Diseases of the Retina

Diseases of the Retina Indian Medical PG Question 1: Retinopathy is most likely to be seen with which of the following conditions?

• A. Gestational diabetes
• B. Juvenile diabetes started before puberty
• C. Type 2 diabetes of 8 years duration (Correct Answer)
• D. Type 1 diabetes of 5 years duration

Diseases of the Retina Explanation: **Type 2 diabetes of 8 years duration** - **Diabetic retinopathy** is a common microvascular complication of diabetes mellitus [1]. - The risk of retinopathy increases with the **duration of diabetes** and the **severity of hyperglycemia**, making an 8-year duration with type 2 diabetes a significant risk factor [1]. *Type 1 diabetes of 5 years duration* - While type 1 diabetes can cause retinopathy, a 5-year duration is generally considered relatively short for the development of significant retinopathy, especially in early stages. - The risk of retinopathy in **Type 1 diabetes** becomes more pronounced after 10-15 years, though it can occur earlier. *Gestational diabetes* - **Gestational diabetes** is a temporary condition occurring during pregnancy and does not typically lead to chronic complications like retinopathy. - Retinopathy is rare in gestational diabetes because the disease duration is short and usually resolves post-partum. *Juvenile diabetes started before puberty* - **Juvenile diabetes** is synonymous with Type 1 diabetes [2]. Although early onset of diabetes increases lifetime risk, the duration of diabetes is a more critical factor for retinopathy development. - Without a specified duration, it's less predictive than an established longer duration of Type 2 diabetes.

Diseases of the Retina Indian Medical PG Question 2: Anterior choroidal artery is a branch of which of the following arteries?

• A. Basilar artery
• B. Anterior cerebral artery
• C. Posterior cerebral artery
• D. Internal carotid artery (Correct Answer)

Diseases of the Retina Explanation: ***Correct: Internal carotid artery*** - The **anterior choroidal artery** is a direct branch of the **internal carotid artery**, specifically originating from its **supraclinoid segment**. - It supplies crucial structures such as the **choroid plexus of the lateral ventricle**, parts of the **hippocampus**, **amygdala**, and the **posterior limb of the internal capsule**. - This is a clinically important vessel, as occlusion can lead to significant neurological deficits. *Incorrect: Basilar artery* - The basilar artery is part of the **posterior circulation**, formed by the union of the vertebral arteries. - It gives rise to branches like the **pontine arteries**, **superior cerebellar arteries**, and **posterior cerebral arteries**, but not the anterior choroidal artery. *Incorrect: Anterior cerebral artery* - The anterior cerebral artery is a terminal branch of the **internal carotid artery**, but it primarily supplies the **medial surface of the frontal and parietal lobes**. - It does not give rise to the anterior choroidal artery; instead, the anterior choroidal artery branches off the internal carotid artery more **proximally**, before the terminal bifurcation. *Incorrect: Posterior cerebral artery* - The posterior cerebral artery is a terminal branch of the **basilar artery** and is part of the posterior circulation. - It supplies the **occipital lobe** and parts of the **temporal lobe**. - Its branches include **posterior choroidal arteries** (not anterior choroidal artery), which supply the choroid plexus of the third ventricle and lateral ventricles.

Diseases of the Retina Indian Medical PG Question 3: A 2-year-old child presents with unilateral leukocoria and poor vision. What is the most likely diagnosis?

• A. Congenital cataract
• B. Retinoblastoma (Correct Answer)
• C. Endophthalmitis
• D. Coats disease

Diseases of the Retina Explanation: ***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

Diseases of the Retina Indian Medical PG Question 4: A diabetic patient presents to you with visual acuity of 6/9 in one eye. Further investigations revealed preretinal hemorrhages with neovascularization at the optic disc. What is the next step in management?

• A. Focal laser photocoagulation
• B. Pan-retinal photocoagulation (Correct Answer)
• C. Grid laser photocoagulation
• D. Scleral buckling

Diseases of the Retina Explanation: ***Pan-retinal photocoagulation*** - The presence of **preretinal hemorrhages** and **neovascularization at the optic disc (NVD)** indicates **high-risk proliferative diabetic retinopathy (PDR)**. - **NVD is a high-risk characteristic** for severe vision loss and requires urgent treatment with **pan-retinal photocoagulation (PRP)**. - PRP aims to ablate ischemic peripheral retina, which reduces the production of **VEGF** and other angiogenic factors that stimulate neovascularization. *Focal laser photocoagulation* - This treatment targets discrete leaking microaneurysms in cases of **clinically significant macular edema (CSME)**, which is not the primary issue here. - It is used for **non-proliferative diabetic retinopathy** with macular involvement, not for neovascularization. *Grid laser photocoagulation* - Grid laser is a type of focal laser used for **diffuse macular edema** where specific leaking microaneurysms cannot be identified. - It is not indicated for **neovascularization** or **preretinal hemorrhages**, which are signs of PDR. *Scleral buckling* - **Scleral buckling** is a surgical procedure primarily used to treat **retinal detachment** by indenting the sclera to relieve vitreoretinal traction. - It is not the initial or primary treatment for **proliferative diabetic retinopathy** or **neovascularization**.

