Your eye health may be the furthest thing from your mind if you have diabetes, but what you might not know is that the disease can directly impact your vision. According to the Centers for Disease Control and Prevention, diabetic retinopathy—a vision complication from diabetes leading to damage or swelling of blood vessels in the retina—is the most common cause of vision impairment and blindness in adults in the U.S. and by 2050 will affect roughly 14.6 million people.
That's not the only diabetes-related condition that can damage eye health. "Diabetic eye diseases can affect almost all parts of the eye and surrounding structures," says Matthew Gorski, M.D., a Northwell Health ophthalmologist at the Ophthalmology and Ocular Surface Center in Great Neck, NY. "The lens of the eye (where cataracts form) and the retina, the inside wallpaper where light rays are absorbed, are the most common areas where diabetes can cause eye problems."
Here, experts explain the main types of diabetic eye disease, the role glucose plays in the severity of these conditions, and most importantly, how people living with diabetes can protect their vision.
The Role of Glucose in Eye Health
High blood sugar can damage the pancreas, harden blood vessels, and over time, increase your risk of heart attacks and kidney disease. But in addition to these health risks, glucose that spikes too high can also harm your sight. "Fluctuations of blood-glucose levels significantly affect vision in both the short term and long term," says Orlin Sergev, M.D., Ph.D., owner of Equilibrium Endocrinology & Diabetes Center in Ladson, SC.
"In the short term, both high and low blood-glucose levels (especially with sudden changes) can cause vision to become blurry [due to fluid moving in and out of parts of the eye]," he says. "Long-term mismanaged glucose affects the blood vessels in the retina, which can cause permanent vision damage, including blindness."
This is why it's important for people with diabetes to see their eye doctor at least every nine to 12 months even if they have no symptoms, says Dr. Gorski, as the earliest stages of diabetic eye disease can often be asymptomatic.
Diabetic Retinopathy (DR)
Think of DR as the gateway condition to all other diabetic eye diseases. "With DR, elevated blood-glucose levels progressively damage the vessels in the retina, leading to swelling and bleeding that ultimately damages vision," says Dr. Sergev. "The severity is usually dependent upon the length of disease and the level of [glucose] control."
So while high glucose levels initially wreak havoc on blood vessels surrounding the eyes, affecting your vision by increasing blurriness or interfering with your ability to distinguish between colors, it's the continuous swelling and leaking of these vessels that can lead to other conditions like cataracts, glaucoma, and diabetic macular edema (DME).
How many people are affected by DR? The overall prevalence of diabetic retinopathy in adults with diabetes in the U.S. is 28.5%. There's also a class of diabetic retinopathy called vision-threatening diabetic retinopathy, and that's about 4.4% of diabetic adults.
"This means almost one-third of all diabetics have some form of diabetic retinopathy, and about five percent of them are going to have it severely affect their vision," says Dustin French, Ph.D., associate professor of ophthalmology at Northwestern University Feinberg School of Medicine in Chicago.
Currently, there's no known cure for diabetic retinopathy. However, retinal specialists can preserve sight and may reverse vision loss from diabetic retinopathy through various methods. Those might include injecting medication into the back of the eye, performing laser procedures, and/or retinal surgery.
According to the Mayo Clinic, [symptoms of DR] include (https://www.mayoclinic.org/diseases-conditions/diabetic-retinopathy/symptoms-causes/syc-20371611):
- Blurred or fluctuating vision
- Impaired color vision
- Dark or empty spots in your vision
- Vision loss
Diabetic Macular Edema (DME)
One of the most common eye conditions people with DR encounter (especially those with type 2 diabetes) is DME, which happens when uncontrolled blood sugar causes swelling of the retina, says Dr. French. This causes vessels in the eye to leak out or restrict blood flow, leading to a loss in the central-most part of your vision.
"Over time, this creates black spots in a person's vision as their vessels begin to deteriorate," says Dr. French. And while the thought of your vision being taken away can be terrifying, DME can be easily treated, says Dr. French. (Yet another reason to stay on top of those checkups.) Eye injections with anti-VEGF medications can manage the abnormal vessels and help prevent blindness. (OK, yes, they do require shots into your eye, but we can help you prepare for that.)
According to the American Academy of Ophthalmology, symptoms of DME include:
- Blurred or wavy central vision
- Colors appear washed out
- Difficulty reading
Cataracts and Glaucoma
Even if you aren't dealing with conditions like DR and DME, it's important to get your eyes checked regularly to stay on top of other eye conditions like cataracts (a clouding of the eye lens) and glaucoma (a group of conditions that damage the optic nerve). "Cataracts are five times more frequent in diabetics and glaucoma is two to three times more frequent," says Dr. Sergev.
Although the link between diabetes and cataracts is still murky, Dr. French says cataracts or glaucoma are often diagnosed at the same time a person gets screened for diabetic retinopathy, and this diagnosis may be due to certain lifestyle risk factors (such as smoking, excessive alcohol intake, or obesity) in addition to being diabetic.
What's more, the symptoms of cataracts and glaucoma, like blurry vision, distortion, and other eyesight changes, can often overlap with more serious conditions like DR and DME. This is why in addition to maintaining your glucose levels, eating a well-balanced diet, and not smoking, people with diabetes should closely monitor their eye health with a yearly dilated eye exam to help decrease the chances of developing diabetic eye disease—as well as get proper treatment for any eye issues that do arise as quickly as possible.