Hello Doctor, My brother-in-law has a problem in his right eye. Age - 38 Diabetic person He has cataract and retina problem. Consulted doctor said we have to remove cataract first, then oil kind of liquid need to be drop on eye for 6 months to treating retina. During this period he won't be have vision and all on that eye. Is it true? After cataract removal no vision or partial vision? How long it will take to treat retina and get back to normal vision? Please answer my queries.