How Diabetes Can Affect the Eyes

If you’re living with diabetes, your eyes deserve the same regular attention as your blood sugar. Diabetic eye disease refers to a group of conditions, and anyone with type 1 or type 2 diabetes can develop one. The longer you have lived with diabetes, the higher your risk. The good news is that these conditions are far more treatable than they were a generation ago, and the earlier they are found, the more we can do.

Below, our retina eye care doctors explain how diabetes affects the eye, which conditions to watch for, how they are treated today, and what you can do to protect your vision.

H2: Diabetes and Its Effect on Your Eyes

Diabetes begins with insulin, the hormone that allows blood sugar (glucose) to pass from the blood into your cells to be used for energy. But when your body cannot process insulin well (Type 2 diabetes), or it stops producing insulin entirely (Type 1 diabetes), that’s when the problems start.

Over time, that excess sugar damages the body’s smallest blood vessels, including those in the kidneys, the nerves, and the eyes. The retina – the light-sensitive tissue lining the back of the eye that works something like the film in a camera – depends on a dense network of tiny vessels. When those vessels are damaged, they can leak fluid or blood into the retina, close off entirely and starve the tissue of oxygen, or trigger the growth of fragile new vessels. Any of these can blur or block vision.

One point matters more than any other: this damage usually begins silently. Most people have no symptoms at all in the early stages, which is exactly when treatment works best. By the time vision changes, the disease is often well established. A yearly dilated eye exam is how we find it first.

Common Diabetic Eye Diseases

Early on, you may notice nothing at all. As diabetic eye disease progresses, symptoms can include blurred or fluctuating vision, dark floating spots, trouble reading or recognizing faces across a room, difficulty driving at night, or sudden loss of vision. Below are the conditions we see most often.

Diabetic Retinopathy

Diabetic retinopathy (DR) is damage to the blood vessels of the retina, and it is the most common diabetic eye disease. It is also the leading cause of new blindness among working-age adults in the United States – and one of the most preventable.
In the earlier (nonproliferative) stage, retinal vessels weaken, develop tiny bulges, and begin to leak fluid, blood, and fatty deposits into the retina. Many people see normally at this stage, which is why it is so often found on a routine exam rather than because of a symptom.

In the advanced (proliferative) stage, enough vessels have closed off that the retina is starved of oxygen and responds by growing fragile new blood vessels. These vessels bleed easily into the vitreous gel that fills the eye, which is when people notice dark floating spots, streaks resembling cobwebs, or a sudden drop in vision. A small bleed may clear on its own, but its appearance signals advanced disease and should be evaluated promptly. If proliferative disease goes untreated, scar tissue forms on the surface of the retina and contracts, pulling the retina out of position. This is called a tractional retinal detachment, and it usually requires surgery.

Diabetic Macular Edema

The macula is the small central portion of the retina responsible for sharp, straight-ahead vision – reading, recognizing faces, seeing road signs. When damaged vessels leak fluid into the macula, it swells. This is diabetic macular edema (DME), and it is the most common cause of vision loss in people with diabetes.

DME typically causes central blurring, dimmed or washed-out color, or straight lines that look wavy or bent. It can develop at any stage of retinopathy, including early stages, which is another reason routine exams matter. We detect and monitor it with optical coherence tomography (OCT), a painless scan that takes only seconds and produces a cross-sectional view of the retina detailed enough to measure swelling in microns. DME responds well to treatment, and results are best when it is treated before vision has been reduced for a long period.

Cataracts

A cataract is a clouding of the eye’s natural lens, often described as looking through a foggy or frosted window. Everyone develops cataracts with age, but people with diabetes tend to develop them more often and at a younger age. High blood sugar alters the chemistry inside the lens, causing it to take on fluid and gradually lose its clarity. The clouding forms within the lens itself rather than as a film on its surface.

The only treatment is surgery, and surgeons generally wait until the cataract is interfering with daily life. Most people see dramatically better after cataract surgery. If you have diabetes, your surgeon will want your retina evaluated before surgery is scheduled. Cataract surgery can worsen macular swelling, so it is best to identify any edema – and often treat it – beforehand. It is also common for a cataract to hide retinopathy from view, so the retina deserves a careful look once the lens is clear.

Glaucoma

There are multiple types of glaucoma. All of them damage the optic nerve, the cable that carries images from the eye to the brain. Glaucoma is usually, though not always, associated with elevated pressure inside the eye, and most forms cause no symptoms until vision has already been permanently lost.

People living with diabetes are twice as likely to develop open-angle glaucoma, the most common type. There is no way to truly prevent it, but early detection and treatment can slow its progression and preserve sight.

Advanced diabetic retinopathy can also cause a less common but far more aggressive form called neovascular glaucoma. When the retina is severely oxygen-starved, abnormal new vessels can grow on the iris and block the eye’s natural drainage system, leading to elevated eye pressure, often causing pain and rapid vision loss. This is an urgent problem, and it is often treated by both a retina and glaucoma specialist alongside the underlying retinopathy that caused it.

Blurred Vision That Comes and Goes

Not every vision change from diabetes is permanent. When blood sugar rises or falls quickly, the lens of the eye absorbs fluid and changes shape, which can blur vision for hours or even days. This usually settles once glucose levels stabilize. It is also why we recommend waiting until your blood sugar has been steady before updating a glasses prescription – otherwise the new lenses may be wrong within a week. Mention this pattern to your doctor, since it can be an early sign that glucose control needs attention.

