Diabetic retinopathy is the leading cause of blindness in patient aged 20-64 years. It is extremely important for diabetic patients to evaluate their retina and maintain their regular dilated fundus examinations. It is possible to have diabetic retinopathy for a long time without noticing symptoms until substantial damage has occurred.
Symptoms may include:
Blurred or distorted vision, difficulty reading, difficulty with color perception, appearance of spots (commonly called “floaters”), shadow across the field of vision and eye pain or pressure.
Diabetic retinopathy is caused by the damage that the elevated sugar levels cause in the small blood vessels that nourish the retina and may, in some cases block them completely.
Possible ocular manifestations of diabetes includes:
Diabetic macular edema, non proliferative diabetic retinopathy, proliferative diabetic retinopathy, vitreous hemorrhage, tractional retinal detachment, ischemia (poor circulation) of the retina and high ocular pressure.
Diabetic macular edema occurs when damaged blood vessels leak fluid into the retina causing swelling in the center (macula) which is the area of the retina responsible for the sharp vision needed for reading and recognizing faces.
Proliferative diabetic retinopathy occurs when prolonged damage to the small vessels in the retina result in poor circulation prompting the development of growth factors that simulate new abnormal vessels and scar tissue to grow on the surface of the retina. Vitreous hemorrhage is developed when the abnormal new vessels (from proliferative diabetic retinopathy) bleed into the middle of the eye.
Tractional retinal detachment is developed when the abnormal new vessels and scar tissue from proliferative diabetic retinopathy pull on the retina.
High ocular pressure and pain can be occur if the abnormal new vessels grow on the iris, clogging the drainage system of the eye.
Factors that increase the risk of developing diabetic retinopathy are:
Disease duration, poor control of blood sugar over time, high blood pressure, high cholesterol and pregnancy.
Diagnostic testing includes dilated eye exam, optical coherence tomography (OCT), fundus photo and fluorescein angiography.
Dilated eye exam is done after drops are placed in the eyes to dilate (open widely) the pupils. The physician will look for swelling (diabetic macular edema), evidence of poor retina blood vessel circulation, abnormal blood vessel and new blood vessels or scar tissue.
Optical coherence tomography (OCT) test provides highly detailed cross-sectinal images of the retina that show its thickness. It is useful in the evaluation of macular edema (retina swelling).
Fundus photographs helps detect and document diabetic retinopathy. These photos make it easier to monitor the disease on follow-up visits and to determine if it is worsening.
Fluorescein angiography (FA) is helpful in the assessment of the circulation, active leakage areas, presence of ischemia and neovascularization. Additional valuable information is provided when modern ultra-widefield, ultra-high resolution equipment is utilized such as Optos. It enables a simultaneous pole to periphery view of the retina allowing the entire retina vasculature to be imaged during the dye transit.
Several treatments are available to treat the different manifestations of diabetic retinopathy. Treatment options include intravitreal injections, laser and vitreoretinal surgery.
Intravitreal injections (small injections of medications into the middle cavity of the eye) have been very useful in cases of diabetic macular edema, selected cases of proliferative diabetic retinopathy and vitreous hemorrhage, before vitreoretinal surgery (to decrease the risk of bleeding during surgery) and to slow down the progression of the diabetic retinopathy.
Intravitreal injections are divided in two groups: anti-vascular endothelial growth factors (anti-VEGF) and steroids & steroid implants. Anti-VEGF block the vascular endothelial growth factor, a chemical signal that stimulates leakage and abnormal blood vessel growth. Repeated doses may be needed to prevent blood vessels from leaking fluid and causing vision loss. Some eyes with diabetic macular edema respond better to intravitreal steroids injections than to anti-VEGF injections.
Retina laser is used in the treatment of certain cases of diabetic macular edema (modalities include focal laser and micropulse laser) and in proliferative diabetic retinopathy (treated with panretinal photocoagulation).
Vitreoretinal surgery is recommended when tractional retinal detachment is present and/or non clearing vitreous hemorrhage.
To prevent and decrease the risk of complications it is recommended to take your medications as prescribed by your doctor, reach and maintain a healthy weight, exercise, stop smoking, control your A1C, blood pressure and cholesterol.
It is extremely important for diabetic patients to maintain the eye examination schedule as recommended by the retina specialist. Timely diagnosis and treatment can prevent and decrease the risk of future visual loss and preserve your vision.