Diabetes is a chronic, systemic metabolic disorder, and monitoring its signs and symptoms is important. This is true not just for your overall health and wellbeing, but also because diabetes can affect vision, with short- and long-term ramifications (including blindness).
An overview of diabetes
Whether you have diabetes or not, when you eat, your blood glucose (sugar) rises. The pancreas secretes insulin. Insulin is a hormone that helps lower blood glucose levels in the blood stream. It does this by getting blood sugar to your cells, so they can convert it to energy.
With diabetes, your body either doesn’t use insulin efficiently (type II) or it doesn’t make enough of it (type I). Your blood glucose becomes chronically elevated. Yet, your cells aren’t getting what they need to function. Type II diabetes sometimes gets labeled as not as much of an issue as type I. But this isn’t always the case. Both types can cause symptoms and problems—and affect vision. Even worse, type II diabetes may be present for quite some time before it is diagnosed, allowing damage to occur to cells and organs while it remains untreated.
How diabetes can affect vision + what to look for
Blood sugar and insulin have a tremendous effect on eye health and vision. When diabetes isn’t diagnosed, monitored, or managed well, chronically high blood sugar levels threaten more serious and even permanent damage to the eye or blindness. Diabetic eye disease includes several conditions, such cataracts, glaucoma, diabetic macular edema, and diabetic retinopathy. Vision becomes fuzzy, blurry, or distorted. For some people, these vision changes are the first clue that diabetes should be investigated. Never brush off these symptoms, even if they seem to correct or stabilize, as the symptoms can fluctuate as your blood sugars do.
Cataracts and glaucoma from diabetes
The anterior, or front, of the eye has a fluid called the aqueous humor. The cells in the lens of your eyes need glucose, just like the rest of the cells in your body. But, when blood glucose levels are high, the lens receives more glucose than it can metabolize, or use. It converts it to sorbitol, but this process happens slowly. As a result, fluid builds up in the lens fibers and causes the lens to swell. This is the primary cause for blurry vision in diabetic patients with poor blood glucose control and the reason diabetics are at higher risk of formation of cataracts.
High blood sugar puts you at risk for diabetic retinopathy, a condition where the blood vessels of the retina have been damaged. Unfortunately, one in three diabetics over age 40 have some indication of diabetic retinopathy and symptoms aren’t always present. When they do occur, you might notice changes in color perception, dark spots in your vision, increased floaters, or other symptoms. Take them seriously: blindness can occur with diabetic retinopathy. Contact your healthcare team to set up an appointment right away and be sure to have annual eye exams so that any problems can be identified early when they are most amenable to treatment.
Diabetic macular edema (DME)
Blood-vessel damage from diabetic retinopathy can eventually cause focal or diffuse diabetic macular edema (DME). DME occurs when leaky blood vessels allow fluid leakage around the macula. With DME, patients may first notice a decline in their ability to see clearly while driving or reading. This loss of visual acuity is because the macula is responsible for sharp, clear vision.
Along with blurry vision, DME can cause double vision, floaters, and also blindness. While there are some non-surgical treatments for DME, it may need to be corrected with surgery.
How to maintain healthy vision with diabetes
Diabetes can affect vision, but there are ways to maintain healthy eyesight. Anyone with diabetes needs to see an ophthalmologist for a yearly comprehensive eye exam. This includes being dilated, so we can check the optic nerve and evaluate your retinal health. Day-to-day lifestyle changes also help with maintaining eye health, especially with diabetes. This means monitoring your blood sugar and working with your endocrinologist on managing your numbers.
Your primary care physician should keep a close eye on your blood pressure, and, if it’s high, work with you on lowering it. Aim to maintain your cholesterol within healthy ranges. With any problems that arise, make sure to contact your healthcare team quickly.