Diabetic retinopathy

Diabetic retinopathy is a common condition that develops in patients with hyperglycemia for prolonged periods, as occurs in diabetes mellitus, either type I or type II. While a wide range of effects on the retina exists, frequent screening exams are necessary to identify people at risk of significant visual impairment if left untreated.


What is diabetic retinopathy?

Elevated blood sugar leads to modification of proteins and other components inside of blood vessels. These modifications can be damaging to the eye’s circulation. When these tiny vessels are bathed in elevated blood sugar levels for many years, they become brittle, close off (capillary drop-out) or break (causing small hemorrhages). The leakage of blood, fluid and cholesterol from these fragile vessels can lead to blurry vision. When leakage occurs in the macula, this is called diabetic macular edema. When new blood vessels grow, this is called retinal neovascularization. Neovascularization can lead to bleeding in the vitreous cavity, which is called vitreous hemorrhage, and also lead to fibrotic tissue that contracts and detaches the retina (traction retinal detachment).


What causes diabetic retinopathy?

Hyperglycemia over the course of years as is encountered with diabetes mellitus. Hypertension can worsen diabetic retinopathy as well.


What are the symptoms of diabetic retinopathy?

This varies from no symptoms to severe loss of vision. Some will note blurry vision or central visual distortion (metamorphopsia). This can be due to macular edema, which describes swelling of the macula. Vitreous hemorrhage may present with floaters in one’s vision progressing to a near complete obscuration of vision. A retinal detachment caused by diabetes can present with poorly defined blurry vision with floaters, but symptoms vary depending on the age and severity of the detachment.


How is diabetic retinopathy diagnosed?

A dilated eye exam utilizing hand-held lenses, optical coherence tomography of the retina, fundus photography, and fluorescein angiography may be used in combination to identify and/or evaluate the condition. An ultrasound machine can be used to assess the positioning of the retina when a vitreous hemorrhage makes it impossible to directly visualize the retina.


What are the treatments for diabetic retinopathy?

Managing diabetes and hypertension is paramount to preventing retinopathy. Angiogenesis inhibitors are the first-line treatment for macular edema, but steroid injections and focal laser treatment are also utilized. Scatter laser treatment to retina with poor blood flow (ischemic retina) may be necessary to promote regression of neovascular tissue. Vitrectomy may be necessary to hasten recovery of vision after a vitreous hemorrhage, or to treat a retinal detachment.