Eye Tests And Diabetes

The eyes may be the window to the soul, but they are also a window into determining many different health conditions including diabetes. Individuals with diabetes may develop a group of different conditions that are collectively known as diabetic eye disease. Sometimes early signs of diabetes may be noted during an ophthalmology examination, or because of a diagnosis of diabetes more comprehensive eye examinations may be required on an annual basis.


Many people with diabetes, both type 1 diabetes and type 2 diabetes that have unregulated blood glucose levels, experience a blurring of vision. This occurs because of the high glucose levels cause the lens in the eye to swell. When this happens, you have difficulty focusing and things appear blurry. This condition may come and go for a short period of time and, without proper blood glucose regulation, permanent damage can occur.

More significant disease of the eyes are also common in people with diabetes. These can lead to partial or complete vision loss, which is a complication that accounts for approximately 12,000 to 24,000 cases of blindness every year. 1 Gradual vision loss and decrease in the quality of life because of vision impairments is another factor that many people with diabetes will need to deal with because of unregulated blood glucose levels.

Projected levels for diabetic retinopathy and other eye conditions for those diagnosed with diabetes are estimated to continue to increase. In a recent research finding it is estimated that the number of patients over the age of 40 with cataracts due to diabetes will increase 235% by 2050 and the number of people with diabetic retinopathy or vision threatening diabetic retinopathy will triple. The most dramatic increase is anticipated to be in the Hispanic population over the age of 35 where glaucoma cases will increase 12 times over current diagnosis numbers. 2

Understanding Diabetic Retinopathy

Diabetic retinopathy is a specific condition that occurs when there is damage to the small blood vessels that provide blood flow to and from the retina. There are actually four different stages of diabetic retinopathy that range from mild vision impairments to significant vision impairment. Early diagnosis and treatment can minimize the risk of progression of the disease and can limit the risk of developing any type of vision problems.

The first stage of diabetic retinopathy is known as mild nonproliferative retinopathy and typically there are no changes in vision. However, it is important to understand that blood vessels are swelling and forming microaneurysms that can lead to step two, which occurs when blood vessels become blocked due to the swelling. In severe nonproliferative retinopathy significant numbers of blood vessels are blocked and the body tries to form new blood vessels to carry blood to the retina. Once these new blood vessels start to form the condition is in stage four or proliferative retinopathy. The new blood vessels grow along the retina and into the vitreous gel in the eye. These are very thin blood vessels that, with high blood pressure, can leak blood into the vitreous gel or the surface of the retina. This causes black spots throughout the field of vision and can result in full blindness if enough bleeding occurs.

Macular edema can also occur, which is a swelling of the macula or the focus area of the eye. Once this happens vision problems will occur that lead to increased blurring and lack of focus. Typically the first signs of diabetic retinopathy include spots in the field of vision that may come and go, at least initially.

Cataracts and glaucoma are also very common in people with diabetes. This is due to the high blood pressure and high blood glucose levels found in individuals with the condition.

Eye Tests

During annual eye exams your ophthalmologist will use several tests to ensure that diabetes is not contributing to any vision problems. One very comprehensive test is the dilated eye exam. Most people have had this exam and it is painless but does cause some shortterm vision problems. Drops are placed in the eye that will cause it to dilate. The ophthalmologist then is able to look into the retina and check for any signs of swelling, macular edema, or any changes in the blood vessels surrounding the retina. The optic nerve is also visible and can be examined with specialized enhanced lenses to determine if any damage due to hypertension is evident.

A tonometry test, which allows the eye care professional to test the pressure inside your eye, allowing an evaluation of the possibility of glaucoma. High pressure inside of the eye is very serious and can be addressed through medications as well as increased care in blood glucose regulation, health and lifestyle choices.

A standard vision test will also be performed. It is important to talk to your eye care professional about any blurred vision, spots in the visual field or changes in eye sight and visual acuity.

If macular edema is present a more comprehensive test of the blood vessels of the eye may be required. This is completed using a fluorescein angiogram. In this test the doctor injects a small amount of special dye into the large blood vessels in the arm that allows the doctor to trace any blood vessel leakage in the eye. This test can evaluate the extent of the blood loss from the vessels, allowing a comprehensive treatment plan to be developed.

Early Detection and Prevention

Early detection of diabetic retinopathy, macular edema, glaucoma and cataracts is essential for preserving vision. In some situations, such as cataracts, surgery can be used to correct the vision problem. In other situations, if the problem is not diagnosed soon enough, permanent damage may occur. It is always best to catch vision problems early while they are relatively easy to treat, which is why the American Diabetes Association recommends yearly eye exams.


1 Skarbez, K., Priestley, Y., Hoepf, M., & Koevary, S. B. (2010). Comprehensive Review of the Effects of Diabetes on Ocular Health. Expert Review of Ophthalmology , 557-577.

2 Saaddine, J. B., Honeycutt, A. A., Vencat Narayan, K. M., et al. (2008). Projection of Diabetic Retinopathy and Other Major Eye Diseases Among People With Diabetes Mellitus. Archives of Ophthalmology , 1740-1747.


This article was originally published July 12, 2012 and last revision and update of it was 9/10/2015.