Diabetic retinopathy refers to any kind of retinal damage caused by diabetes including bleeding, abnormal vessel growth and fluid leakage. The retina, located at the back of the eye, is comprised of nerves that sense light and send images to the brain. When retinal blood vessels are damaged, they may leak fluid or blood, and may also develop abnormal vessels and scar tissue. These changes in the retina can cause blurred, distorted or obscured vision. Sight is generally not affected at this stage.
Macular edema is a more serious condition.
It occurs when leaking blood or fluid collects in the macula, a small area at the center of the retina that is responsible for detailed vision. Persons with macular edema have difficulty reading fine print or doing any kind of close work such as threading a needle. However, the changes in vision may be gradual, and a thorough medical examination is the only sure way to diagnose this condition. Proliferative retinopathy is the most serious form of diabetic retinopathy, and 20 percent of people with diabetes are affected by this form. The condition occurs when fragile, abnormal blood vessels that have grown on the retinal surface begin to break open and bleed into the vitreous, the clear substance that fills the eye.