Diabetes and Your Eye Health

Diabetes mellitus (DM) is a major medical problem throughout the world. Diabetes causes an array of long-term systemic complications that have a considerable impact on the patient as well as society, as the disease typically affects individuals in their most productive years. An increasing prevalence of diabetes is occurring throughout the world. 

Patients with diabetes often develop ophthalmic complications, such as corneal abnormalities, glaucoma, iris neovascularization, cataracts, and neuropathies. The most common and potentially most blinding of these complications, however, is diabetic retinopathy,  which is, in fact, the leading cause of new blindness in persons aged 25-74 years in the United States. Approximately 700,000 persons in the United States have proliferative diabetic retinopathy, with an annual incidence of 65,000. An estimate of the prevalence of diabetic retinopathy in the United States showed a high prevalence of 28.5% among those with diabetes aged 40 years or older.

The retina needs a constant supply of blood, which it receives through a network of tiny blood vessels. Over time, a persistently high blood sugar level can damage these blood vessels in 3 main stages:

• background retinopathy – tiny bulges develop in the blood vessels, which may bleed slightly but don't usually affect your vision
• pre-proliferative retinopathy – more severe and widespread changes affect the blood vessels, including more significant bleeding into the eye
• proliferative retinopathy – scar tissue and new blood vessels, which are weak and bleed easily, develop on the retina, this can result in some loss of vision

In the initial stages of diabetic retinopathy, patients are generally asymptomatic, but in more advanced stages of the disease, patients may experience symptoms that include floaters, distortion, and/or blurred vision. Microaneurysms are the earliest clinical sign of diabetic retinopathy.

Diabetic retinopathy can be minimized with a combination of strict blood sugar control and routine screening with eye exams. Studies have shown that maintaining near-normal blood sugar levels can decrease the chance of developing retinopathy and can help keep existing retinopathy from getting worse. That may include insulin and other medications, dietary modifications, and exercise. Intensive insulin therapy, which may include frequent blood sugar testing and the use of an insulin pump, may be an option.

Intensive therapy reduced the mean risk of retinopathy by 76% (95% CI 62–85). According to the studies, improved blood glucose control reduced the risk of developing retinopathy and nephropathy and possibly reduces neuropathy. The overall rate of microvascular complications decreases by 25% in patients receiving intensive therapy versus conventional therapy. Epidemiological analysis of the UKPDS data showed a continuous relationship between the risk of microvascular complications and glycemia, such that for every percentage point decrease in HbA_1c (e.g., from 8 to 7%), there was a 35% reduction in the risk of microvascular complications.

Do not wait until you notice vision loss, dark spots, or other abnormalities to see an ophthalmologist. With regular screenings, your doctor can detect eye disease early and help to preserve your vision. The American Diabetes Association’s 2017 Standards of Medical Care recommends:

• Adults with type 1 have a dilated eye exam within five years of their diabetes diagnosis.
• Kids who have had type 1 diabetes for three to five years should get a comprehensive eye exam at age 10 or after puberty has begun, whichever is earlier.
• People with type 2 have a dilated eye exam at the time of their diabetes diagnosis.
• People with type 1 and 2 have annual dilated eye exams. If there is no evidence of retinopathy for one or more annual exams and blood glucose is well managed, doctors may recommend eye exams every two years.
• Women with diabetes receive an eye exam before becoming pregnant or in the first trimester. Pregnancy can hasten the start or progression of diabetic retinopathy.

Nevertheless, prevention of Diabetic microvascular complications i.e. retinopathy, neuropathy, and nephropathy is the best cure.