Top images: normal retina in right and left eye
Bottom images: diabetic bleeding and yellow lipid deposits in the retina causing blurred vision in both eyes
When patients carry a diagnosis of diabetes for many years, they run the risk of developing diabetic damage in the eyes, called diabetic retinopathy. The retina refers to the thin layer of nerve tissue that lines the back wall of the eye and contains millions of light-detecting cells that receive stimuli from the visual world and sends the signals to the brain for processing. The suffix -pathy confers the meaning "disease of" from the Greek origin.
How does diabetes cause eye damage?
Diabetes causes elevated levels of sugar in the blood. These sugar levels cause damage to the small blood vessels that supply the retina with oxygen. This blood vessel damage triggers a cascade of events that can affect a patient's vision in a number of ways.
How is diabetes diagnosed?
Diabetes is typically diagnosed by the primary care physician or endocrinologist after measuring a fasting blood sugar level of 126 or greater; a two-hour blood sugar level of 200 or greater during an oral glucose tolerance test; or a random blood sugar level of 200 or greater in a patient with certain symptoms, such as thirst, increased appetite, frequent urination, weight loss, and dehydration. The Hemoglobin A1C (HA1C) level has also recently been included in the diagnosis of diabetes, with a value of 6.5 or greater.
How does diabetes affect my vision?
The three most common mechanisms by which diabetes affects a person's vision are listed below:
1) leakage of fluid through the damaged blood vessel walls into the retina. This process is the most common cause of vision loss due to diabetes.
2) closure of certain blood vessels, depriving retina of oxygen
3) new blood vessel growth; which can lead to bleeding into the eye, membrane proliferation, and even retinal detachment.
Can my vision be improved?
The good news about diabetic retinopathy is that vision loss is preventable if caught in the early stages. Working with the primary care physician or endocrinologist to optimize diet, exercise, and diabetic medications can improve the findings of diabetic retinopathy.
In the intermediate stages, the vision can be improved with either injections, steroid implants, or laser procedures in the office. In the advanced stages, surgery may be required to improve the vision. Some aspects of vision loss due to diabetic retinopathy, especially in the advanced stages, are irreversible. The best chance of optimizing the visual outcome comes with consistency of attending eye care appointments and adhering to recommended treatments.
How often should my eyes be examined?
The updated American Diabetes Association guidelines recommend that children 10 years of age or older receive a dilated eye examination within 5 years of being given a diagnosis of Type 1 Diabetes. Adults should receive a dilated eye examination shortly (weeks) after their diagnosis of Type 2 Diabetes.
If no diabetic eye damage is detected, the eyes should be examined yearly. If any level of retinopathy is identified, more frequent exams will be necessary, from every 6-9 months in the early stages; to monthly if receiving treatments like injections or lasers. The periods between eye exams can be extended once the disease process is halted and the eyes stabilize.