The impact of diabetes on vision

Dr. Omar P. Haqqani

Dr. Omar P. Haqqani

The negative impact diabetes has on areas of the body and organs, including kidneys, heart and nerves have been well documented. However, there is a new emphasis on the relationship between diabetes and the eyes. The number of people with diabetes-related vision problems globally is estimated to increase to 180.6 million in 2030. The figure reported in 2014 was 146 million. According to the Centers for Disease Control and Prevention, diabetes is the leading cause of new cases of blindness in adults in the United States. 30.3 million Americans, or 9.4 percent of the population, have diabetes.

How does diabetes affect vision?

Diabetes occurs when blood glucose, also called blood sugar, is too high. Blood glucose is the main source of energy and comes from food. With diabetes, the body does not produce enough insulin, the hormone that processes glucose. It can be absent or its production can be impaired (TYPE 1) or there can be "insulin resistance" of tissues to insulin (TYPE 2).

Diabetic retinopathy (DR) occurs when the blood vessels of the retina are damaged. Increased sugar levels in the blood resulting from diabetes causes this damage. The macula, an oval-shaped pigmented area in the central retina responsible for high-resolution and the color vision, can develop edema; the entire retina is at risk of rogue blood vessels hemorrhaging into the retina or detaching it.

The American Society of Retina Specialists (ASRS) states that diabetic retinopathy is the leading cause of blindness in Americans of working age. People with Type 1 diabetes are as likely to develop diabetic retinopathy as those with Type 2 diabetes.

In addition to diabetic retinopathy, the risk of glaucoma and cataracts is greater for those with diabetes.

Symptoms of diabetic retinopathy

Most patients with DR have no symptoms until its latest stages, making screening a priority in preventing it. In Type 1 diabetes, DR begins within 5 years of their diabetes diagnosis; in Type 2, DR onset can take as long as 20 years.

When symptoms do occur, evidence of diabetic retinopathy may surface in one or both eyes. Blurred vision, eye pain, new difficulty in color perception or a shadow in the field of vision are among the most common symptoms. Having trouble reading or the presence of spots, called "floaters," in the vision are other symptoms.

Diagnosis and treatment

The best diagnostic approach for DR is screening. Early detection of changes that are unnoticed by the patient can allow early treatment to be more beneficial.

Screening is performed by an ophthalmologist or an appropriately trained specialist, and serial retinal photographs can be used to follow the progress of eye conditions. Ophthalmoscopy with the help of pupil dilation is used in conjunction with retinal photography.

Chronic hyperglycemia is the cause of the diabetic retinopathy. The diseased tissue of the retina provokes the growth of new vessels from adjacent ones in an attempt to revascularlize it. Neovascularization engenders the risk of hemorrhage and tractional retinal detachment.

The importance of early diagnosis of DR makes more likely any benefits from its management and treatment. Treatment is based on whether the retinopathy is nonproliferative (NPDR) or proliferative (PDR). The goal of NPDR treatment is preservation of remaining vision while reducing progression. PDR is a more progressive condition that mandates more aggressive treatment. Panretinal photocoagulation is the primary treatment for severe PDR and has been shown to reduce visual loss significantly.

If retinal detachment occurs, removal of the vitreous ("vitrectomy") helps reach the goals of therapy by stabilizing the intraocular environment.

Effective prevention methods include good management diabetes and hypertension management. Lipid-lowering therapy can also help.

To learn more about diabetic retinopathy, its symptoms and treatment, log on to and visit the Diabetes and Metabolism Institute.

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Dr. Omar P. Haqqani is the chief of Vascular and Endovascular Surgery at Vascular Health Clinics in Midland: