Diabetic eye disease is a group of eye conditions that can affect people with diabetes.

Diabetic retinopathy affects blood vessels in the light-sensitive tissue called the retina that lines the back of the eye. It is the most common cause of vision loss among people with diabetes and the leading cause of vision impairment and blindness among working-age adults.
Diabetic macular edema (DME). A consequence of diabetic retinopathy, DME is swelling in an area of the retina called the macula.
Diabetic eye disease also includes cataract and glaucoma:

Cataract (Should link to Cataract Educational Page) is a clouding of the eye’s lens. Adults with diabetes are 2-5 times more likely than those without diabetes to develop cataract. Cataract also tends to develop at an earlier age in people with diabetes.

Glaucoma (Should link to Glaucoma Educational Page) is a group of diseases that damage the eye’s optic nerve—the bundle of nerve fibers that connects the eye to the brain. Some types of glaucoma are associated with elevated pressure inside the eye. In adults, diabetes nearly doubles the risk of glaucoma.
All forms of diabetic eye disease have the potential to cause severe vision loss and blindness.