primarily from photoreceptors.

Answer

The 'a' wave is a positive wave.

Question 10

Commotio retinae affects which part of the retina -

Accepted Answer

Posterior pole

Answer

Peripheral retina

Answer

Inferior-nasal part

Answer

Superior-nasal part

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

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