Hi, my brother had optic entities in both eyes. 1 is about 80% blind other about 20%. just recent, the eye doc told him his 20% eye small vessels is bleeding in the back. what can be causing this? he has diabetes, but made sure its controlled now?

Unclear to me what you mean by "optic entities". Sounds like he has retinal damage, which can occur unfortunately with diabetic retinopathy. Certainly, less common disorders could be co-morbidities. This is a situation that may require a retinal specialist, and perhaps help at a local medical school Eye Dept. ?if laser therapy might help?

Diabetes causes damage to small blood vessels all over the body including the eyes, kidneys, brain, heart, and feet. Controlling blood sugar and blood pressure slows down the damage, but old damage remains. Anti-VEGF injections and laser treatment are very helpful in treating diabetic retinopathy. www.mayoclinic.org/diseases-conditions/diabetic-retinopathy/diagnosis-treatment/drc-20371617