This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Following are the causes of painless sudden onset of loss of vision except - \nSelect and explain. \nA. Acute congestive glaucoma, B. Vitreous hemorrhage, C. CRAO, D. Central serous retinopathy', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Acute congestive glaucoma o Acute congestive glaucoma causes sudden painful loss of vision.SuddenGradualPainfulPainlessPainfulPainlesso Acute congestive (angle closure) glaucomao Acute iridocyclitis (uveitis)o Chemical & mechanical injury to eyeballo Endophthalmitiso Optic neuritiso Macular edemao CRAO (central retinal artery' occlusion)o CRVO (central retinal vein occlusion)o Central serous retinopathyo Retinal detachmento Exudative Age-Related Macular Degeneration (ARMD)o Vitreous & retinal hemorrhageo Methyl alcohol amblyopiao Subluxation or dislocation of lenso Corneal ulcerationo Chronic simple glaucomao Chronic iridocyclitis (uveitis)o Progressive pterygiumo Corneal dystrophyo Comeal degenerationo Cataract (development & senile)o Chorioretinal degenerationo Dry type- Age-related macular degeneration (ARMD)o Diabetic retinopathyo Refractive errorso Presbyopia", 'role': 'assistant'}]