A 35-year-old insulin dependent Diabetes Mellitus (iddm) patient on insulin for the past 10 years. He complains of gradually progressive painless loss of vision. Most likely he has:

Cataract - pre senile cataract, so is likely possibility here and is answer of choice. Vitreous hamorrhage would be sudden and more so in proliferative diabetic retinopathyso excluded. Total rhegmatogenous retinal detachment would be sudden so excluded. Tractional retinal detachment not involving the macula - at periphery this won't cause loss of vision so should not be the answer here.