Diabetic retinopathy is the number one cause of visual loss in patients aged 20-64 years in the United States. It is caused by hyperglycemia(high blood sugar) induced damage to the tiny blood vessels in the retina. The risk of diabetic retinopathy is closely related to the duration of diabetes, control of blood sugar, and associated medical conditions such as hypertension, kidney, and heart disease. In its early stages, diabetic retinopathy cause very little visual symptoms if any, causing a delay in patients seeking eye care. Patients often have advanced disease stage by the time they come to the doctor's office with visual symptoms. In addition, many patients do not have optimal sugar control for a variety of reasons contributing to severe and rapid progression of the disease despite treatment. It is there imperative for anyone with diabetes to have a regular dilated retina evaluation to detect diabetic retinopathy as early as possible and maintain best possible blood sugar control.
There are two clinical stages of diabetic retinopathy:
• Nonproliferative diabetic retinopathy: Patients develop tiny hemorrhages, microaneurysms, and leakage of fluid from the damaged blood vessels.
• Proliferative diabetic retinopathy: Abnormal new blood vessels form on the surface of the retina, causing hemorrhage and retinal detachment.
Patients with either clinical stage of diabetic retinopathy may develop macular edema. Macular edema results when the center of the retina, called macula, develops swelling from the leaking blood vessels. The swelling of the macula leads to dysfunction of the photoreceptors and resultant blurred vision.
Medical management of diabetic retinopathy: The most important factor in the medical management of diabetic retinopathy of course is to maintain good blood sugar control. The Diabetes Control and Complications Trial showed that intensive control of blood glucose is associated with reduced risk of newly diagnosed diabetic retinopathy and reduced progression of existing diabetic retinopathy. The United Kingdom Prospective Diabetes Study also showed that the control of hypertension was also beneficial in reducing the progression of diabetic retinopathy and loss of vision.
Laser treatment of Diabetic Retinopathy: Laser is an intense focused beam of light of certain wavelength that can be used to photocoagulate tissues. It is used to prevent further growth of abnormal blood vessels in proliferative diabetic retinopathy and to stop leaking blood vessels to prevent macular edema. Several national studies have clearly demonstrated the effectiveness of laser treatment in reducing the risk of developing severe visual loss. It is the primary treatment used by retinal specialists for diabetic retinopathy. There are certain criteria used in deciding when the laser treatment is appropriate for a given patient based national studies. This determination requires dilated retinal examination, and sometimes special diagnostic tests such as fluorescein angiogram. The location and the size of retinal swelling relative to the center of the retina, as well as the presence of hemorrhages within the vitreous cavity and the size of the abnormal blood vessels, are the major determinants of whether a laser treatment is warranted. Panretinal laser treatment is used for proliferative diabetic retinopathy, whereas macular laser treatment is used for macular edema. Panretinal laser is applied to the peripheral retina in a scattered fashion to reduce the area of diseased retina, which helps discourage the growth of abnormal blood vessels. Macular laser is applied directly to the leaky blood vessels to prevent continued leakage, which helps prevent macular edema. Panretinal laser can reduce the rate of severe visual loss by 50% or more. Macular laser can reduce the rate of moderate visual loss by 50%.
Intraocular Injection for Diabetic Retinopathy:- Intravitreal anti-VEGF drugs: Avastin, Lucentis, Vabysmo, Eylea and Eylea HD are agents given by injection to treat macular edema.
- Intravitreal steroid injection: Administration of intraocular corticosteroids such as Kenalog or Ozurdex, can reduce macular edema.
- Par plana vitrectomy: This is an operating room surgical procedure performed in the setting of severe diabetic retinopathy. The indications for the procedure include non-clearing severe vitreous hemorrhage, retinal detachment, and diffuse macular edema, which have not responded to other treatment modalities. The procedure involves making three tiny incisions into the vitreous cavity. Special microinstruments are inserted through the incision to remove blood and scar tissues, apply laser, and perform other necessary steps.
Since diabetic retinopathy is caused by a systemic disease associated with high blood glucose, the prognosis for diabetic retinopathy in a given patient ultimately depends on how well he or she controls her diabetes. Please ask and get help from your doctor. Please have regular examinations, keep your hemoglobin A1C below 7, control your blood pressure and cholesterol, and check for any heart or kidney diseases. Please have your retina examined regularly with dilation to detect and treat diabetic retinopathy.