If you have diabetes, you probably already check your blood sugar and visit your physician regularly. But there is one more check-up that is easy to forget — and it can protect your eyesight: a yearly diabetic eye examination.
Diabetes can quietly damage the eyes for years before you notice anything wrong. This article explains why, what a diabetic eye check involves, and how problems are treated when they are found.
How does diabetes affect the eyes?
High blood sugar over time damages small blood vessels throughout the body — including the tiny vessels in the retina, the light-sensitive layer at the back of the eye that works like the film in a camera.
This damage is called diabetic retinopathy. It can affect the eye in two main ways:
- Leaking vessels. Damaged vessels leak fluid and blood into the retina. When fluid collects in the macula — the small central area of the retina you use for reading and recognising faces — it causes swelling called diabetic macular oedema, which blurs central vision.
- New, fragile vessels. When parts of the retina are starved of oxygen, the eye grows new blood vessels. These are weak and can bleed into the eye or pull on the retina, which can lead to serious loss of vision. This stage is called proliferative diabetic retinopathy.
People with diabetes are also more likely to develop cataract earlier, and have a higher risk of glaucoma.
Why you can't wait for symptoms
In its early stages, diabetic retinopathy usually causes no symptoms at all. Your vision can seem perfectly normal while damage is building up inside the eye. By the time vision becomes blurred, the disease may already be advanced.
That is why a regular eye check is so important. Finding diabetic retinopathy early — before it affects your sight — gives treatment the best chance of protecting your vision.
Seek an eye check sooner than planned if you notice:
- blurred or fluctuating vision
- dark spots, threads or "cobwebs" floating in your vision (floaters)
- patches of missing vision
- difficulty seeing at night
Who needs a diabetic eye check, and how often?
- Everyone with diabetes — type 1 or type 2 — should have a dilated eye examination at least once a year, even if vision is fine.
- Your doctor may advise more frequent checks if retinopathy has already been found, if your blood sugar or blood pressure is poorly controlled, or during pregnancy.
- If you have just been diagnosed with type 2 diabetes, have your eyes checked soon — the disease may have been present for some time before diagnosis.
What happens at a diabetic eye check?
A diabetic eye examination is simple and takes a few steps:
- Vision test — reading letters on a chart.
- Eye pressure check — to screen for glaucoma.
- Dilating drops — these widen the pupil so the doctor can see the whole retina clearly. They take about 20–30 minutes to work.
- Retina examination — the doctor looks at the back of the eye with a special lens and light.
- OCT scan, if needed — an OCT scan takes detailed cross-section pictures of the retina, showing swelling in the macula that cannot always be seen in a normal examination. Nothing touches your eye.
The dilating drops blur your vision and make you sensitive to light for a few hours. Bring someone with you, and do not drive home. Sunglasses help on the way back.
How is diabetic eye disease treated?
Treatment depends on what the examination finds. You can read more on our diabetic retinopathy treatment page.
- Early changes may only need closer monitoring and better control of blood sugar, blood pressure and cholesterol, working with your physician.
- Macular oedema (swelling at the centre of vision) is commonly treated with injections of medicine into the eye. These reduce leakage and swelling, and are usually given as a series.
- Abnormal new blood vessels are commonly treated with PRP laser, which helps shrink the vessels and lowers the risk of bleeding and retinal detachment.
- Advanced disease with bleeding inside the eye or a detached retina may need surgery.
Treatment aims to protect the vision you have. Damage that has already happened may not fully recover, which is another reason why early detection matters so much.
What you can do to protect your eyes
- Keep your blood sugar in your target range. Ask your physician what your HbA1c target is.
- Control your blood pressure and cholesterol. Both affect the blood vessels in the eye.
- Don't smoke. Smoking further damages blood vessels.
- Take your medicines regularly and keep up with your physician's check-ups.
- Have your eyes checked every year — put it in your diary alongside your other diabetes check-ups.
A note for families
Many people with diabetes — especially older family members — delay eye checks because they "can still see fine". If someone in your family has diabetes, encourage them to have a yearly eye examination and offer to go with them. It is one of the simplest ways to help them keep their sight.
Book a diabetic eye check
If you or a family member has diabetes and has not had an eye check in the last year, now is a good time. Our eye doctors can examine the retina and explain the results in plain language.
Medically reviewed by Dr. Sweta Patro