This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vascular Disorders, Subject name: Ophthalmology
Cherry red spot in retina is a feature of: 
Select and explain. 
A. Infantile Gaucher's disease, B. Niemann Pick disease, C. Fabry's disease, D. CRVO
B: Niemann Pick disease
Answer: B: Niemann Pick disease 
Explanation: Ans: B (Niemann Pick disease) Ref: Kanski 7th edition Clinical ophthalmology,, pg no 683-684Explanation:Causes of cherry red spot:Central retinal artery occlusionBlunt injury - Berlin's edeme or commotion retinaeQuinine toxicityMacular holeGangliosidosisMucolipidosisTay Sachs diseaseSandhoff diseaseNiemann Pick diseaseFaber diseaseMechanism of Cherry red spotThe fovea is the thinnest part of the retina & is devoid of ganglion cell layer.The following mechanisms causes cherry red spotWhen the retina becomes opaque due to edema (CRAO)Injury to the photoreceptors (Commotion retina)Due to intracellular accumulation of glvcolipids & phospholipids in the ganglion cellThe fovea remains transparent & transmits the underlying choroid.This appears as cherry red spot.