Diseases of the Retina Practice Questions

Q: A 2-year-old child presents with unilateral leukocoria and poor vision. What is the most likely diagnosis?

Retinoblastoma. ***Retinoblastoma*** - **Leukocoria** (white pupillary reflex) is the **most common presenting sign** of retinoblastoma, occurring in approximately 60% of cases - The combination of **unilateral leukocoria** and **poor vision** in a **2-year-old child** (peak age 18-24 months) is highly suggestive - It is a **rapidly growing malignant intraocular tumor** arising from the neural retina, requiring urgent evaluation and treatment - Other presenting features may include **strabismus**, **red eye**, and in advanced cases, **proptosis** *Congenital cataract* - Can also present with **leukocoria** due to opacification of the lens - However, congenital cataracts are typically **bilateral** (75% of cases) and diagnosed earlier in infancy - The **static, non-progressive nature** distinguishes it from the rapidly growing retinoblastoma - Family history and associated systemic conditions (TORCH infections, metabolic disorders) are common *Endophthalmitis* - Severe **intraocular infection** affecting vitreous and aqueous humor - Typically presents with **acute pain**, **severe redness**, **hypopyon**, and **rapid vision loss** - Usually follows **penetrating trauma** or **intraocular surgery**, which would be uncommon in a 2-year-old - **Leukocoria without acute inflammatory signs** makes this diagnosis unlikely *Coats disease* - Characterized by **abnormal telangiectatic retinal vessels** with **exudative retinal detachment** and **yellow subretinal exudates** - Can present with leukocoria (yellow reflex due to lipid deposits) in young children - However, it typically affects **older children** (mean age 5-8 years), is predominantly **unilateral**, and has a **more indolent course** - More common in **males** and usually lacks the rapid progression of retinoblastoma

Q: Which of the following features is characteristic of familial retinoblastoma?

Bilateral occurrence. ***Bilateral occurrence*** - Familial retinoblastoma is characterized by **bilateral involvement** of the eyes in approximately 60-70% of cases, as the inherited germline mutation in the **RB1 gene** predisposes both retinas. - The presence of the germline mutation means that every cell in the body carries the predisposition, increasing the likelihood of multiple primary tumor events, often in both eyes. - **Bilaterality** is the key **clinical characteristic** that distinguishes familial from sporadic retinoblastoma (which is typically unilateral). *Autosomal recessive inheritance* - Retinoblastoma, including familial forms, typically follows an **autosomal dominant inheritance pattern** with incomplete penetrance (~90%), not autosomal recessive. - A single mutated copy of the **RB1 gene** inherited from a parent is sufficient to predispose individuals to the disease. *Mutation in the RB gene* - While **germline mutation in the RB1 gene** is indeed present in familial retinoblastoma (and somatic mutations occur in sporadic forms), the question asks for a *characteristic feature* that distinguishes familial from sporadic forms. - Both familial and sporadic retinoblastoma involve RB1 gene dysfunction, but the **clinical presentation** (bilateral vs. unilateral), **age of onset** (earlier in familial), and **heritability** are the distinguishing features, not simply the presence of an RB1 mutation. - The hallmark clinical characteristic is **bilaterality**, not just the genetic mutation. *Higher incidence than sporadic retinoblastoma* - Familial retinoblastoma accounts for only a **smaller proportion** (about 25-40%) of all retinoblastoma cases. - **Sporadic retinoblastoma** (non-heritable, de novo somatic mutation) is actually more common, comprising 60-75% of all cases.

Q: All of the following cause panuveitis except?

Ankylosing spondylitis. ***Ankylosing spondylitis*** - This condition primarily causes **acute anterior uveitis**, affecting the front part of the eye, not typically the entire uveal tract (**panuveitis**). - Its association with uveitis is usually **unilateral** and presents with symptoms like pain, redness, and photophobia. *Sarcoidosis* - **Sarcoidosis** is a systemic inflammatory disease that can lead to **granulomatous panuveitis**, affecting the anterior, intermediate, and posterior segments of the eye. - Ocular involvement in sarcoidosis can manifest as choroiditis, retinitis, and vitritis, indicative of widespread inflammation. *Sympathetic ophthalmitis* - This is a rare, bilateral, **granulomatous panuveitis** that occurs after a penetrating ocular injury or surgery to one eye. - It involves inflammation of the entire uveal tract in both the injured and the fellow, uninjured eye. *Toxoplasmosis* - **Toxoplasmosis** often causes a focal **retinochoroiditis** which can spread to involve the vitreous and anterior chamber, leading to a form of **panuveitis**. - The inflammatory response is primarily to the parasitic infection, manifesting as a necrotizing retinitis with significant surrounding inflammation.

