This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy, Development and clinical examination, Subject name: Ophthalmology
[{'content': 'Following are the causes of sudden loss of vision except \nSelect and explain. \nA. Angle closure glaucoma, B. Endophthalmitis, C. Central serous retinopathy, D. Corneal ulceration', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Sudden painless loss of vision \x01 Central retinal aery occlusion \x01 Massive vitreous hemorrhage \x01 Retinal detachment involving macular area \x01 Ischaemic central retinal vein occlusion The sudden painless onset of defective vision \x01 Central serous retinopathy \x01 Optic neuritis \x01 Methyl alcohol amblyopia \x01 Non-ischemic central retinal vein occlusion Sudden painful loss of vision \x01 Acute congestive glaucoma \x01 Acute iridocyclitis \x01 Chemical injuries to the eyeball \x01 Mechanical injuries to the eyeball Corneal ulceration causes Gradual painful defective vision Reference : AK KHURANA COMPREHENSIVE OPHTHALMOLOGY, Edi4, Page-462', 'role': 'assistant'}]