They are fragile and can cause blindness by hemorrhaging or retinal detachment. Diabetic retinopathy develops gradually over many years. Type I diabetes, those requiring insulin to control their blood sugar, and patients with diabetes for many years are at an increased risk for developing retinal problems. Poor control of the blood glucose, pregnancy, uncontrolled high blood pressure, and smoking also aggravate diabetic retinopathy. You can't diagnose diabetic retinopathy by looking in the mirror since your eye will usually look and feel normal.
Vision is also often normal despite the presence of potentially blinding eye conditions.
Only a thorough retinal examination through a dilated pupil can detect these problems. Properly timed laser treatment can effectively stabilize vision although it is less likely to improve it. The key to maintaining good eyesight, therefore, is early diagnosis and treatment before symptoms occur. Most diabetic patients need dilated eye examinations at least once a year throughout their lifetime. Further testing, including photography and fluorescein angiography, may be done to assist in the diagnosis and treatment of any changes thought to cause visual loss.