Q: Mizuo's phenomenon is seen in:

Oguchi's disease. ***Oguchi's disease*** - **Mizuo's phenomenon** is a characteristic feature of **Oguchi's disease**, an **autosomal recessive** form of congenital stationary night blindness. - It involves the unusual finding of a **golden-yellowish or grayish discoloration of the fundus** in the light-adapted state, which disappears after prolonged dark adaptation. *Fundus albipunctatus* - This condition is characterized by **numerous small, discrete white or yellow-white flecks** scattered diffusely across the fundus. - While it is also a form of congenital stationary night blindness, it does not exhibit the **Mizuo's phenomenon**. *Fundus flavimaculatus* - This term is often used interchangeably with **Stargardt's disease**, which is a **macular dystrophy** characterized by progressive vision loss and yellow flecks around the macula. - This condition does not involve **Mizuo's phenomenon** or night blindness of the static type. *Choroideremia* - This is an **X-linked recessive** progressive chorioretinal degeneration primarily affecting males, leading to severe vision loss and night blindness due to loss of the **choroid**, **retinal pigment epithelium**, and **photoreceptors**. - It is a degenerative condition and does not present with the reversible fundus discoloration seen in **Mizuo's phenomenon**.

Q: A cherry red spot is found in which of the following conditions?

Tay-Sach's disease. ***Tay-Sach's disease*** - The **cherry-red spot** in Tay-Sachs disease is due to the accumulation of **GM2 gangliosides** in the retinal ganglion cells, making the fovea appear red due to the normal choroidal vasculature. - This is a classic finding in **infantile Tay-Sachs disease**, a lysosomal storage disorder caused by a deficiency of the **hexosaminidase A enzyme**. *Gangliosidosis* - While GM1 gangliosidosis can rarely present with a cherry-red spot, it is more commonly associated with **coarse facial features**, hepatosplenomegaly, and skeletal abnormalities. - The **enzyme deficiency** in GM1 gangliosidosis is **beta-galactosidase**, differing from Tay-Sachs disease. *Retinopathy of prematurity* - This condition involves **abnormal blood vessel growth in the retina** of premature infants, often leading to retinal detachment and vision loss. - It does not typically present with a **cherry-red spot**; rather, it is characterized by areas of vascularized and avascular retina. *Gaucher's disease* - Gaucher's disease is characterized by the accumulation of **glucocerebroside** in macrophages, leading to hepatosplenomegaly, bone pain, and neurological symptoms in some types. - A **cherry-red spot** is not a typical ocular finding in Gaucher's disease; **strabismus** and **oculomotor apraxia** are more common.

Q: Fluorescein dye for ophthalmological diagnosis is injected into:

Antecubital vein. ***Antecubital vein*** - Fluorescein angiography requires rapid delivery of the dye into the **systemic circulation** for quick visualization of retinal and choroidal vasculature. - The **antecubital vein** is a readily accessible, large superficial vein that allows for quick and efficient intravenous dye injection. *Popliteal vein* - The popliteal vein is located behind the **knee** and is not a standard or practical site for routine intravenous injections, especially when rapid delivery to the eye is needed. - Its location makes it less accessible and potentially more uncomfortable for the patient compared to an arm vein. *Femoral vein* - The femoral vein is a large, deep vein in the **groin**, typically reserved for central venous access or specific procedures due to the increased risk of complications like infection or hematoma. - It is not routinely used for peripheral intravenous injections such as fluorescein, where a more superficial and accessible vein is preferred. *Subclavian vein* - The subclavian vein is a **central vein** located under the clavicle, accessed via a more invasive procedure, usually for central venous catheters or hemodialysis access. - It carries higher risks compared to peripheral venipuncture and is not chosen for simple diagnostic dye injections like fluorescein.

Q: What is the best diagnostic test for Best's disease?

