Diabetes and eye health

Diabetes affects the whole body, and the eyes are no exception. High blood sugar levels can damage the small blood vessels at the back of the eye, the lens and the optic nerve. The good news is that most diabetes-related eye problems can be prevented or treated if they are detected early. Good blood sugar control and regular eye examinations are the two most important things you can do to protect your sight.

Diabetic retinopathy

Diabetic retinopathy is the most common eye complication of diabetes. It happens when high blood sugar damages the tiny blood vessels in the retina, the light-sensitive layer at the back of the eye. In the early stages, there may be no symptoms, but the changes can be seen on a retinal examination. If left untreated, diabetic retinopathy can cause bleeding, swelling and scarring, leading to permanent vision loss.

There are different stages. Background retinopathy is the earliest stage and may not affect vision. Maculopathy affects the central retina and can reduce detailed vision. Proliferative retinopathy involves the growth of abnormal new blood vessels, which can bleed and cause serious sight loss. Treatment options include laser therapy, injections into the eye and surgery in advanced cases.

Diabetic macular oedema

Diabetic macular oedema is swelling of the central retina, caused by leaking blood vessels. It can blur or distort central vision, making tasks like reading and recognising faces difficult. It is often treated with anti-VEGF injections, which reduce leakage and swelling. Early treatment gives the best chance of preserving central vision.

Cataracts and diabetes

People with diabetes tend to develop cataracts at a younger age, and the cataracts may progress more quickly. High blood sugar can cause the lens to swell and become cloudy. Cataract surgery is generally safe in people with diabetes, but it is important that the retina is healthy and the blood sugar is well controlled before the operation.

Glaucoma and diabetes

Diabetes increases the risk of developing glaucoma, a condition where the optic nerve is damaged, often by raised pressure in the eye. People with diabetes are also more likely to develop neovascular glaucoma, a severe form caused by abnormal blood vessel growth. Regular eye checks help detect glaucoma early, before vision is lost.

Why regular eye checks matter

Many diabetes-related eye conditions cause no symptoms in the early stages. By the time vision is affected, the damage may already be advanced. Regular retinal screening, usually once a year, can pick up changes before they threaten sight. These screenings are different from a standard sight test and are usually offered free to people with diabetes in the UK.

If you notice any new symptoms, such as blurred vision, floaters, flashes, or sudden vision loss, you should seek urgent eye care rather than waiting for your next screening appointment.

Controlling your blood sugar

The best way to protect your eyes from diabetes is to keep your blood sugar, blood pressure and cholesterol levels well controlled. High blood pressure and high cholesterol can worsen retinopathy, so managing these alongside glucose is important. Stopping smoking, maintaining a healthy weight, taking regular exercise and following your diabetes treatment plan all help reduce the risk of eye complications.

Laser eye surgery and diabetes

Diabetes is not an automatic barrier to laser eye surgery, but it does require extra caution. Your prescription must be stable, your blood sugar well controlled, and your retina must be healthy. If you have diabetic retinopathy or significant dry eye, laser surgery may not be the best option. Alternatives such as implantable collamer lenses or refractive lens exchange may be more appropriate in some cases.

What to do if you have diabetes

If you have diabetes, make sure you attend every retinal screening appointment and have a full eye examination if you notice any changes. Bring your latest HbA1c result and a list of medications to any eye consultation. If you are considering surgery, tell your ophthalmologist about your diabetes from the start so they can plan the safest approach.

Next steps

If you have diabetes and have not had a retinal check in the last year, book one now. If you are concerned about your vision or want to discuss treatment options, arrange a comprehensive eye examination. Early detection and good diabetes control are the most powerful ways to keep your sight safe.