Diseases of the Retina Indian Medical PG Question 5: All of the following take part in the blood supply of the optic chiasm except:

• A. Anterior cerebral artery
• B. Middle cerebral artery (Correct Answer)
• C. Anterior communicating artery
• D. Internal carotid artery

Diseases of the Retina Explanation: ***Middle cerebral artery*** - The **middle cerebral artery (MCA)** primarily supplies the lateral surface of the cerebral hemispheres, including portions of the frontal, parietal, and temporal lobes, but does not typically contribute to the direct blood supply of the **optic chiasm** [2]. - Its branches are more directed towards the **sylvian fissure** and cortical structures, rather than the deep midline structures like the optic chiasm [2]. *Anterior cerebral artery* - The **anterior cerebral artery (ACA)**, through its branches, including the **anterior communicating artery**, helps supply the anterior part of the optic chiasm [3]. - It forms part of the **Circle of Willis**, from which small perforating arteries can arise to supply deep brain structures [1]. *Anterior communicating artery* - The **anterior communicating artery (AComA)** connects the two anterior cerebral arteries and gives rise to small branches that directly contribute to the vascular supply of the **optic chiasm** [3]. - These branches are crucial for maintaining blood flow to this critical visual pathway structure. *Internal carotid artery* - The **internal carotid artery (ICA)** gives rise to the **ophthalmic artery** and the **anterior cerebral artery**, both of which contribute to the blood supply of the optic chiasm [3]. - Perforating branches from the ICA itself, particularly its terminal portion before bifurcating, can also directly supply the optic chiasm [3].

Diseases of the Retina Indian Medical PG Question 6: What is the approximate number of cones in the human retina?

• A. Approximately 3-5 million cones (Correct Answer)
• B. Approximately 25-50 million cones
• C. Approximately 50-100 million cones
• D. Approximately 10-20 million cones

Diseases of the Retina Explanation: Approximately 3-5 million cones - The human retina contains roughly **4.5 million cones**, concentrated in the **fovea**, which is responsible for **high-acuity vision** and color perception [1]. - Cones are light-sensitive cells that detect **fine details** and are essential for vision in **bright light conditions** [1]. *Approximately 10-20 million cones* - This range is significantly higher than the actual number of cones found in the human retina. - While there are millions of photoreceptors, the *majority are rods*, not cones [1]. *Approximately 25-50 million cones* - This figure vastly *overestimates* the number of cones in the human eye. - The total number of photoreceptor cells (rods and cones combined) in the retina typically ranges from **100-125 million** [1]. *Approximately 50-100 million cones* - This range is incorrect as it refers more closely to the *total number of rods* in the human retina, which is about **90-120 million** [1]. - Cones constitute a much smaller proportion of the total photoreceptor population [1].

Diseases of the Retina Indian Medical PG Question 7: Under the WHO "Vision 2020" program, the "SAFE" strategy is adopted for which of the following diseases:

• A. Glaucoma
• B. Onchocerciasis
• C. Trachoma (Correct Answer)
• D. Diabetic retinopathy

Diseases of the Retina Explanation: ***Trachoma*** * The SAFE strategy is an acronym for **Surgery** for trichiasis, **Antibiotics** to treat infection (especially azithromycin), **Facial cleanliness**, and **Environmental improvement** to prevent transmission. * This comprehensive approach is central to the global elimination efforts for **trachoma**, as outlined by the WHO's Vision 2020 initiative. *Glaucoma* * Glaucoma management typically involves **medications (eye drops)** to lower intraocular pressure, laser therapy, or **surgery** to improve fluid drainage from the eye. * The SAFE strategy with its specific components (Surgery for trichiasis, Antibiotics, Facial cleanliness, Environmental improvement) is not applicable to the pathophysiology or treatment of **glaucoma**. *Onchocerciasis* * Onchocerciasis, or **river blindness**, is primarily controlled through mass drug administration of **ivermectin** to kill microfilariae and prevent new infections. * While both are Neglected Tropical Diseases causing blindness, the SAFE strategy is not designed for **onchocerciasis** prevention or treatment, which focuses on vector control and anthelmintic drugs. *Diabetic retinopathy* * Management of diabetic retinopathy focuses on **strict glycemic control**, managing blood pressure and lipids, and interventions such as **laser photocoagulation**, intravitreal injections of anti-VEGF agents, or vitrectomy for severe cases. * The term "SAFE strategy" with its specific interventions relates to bacterial infection control and environmental hygiene, which are not primary methods for managing **diabetic retinopathy**.

Diseases of the Retina Indian Medical PG Question 8: All are ophthalmological emergencies except -

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

Diseases of the Retina 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.