EOG. ***EOG*** - The **electro-oculogram (EOG)** measures the potential difference between the cornea and Bruch's membrane, which is severely abnormal in **Best's disease**. - A characteristic feature is a **reduced Arden ratio (Light Peak/Dark Trough)**, typically below 1.5, even in asymptomatic carriers. *Dark adaptation* - This test assesses the eye's ability to adapt to low light conditions, primarily indicative of **rod photoreceptor function**. - While visual disturbances can occur in Best's disease, dark adaptation is not the primary diagnostic test and might be normal or mildly affected. *ERG* - The **electroretinogram (ERG)** measures the electrical responses of the **photoreceptors and inner retinal cells** to light stimuli. - In Best's disease, the ERG is typically **normal**, as the primary pathology affects the RPE and not directly the photoreceptors (initially). *Gonioscopy* - **Gonioscopy** is an examination technique used to visualize the **anterior chamber angle** of the eye, mainly for diagnosing and managing **glaucoma**. - It is unrelated to Best's disease, which is a **macular dystrophy** affecting the retina and RPE.

Q: Which of the following conditions is NOT associated with retinitis pigmentosa?

Marfan's Syndrome. ***Marfan's Syndrome*** - Marfan's Syndrome is primarily a **connective tissue disorder** affecting the **cardiovascular system**, **skeletal system**, and **eyes** (e.g., lens dislocation). - It is **not directly associated** with the progressive **photoreceptor degeneration** characteristic of retinitis pigmentosa. *Usher Syndrome* - Usher Syndrome is a **recessive genetic disorder** characterized by **hearing loss** and progressive **vision loss** due to retinitis pigmentosa. - It involves both **auditory** and **visual impairments**, directly linking it to retinitis pigmentosa. *Kearns-Sayre Syndrome* - Kearns-Sayre Syndrome is a **mitochondrial disorder** that includes **external ophthalmoplegia**, **cardiac conduction defects**, and often **pigmentary retinopathy** resembling retinitis pigmentosa. - The retinal degeneration in Kearns-Sayre syndrome is a **hallmark ocular manifestation**. *Bassen-Kornzweig Syndrome* - Also known as **abetalipoproteinemia**, this is a rare **autosomal recessive disorder** characterized by the inability to absorb **dietary fats and fat-soluble vitamins** (especially vitamin A). - Severe **vitamin A deficiency** can lead to atypical retinitis pigmentosa-like retinal degeneration and **night blindness**.

Question 1

A 2-year-old child presents with unilateral leukocoria and poor vision. What is the most likely diagnosis?

Accepted Answer

Retinoblastoma

Answer

Congenital cataract

Answer

Endophthalmitis

Answer

Coats disease

Question 2

Which of the following features is characteristic of familial retinoblastoma?

Accepted Answer

Bilateral occurrence

Answer

Autosomal recessive inheritance

Answer

Mutation in the RB gene

Answer

Higher incidence than sporadic retinoblastoma

Question 3

All of the following cause panuveitis except?

Accepted Answer

Ankylosing spondylitis

Answer

Sarcoidosis

Answer

Sympathetic ophthalmitis

Answer

Toxoplasmosis

Question 4

Mizuo's phenomenon is seen in:

Accepted Answer

Oguchi's disease

Answer

Fundus albipunctatus

Answer

Fundus flavimaculatus

Answer

Choroideremia

Question 5

A cherry red spot is found in which of the following conditions?

Accepted Answer

Tay-Sach's disease

Answer

GM1 gangliosidosis

Answer

Retinopathy of prematurity

Answer

Gaucher's disease

Question 6

Fluorescein dye for ophthalmological diagnosis is injected into:

Accepted Answer

Antecubital vein

Answer

Popliteal vein

Answer

Femoral vein

Answer

Subclavian vein

Question 7

What is the best diagnostic test for Best's disease?

Accepted Answer

EOG

Answer

Dark adaptation

Answer

ERG

Answer

Gonioscopy

Question 8

Which of the following conditions is NOT associated with retinitis pigmentosa?

Accepted Answer

Marfan's Syndrome

Answer

Kearns-Sayre Syndrome

Answer

Usher Syndrome

Answer

Bassen-Kornzweig Syndrome

Diseases of the Retina — MCQs

Diseases of the Retina — MCQs

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