Diabetes that is not optimally managed puts one at risk for eye-related issues ranging from cataracts to retinopathy to glaucoma. In fact, it is the leading cause of blindness in people aged 18 to 64. With regular care and attention, however, many people with diabetes are able to protect their vision. Diabetic retinopathy and diabetic macular edema are often mentioned in tandem, but they are not the same thing.