Learn how diabetes impacts your sight. Explore common symptoms, prevention tips, and treatment options to protect your vision from diabetic eye diseases.

How Diabetes Affects Your Vision: A Guide to Eye Health

Diabetes, the inability of the body to regulate blood sugar levels, can have long-lasting effects on your vision and eye health. These can include blurry vision, diabetic retinopathy, diabetic macular edema, cataracts, glaucoma and others. You can help prevent these conditions by maintaining healthy blood sugar levels and by scheduling regular comprehensive eye exams to determine the extent of any vision loss. Further damage can be prevented by medication, laser therapy or surgery, depending on the condition and stage of progression.

The Connection Between Blood Sugar and Sight

How High Glucose Impacts the Lens and Retina: Over time, too much glucose in the blood damages the retina in the back of the eye, particularly in the central area known as the macula. This damage causes bleeding into the eye and swelling of the lens and macula, gradually leading to a reduced ability for the retina to detect light and colors. Left untreated, this condition, called diabetic retinopathy (DR), can result in permanent blindness.

The leading cause of blindness among American working-age adults, DR can develop in anyone with type 1 or type 2 diabetes. Chances for developing DR increase the longer someone has had diabetes. Other risk factors for DR include high blood pressure (hypertension), high cholesterol, kidney disease, and smoking. In addition, according to the Centers for Disease Control and Prevention (CDC), African-Americans, American Indians/Alaska Natives, and Hispanics/Latinos are also at greater risk for DR.

Common Symptoms of Diabetes-Related Vision Loss

Identifying Blurred Vision and Fluctuating Sight: Blurry vision can be an early warning sign of diabetic eye disease, particularly DR. It can also be caused by swelling of the lens. Since DR initially causes few or no symptoms in many cases, it’s important to schedule an eye exam as soon as you notice fluctuations in your vision. Early detection and treatment are vital to saving sight.

Recognizing Spots and Dark Strings (Floaters): According to the American Diabetes Association, floaters and spots can be the first sign of diabetic retinopathy. These shadows on the retina can be caused by clusters of cells or leaked fluid. Although floaters can be temporary, it’s important to schedule an eye exam if they persist due to their relevance in detecting DR.

Warning Signs of Impaired Color Vision: Since the macula is responsible for color vision, a fluctuation in this area can be a sign of DR. According to the Child and Family Vision Center, impaired color vision caused by diabetes can lead to colors appearing faded, and blues and yellows looking similar. Slight errors when judging distances can also indicate a change in depth perception caused by diabetic eye disease.

Beyond Retinopathy: Other Diabetes-Related Eye Conditions

Diabetic Macular Edema (DME) and Central Vision: Weakening of the blood vessels in the retina causes them to leak fluid. This in turn causes the macula, responsible for central vision, to swell with fluid, distorting vision. This condition, called diabetic macular edema (DME), occurs in roughly half of patients with DR and is the most common way for DR to result in blindness.

The Increased Risk of Early-Onset Cataracts: Most people develop cataracts as they age, but high blood sugar levels increase the risk that these will form earlier in life. This can be due to deposits of protein and fiber building up in the lens and making it appear cloudy. According to the CDC, hypertension, obesity, too much exposure to sunlight over time, and smoking can also contribute to cataract development.

Understanding Neovascular Glaucoma: Diabetes can also lead to the onset of neovascular glaucoma. This arises when fluid builds up in the eye due to new blood vessels growing on the iris. The fluid is blocked from leaving the eye, leading to intraocular pressure and damage to the optic nerve. To be treated most effectively, glaucoma must be caught early, which is why regular comprehensive eye exams are so important. According to the CDC, people with diabetes are also twice as likely to develop open-angle glaucoma.

Mitigation and Prevention: Protecting Your Eyesight

The Importance of Comprehensive Dilated Eye Exams:  Comprehensive dilated eye exams are the most reliable way to detect warning signs of any of the above diseases. If caught early enough, some can be treated with no or relatively minimal permanent vision loss. During the eye exam, the ophthalmologist will administer eye drops that dilate or enlarge the pupils. This allows the eye doctor to check for any problems with the lens or retina that may be a sign of diabetic eye disease. The American Academy of Ophthalmology (AAO) recommends one eye exam in the twenties, two in the thirties, and one every one to two years for older adults. However, it is always important to schedule an eye exam if you notice changes in your vision.

Managing A1C Levels to Reduce Eye Damage:  High A1C levels are a common indicator of pre-diabetes as well as the likelihood of DR. A large part of preventing or mitigating diabetic eye disease is simply to keep diabetes itself in check. Eating healthy, not smoking, remaining active and other general health practices can help prevent pre-diabetes from progressing.

Blood Pressure and Cholesterol Control for Ocular Health:  Hypertension and high cholesterol are also indicators of pre-diabetes, and both increase the likelihood of DR. General guidelines for lowering one’s risk for diabetes, including a healthy diet, not smoking, and exercising, are good ways of mitigating diabetes and diabetic eye diseases before they progress.

Treatment Options for Vision Preservation

While diabetic eye diseases cannot be reversed, various treatments are designed to preserve remaining sight. Since ophthalmologists can and do prescribe treatment before vision is noticeably affected, the earlier treatment starts, the more sight is preserved.

Laser Therapy and Anti-VEGF Injections: Laser therapy works by burning and sealing off blood vessels in the retina. Anti-VEGF injections (corticosteroids) inhibit the growth of new, abnormal vessels. Both preserve sight by attacking the most common problems leading to vision loss: swelling of the macula, intraocular pressure from fluid buildup, and clumps of blood vessels that block part of the visual field.

Surgical Interventions for Advanced Vision Issues: Surgery can be used to treat diabetes-induced cataracts or glaucoma. Often this is accomplished via a vitrectomy, the removal of some of the vitreous fluid. This procedure can also be used as part of retina reattachment surgery in some patients with DR, or to remove floaters.

Lifestyle Adjustments for Long-Term Eye Wellness

Since a large part of preventing diabetic eye disease is preventing diabetes itself, simple lifestyle choices such as healthy eating and exercising can have an outsized impact on the long-term health of the eyes.

Dietary Choices That Support Retinal Health: The American Academy of Ophthalmology has information about foods that contribute to eye health. Well-known essential nutrients for the eye include various antioxidants, zinc and vitamins A, C, and E. Carrots are best known for their effects on eye health, but these nutrients can also be gained from eating a wide variety of fruits, vegetables, legumes, and eggs.

The Impact of Physical Activity on Ocular Pressure: According to the Glaucoma Research Foundation, studies have shown that aerobic exercise, such as many cardio workouts, may help lower intraocular pressure, leading to reduced risk and severity of glaucoma. This is in addition to its effects mitigating the progression of pre-diabetes and diabetes generally.