How to Lower Your Risk of Diabetic Eye Disease

With over 40 million Americans affected by diabetes and more than one in four unaware they even have it, it’s no wonder prevention slips under the radar. While diabetic eye disease cannot be prevented with certainty, you can meaningfully lower your risk and dramatically improve your odds of keeping your vision.

• Manage Blood Sugar: Sustained high glucose is what damages retinal vessels over time. Work with your primary care doctor or endocrinologist on targets that are right for you and take medications as prescribed.
• Manage blood pressure and cholesterol, too. These are just as important to eye health as blood sugar and are frequently overlooked. Kidney disease and smoking also raise your risk.
• Get a dilated eye exam on the right schedule. At a comprehensive eye exam, your doctor will look for any ocular problems before they become an issue later on. A dilated retinal exam is not the same as a vision screening or a glasses check. The timing of your first exam depends on which type of diabetes you have:
  • Type 1 diabetes: a first dilated exam within five years of diagnosis.
  • Type 2 diabetes: a dilated exam at the time of diagnosis, since retinopathy may already be present before diabetes is identified.
  • After that: at least once a year, and more often if retinopathy is already present.
  • Pregnancy: if you have pre-existing type 1 or type 2 diabetes and are pregnant or planning to be, you need an exam before pregnancy or early in the first trimester and monitoring throughout, because retinopathy can progress quickly during pregnancy. Gestational diabetes that first develops during pregnancy does not carry the same risk and does not require these exams.

• Report vision changes right away: New floaters or dark spots, a curtain or shadow across your vision, distortion of straight lines, or any sudden drop or change in vision should be evaluated urgently. Do not wait for your next scheduled appointment.

How Diabetic Retinopathy and Macular Edema Are Treated Today

This is the part of the story that has changed the most. A generation ago, laser was essentially the only tool available, and the realistic goal was to slow further loss. Today, a substantial number of patients may recover vision, and treatment can reverse the severity of retinopathy itself in some cases.

• Anti-VEGF injections. These medications block the chemical signal that drives leakage and abnormal vessel growth. They are the mainstay of treatment for diabetic macular edema and for proliferative retinopathy. The injection is given in the office with numbing medication and is a relatively quick procedure. Most patients find it far easier than they expected.
• Longer-acting and sustained-release therapy. Newer options are designed to extend the interval between treatments, including a refillable implant placed in the wall of the eye that releases medication continuously over months. For the right patient, this can reduce treatment visits considerably.
• Steroid therapy. Injectable or implantable steroids are an option for macular swelling that does not respond adequately to anti-VEGF treatment.
• Laser treatment. Laser remains an important tool, particularly panretinal photocoagulation to reduce the risk of severe bleeding.
• Vitrectomy surgery. Microsurgery to remove blood that will not clear from the vitreous gel, or to peel away membranes and/or repair a tractional retinal detachment.

Advanced Retina Care

Diabetic retinopathy and diabetic macular edema are not occasional cases for us. They are a core part of what our retina service does every week, and our patients have access to the full range of current therapy without leaving the Upstate.

Our retina service is led by Dr. Adam Pflugrath, a fellowship-trained vitreoretinal surgeon who completed his fellowship at the Charles Retina Institute in Memphis, training under Dr. Steve Charles – a surgeon widely credited with developing many of the instruments and techniques that made modern retinal microsurgery possible. That training spans the entire range of diabetic eye disease, from a first injection for macular swelling through the repair of the most complex diabetic retinal detachment.

What that means for patients here:

• Diagnosis and treatment in one visit. Retinal imaging is performed on site. If we find macular swelling during your exam, we may be able to perform treatment the same day rather than scheduling you to come back.
• The full range of current therapy. Anti-VEGF injections, sustained-release and implantable drug delivery, steroid therapy, and laser – chosen for the individual patient rather than applied as a single default protocol.
• Surgical care. When surgery is needed, vitrectomy and complex diabetic retinal surgery are often performed in an outpatient surgery center rather than a hospital, and by the same surgeon who cares for you in clinic.
• Contribution to the field. Our retina provider’s work has been presented at national and international retina meetings.
• Prompt access when something changes. Sudden floaters, a shadow in your vision, or an abrupt change in sight are handled as urgent referrals rather than routine appointments.

Protect Your Vision with Ongoing Eye Care at Jervey Eye Group

Prevention is always the best treatment, and early detection is the next best thing. Most of the vision we are able to save is due to someone coming in for an evaluation prior to anything feeling wrong. Diabetes is the one eye condition where having everything under one roof genuinely matters. It can affect the retina, the lens, and the pressure inside the eye at the same time, and those problems interact with one another. Swelling in the macula changes when cataract surgery should be done. A dense cataract can hide retinopathy from view until it is removed. Treating one part of the picture without knowing what the rest of the eye is doing leads to worse results.

At Jervey Eye Group, your dilated exams, your retina care, your cataract surgery, and your glaucoma management all happen inside the same practice, with your doctors able to speak to one another directly. You are not carrying records between offices or waiting weeks for an outside referral to be scheduled. With locations across the Upstate, you can be seen close to home.

Our team at Jervey Eye Group believes in providing you with the best patient experience. If you’re ready to speak with us about your vision needs while living with diabetes, we’re here to support you!

Schedule your appointment with Jervey Eye Group, or call us at 864-458-3900.