NHS warns of eye red flag as potential diabetes symptom. Blurred vision indicates diabetes risk, leading to possible sight loss if untreated. Diabetes symptoms should be promptly addressed, with eye screenings for diabetics over 12. Other diabetes symptoms include increased thirst, fatigue, and slow wound healing. Vision changes could indicate diabetic retinopathy, a complication of high blood sugar. Monitoring blood sugar levels can help prevent diabetic retinopathy. Speak to a GP if experiencing any diabetes symptoms.