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: Ophthalmology
ETDRS vision chart study is done in patients with diabetic retinopathy. ETDRS stands for – 
Select and explain. 
A. Extended therapy for diabetic retinopathy & its sutdy, B. Emergency treatment for diabetic retinopathy and study, C. Eye testing or rotatory drum & its study, D. Early treatment for diabetic retinopathy study
D: Early treatment for diabetic retinopathy study
Answer: D: Early treatment for diabetic retinopathy study 
Explanation: Early treatment diabetic retinopathy study (ETDRS) was a multicenter, randomized clinical trial involving 3711 participants designed to evaluate the effectiveness of both organ laser photocoagulation and aspirin therapy in the management of patients with non-proliferative diabetic retinopathy and early proliferative diabetic retinopathy.
In addition, it was designed to determine the best time to initiate photocoagulation treatment in diabetic retinopathy.