Diseases of the Retina Indian Medical PG Question 9: A person is not able to count fingers from a distance of 6 meters. He shall be categorized into which type of blindness?

• A. Moderate visual impairment
• B. Severe visual impairment (Correct Answer)
• C. Near-total blindness
• D. Profound visual impairment

Diseases of the Retina Explanation: ***Severe visual impairment*** - Severe visual impairment is defined as visual acuity **less than 6/60 to 3/60** (presenting visual acuity). - The key clinical threshold is the **inability to count fingers at 6 meters**, which corresponds to VA < 6/60. - This category represents a significant functional vision loss where the person can typically still count fingers at 3 meters but not at 6 meters. - According to **WHO ICD-10 classification**, this falls under **Category H1** (severe visual impairment). *Moderate visual impairment* - Moderate visual impairment is characterized by visual acuity of **less than 6/18 to 6/60**. - A person with moderate visual impairment would **still be able to count fingers at 6 meters**. - This does not match the clinical presentation described in the question. *Profound visual impairment* - Profound visual impairment (also called **Blindness Category 1**) is defined as visual acuity **less than 3/60 to 1/60**. - The key threshold here is the **inability to count fingers at 3 meters** (but can count at 1 meter). - This is more severe than what is described in the question, as the question only specifies inability at 6 meters. *Near-total blindness* - Near-total blindness (**Blindness Category 2**) refers to visual acuity **less than 1/60 to light perception only**. - This represents the ability to perceive hand movements close to the face or only light perception. - This is far more severe than the presentation described in the question.

Diseases of the Retina Indian Medical PG Question 10: Treatment of choice for clinically significant macular edema in a diabetic is?

• A. Intravitreal anti-VEGF injections (Correct Answer)
• B. Control of Diabetes
• C. Panretinal Photocoagulation
• D. Focal Photocoagulation

Diseases of the Retina Explanation: ***Intravitreal anti-VEGF injections*** - **Anti-VEGF agents** (e.g., ranibizumab, aflibercept) are the first-line treatment for **clinically significant diabetic macular edema (DME)** as they effectively reduce vascular leakage and improve vision. - They target **vascular endothelial growth factor (VEGF)**, a key mediator of increased vascular permeability and neovascularization in diabetic retinopathy. *Control of Diabetes* - While essential for preventing the **progression of diabetic retinopathy** and overall health, it is not the primary direct treatment for *existing* clinically significant macular edema. - Good glycemic control can reduce the *risk* of developing DME but does not acutely resolve established edema. *Panretinal Photocoagulation* - **Panretinal photocoagulation (PRP)** is primarily used for **proliferative diabetic retinopathy (PDR)** to ablate ischemic retina and reduce neovascularization. - It is not the treatment of choice for macular edema, as it can sometimes worsen macular function and visual acuity due to treatment-induced damage. *Focal Photocoagulation* - **Focal laser photocoagulation** was historically used for DME, targeting discrete leaking microaneurysms. - While effective for specific focal leakage, it has largely been superseded by **anti-VEGF injections** due to their superior efficacy in diffuse edema and better visual outcomes, especially when edema involves the fovea.

Diseases of the Retina Flashcard 1 of 10

Question: Treatment of cystoid macular edema (CME) consists of instillation of intravitreal _____ or anti-VEGF agents; or use of operative therapy like macular grid laser

Answer: steroids

Diseases of the Retina Flashcard 2 of 10

Question: _____ is the second most common retinal vascular disorder after diabetic retinopathy.

Answer: Retinal vein occlusion (RVO)

Diseases of the Retina Flashcard 3 of 10

Question: _____ is characterized by drusen, which is deposition of yellowish extracellular material in between Bruch's membrane and the retinal pigment epithelium

Answer: Dry macular degeneration

Diseases of the Retina Flashcard 4 of 10

Question: _____ is the most common hereditary fundus dystrophy

Answer: Retinitis pigmentosa

Diseases of the Retina Flashcard 5 of 10

Question: In _____ phase of FFA, there is complete filling of retinal arterioles and capillaries followed by laminar filling of veins

Answer: arteriovenous

Diseases of the Retina Flashcard 6 of 10

Question: _____ is useful in the measurement of retinal thickening, thus allowing the assessment of the therapeutic response in cystoid macular edema

Answer: OCT

Diseases of the Retina Flashcard 7 of 10

Question: _____ is the most common macular dystrophy.

Answer: Stargardt disease

Diseases of the Retina Flashcard 8 of 10

Question: In gyrate atrophy, retinal pigment epithelial (RPE) degeneration begins in the _____ and is characterized by scalloped areas of RPE loss, with eventual loss of medium-sized choroidal vessels.

Answer: periphery

Diseases of the Retina Flashcard 9 of 10

Question: "Splashed sauce" appearance on ophthalmoscopy is seen in _____

Answer: CRVO

Diseases of the Retina Flashcard 10 of 10

Question: _____ is the spontaneous serous detachment of neurosensory retina in the macular region.

Answer: Central serous retinopathy