What are the most serious diabetic eye problems?

Retinal complication. Diabetes can be associated with many eye problems. Retinal complications, especially proliferative retinopathy can cause severe loss of vision from decreased blood supply, hemorrhage, and retinal detachment. Macular edema is swelling in the retina affecting the central vision. Both conditions are treatable, but early diagnosis is key. Cataract, increased glaucoma risk, change in refraction also.
See a retina special. Diabetes damages blood vessels in the retina causing bleeding and swelling (diabetic macular edema - dme): nonproliferative diabetic retinopathy. This is the most common kind and the kind that causes the most vision loss (from dme). When new abnormal blood vessels grow along the retina (proliferative), this can cause bleeding (vitreous hemorrhage), traction (retinal detachment), and/or glaucoma.