Definition: Non-proliferative diabetic retinopathy (NPDR) is the most common form of diabetic retinopathy. Early stages consist of edema and hard exudates, lipid that has leaked from abnormal blood vessels, in the central retina, resulting in blurred central vision. Later stages consist of vascular occlusion, a restriction of blood supply to the retina, as well as an increase in macular edema.
In the later stages, known as proliferative diabetic retinopathy (PDR), abnormal blood vessels and scar tissue grow on the surface of the retina and attach firmly to the back surface of the vitreous. The vitreous then pulls on the scar tissue and can cause the blood vessels to bleed into the vitreous cavity (an event called a vitreous hemorrhage). This may happen repeatedly in proliferative diabetic retinopathy and can cause immediate and severe visual loss. Often, the hemorrhage will clear by itself.
Treatment: The main treatment for NPDR is laser photocoagulation for macular edema. Many patients with significant macular edema are asymptomatic with good vision. It is therefore essential to diagnose and treat these patients during the early stage to prevent future visual loss. Treatment, done on an outpatient basis with topical or local anesthesia, seals areas of vascular leakage and significantly reduces the progression of severe visual loss.
For patients with PDR, a medication called Avastin, which is injected into the eye, may also be used to decrease recurrent hemorrhages. If the hemorrhage remains for a long period of time, a vitrectomy can be performed to remove the blood-filled vitreous with the aim of improving vision. Patients can also regain some vision if scar tissue is removed from the surface of the retina during the vitrectomy surgery. The surgeon removes the vitreous and scar tissue from the surface of the retina so that it stops pulling on the retina, eliminating wrinkling of the retina that causes blurry or distorted vision. This also decreases the possibility of future retinal detachments.
Although we can’t prevent the occurrence of diabetic retinopathy, good medical control and early diagnosis and treatment of retinopathy can significantly reduce the progression to severe visual loss. This obviously requires close cooperation between the primary physician, ophthalmologist and patient. The primary physician not only plays a key role in medical management, but assumes responsibility for patient education and coordination of care. All diabetics should be referred to an ophthalmologist upon diagnosis and then for periodic ophthalmic examinations.