Diabetics can develop a number of diseases in the eye that can cause severe visual loss and blindness. Adults with diabetes are more likely to develop cataracts than non-diabetics and at an earlier age. There is also double the risk of developing glaucoma. Cataracts can be treated with surgery and glaucoma can usually be treated with drops.
Diabetic retinopathy is in the top severe complications from diabetes and is the leading cause of vision loss in adults 20 – 74. It occurs in approximately 80% of patients who have had diabetes for 10 or more years. Overall is present in 40 – 45% of all diabetics. Poor diabetic control increases the chances of developing diabetic retinopathy.
Stages of Diabetic Retinopathy
NPDR (non-proliferative diabetic retinopathy)
This is the early stage of diabetic retinopathy. A decrease in vision occurs with macular edema (swelling from leaky blood vessels) and macular ischemia (loss of blood vessels). Macular edema is treatable, but ischemia is not.
PDR (proliferative diabetic retinopathy)
This is the advanced stage of diabetic retinopathy. Abnormal blood vessels begin to grow. These fragile blood vessels can bleed and lead to a sudden loss of vision or floaters, macular edema and ischemia. These vessels can also cause scar tissue that can lead to a tractional retinal detachment.
What are the symptoms of Diabetic Retinopathy?
- Blurred vision
- Loss of vision
- Onset or increase in floaters
- Fluctuating vision
- Poor night vision
- Colors appear washed out or faded
- Area of loss of vision
How is Diabetic Retinopathy diagnosed?
Your eyes will be dilated as part of an ophthalmic exam. The ophthalmologist will examine your retina. The eye is the only organ where blood vessels can be examined. If signs of diabetic retinopathy are seen additional test such as optical coherent tomography and fluorescein angiography may be done. The fluorescein requires an injection of a dye into your vein and photography with a special camera. A more advanced OCT angiogram (OCTA) can diagnose these abnormal blood vessels WITHOUT the injection of a dye. We have the Optovue Avanti Wide OCT with OCTA at Sharper Vision Centers.
Intravitreal injections and laser are used to treat NPDR with macular edema and PDR. Surgery (vitrectomy) may be needed for non-clearing vitreous hemorrhage and scaring in the retina.
The use of laser has decreased after the introduction of intravitreal injections. For intravitreal injections, numbing drops are place in the eye followed by injection of xylocaine into the subconjunctival space. Also, a drop of povidone-iodine 5% solution is place on the eye to kill bacteria.
After a few minutes to allow adequate numbing of the eye, an intravitreal (into the eye) injection is performed. This is usually does not have pain but you one may have a feeling of pressure.
Pre and post injection antibiotics are not used. An American Academy of Ophthalmology recommendation.
Medication use in intravitreal injections for diabetic retinopathy:
Bevacizumid (brand name Avastin): This drug is used to treat cancers (colon cancer, lung cancer, glioblastoma, and renal-cell carcinoma). This drug inhibits blood vessel growth and decreases macular edema. It is used “off-label” for the eye.
Ranibizumad (Brand name Lucentis): Lucentis is a monoclonal antibody fragment created from the same parent antibody as bevacizumab. Its effectiveness is similar to bevacizumab at a much lower cost.
Afilbercept (brand name Eylea): Afilbercept is similar to ranibizumad with the addition of anti Placental Growth Factor (PIGF) which also stimulates the growth of new blood vessels.
The NEI-sponsored Diabetic Retinopahty Clinical Research Network found all three drugs to be safe and effective for treatment of diabetic macular edema for patients with a initial visual acuity of 20/40 or better. Aflibercept(Eylea) showed great improvement in patients with a initial visual acuity of 20/50 or worse.
Dr. Oyakawa was involved in a number of clinical trials for these medications
Corticosteroid (steroid) treatments:
Ozurdex is a dexamethasone intravitrel implant that has an effect that can last for upto 6 months. This can be implanted in the office.
Retisert is a fluoccinoloneacetonideintravitreal implant that can last for about 30 months. This implant insert in an operating room.
Iluvien is a fluoccinolneacetonideintravitreal implant that lasts about 36 months. This can be implanted in the office.
Corticosteroids are effective but havemajor side effects such as progression of cataracts and glaucoma.
Medical control of diabetes and blood pressure are very important.
The risk factors for loss of vision are duration of diabetes, blood sugar control, and hypertension.
Elevated blood sugar is one of the most important risk factor for diabetic retinopathy and diabetic macular edema. The Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) showed that control of blood sugar with a HgA1c of <7% (Average blood sugar level of 154 for 90 days) reduced the incidence of diabetic retinopathy by 76% and progression from early to advanced diabetic retinopathy by 54%. Thus, strict control of blood sugar is better to prevent diabetic retinopathy than trying to control it after its onset. Tight blood sugar control needs to be balanced against too low a blood sugar.
The Action in Diabetes and Vascular (ACCORD) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial showed that aggressive blood sugar control (HgA1c < 6.5) did not significantly reduce the risk of diabetic retinopathy development nor its progression in type 2 diabetes.
Many studies have identified hypertension as a risk factor for diabetic retinopathy and diabetic macular edema.
Dr. Oyakawa has seen patients decreasing the number of intravitreal injection for diabetic macular edema as their blood sugar control improved. Come see us today and let us help you!
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