Normal. Because of the retinal detachment would have been unable to see things , will only feel the bright light. How long will it take to see? I'm afraid that's not good. The light will definitely get wider as the condition improves. But it's unlikely that you'll be able to see clearly, at 50 years old and with diabetes. The kind of retinal detachment that small children can't see well even after it's cured, a blurry state that generally doesn't change at all. Unless the surgery is done within a week of the retinal detachment, then it will still recover. Otherwise, there's no way around it.
Don't be too sad, many things are not something we can change.