Page contents
- How does diabetes affect the eyes?
- Why have a check-up even when you see well?
- Who is at higher risk of eye damage?
- How often do you need a diabetic eye exam?
- What does diabetic retinopathy screening involve?
- What happens if changes are found?
- What you can do for your eyes
- When to see an ophthalmologist urgently
- Frequently Asked Questions about Diabetic Eye Exams
Diabetes and the eyes are closely linked, because high blood sugar levels slowly damage the small blood vessels of the retina. Anyone with diabetes usually needs a diabetic eye exam with dilated fundoscopy at least every one to two years, and more often if changes are already present, even if their vision seems normal.
How does diabetes affect the eyes?
The retina is the light-sensitive tissue at the back of the eye and is nourished by a dense network of fine blood vessels. Over the years, raised blood sugar damages the walls of these vessels: they leak fluid and blood, become blocked or form microaneurysms. This is diabetic retinopathy, one of the most common causes of serious sight loss in people of working age.
Diabetes is also linked to other eye problems:
- Diabetic macular oedema: a build-up of fluid in the centre of the retina, which blurs central vision. It can occur at any stage of retinopathy.
- Cataract: often develops earlier in people with diabetes.
- Glaucoma: the risk is increased, particularly for a severe form linked to the growth of new blood vessels on the iris.
- Fluctuations in vision: when blood sugar rises and falls sharply, vision can blur temporarily, because the lens of the eye changes for a while.
Why have a check-up even when you see well?
In its early stages, diabetic retinopathy causes no symptoms at all. Vision can remain excellent while there are already haemorrhages or leaks in the fundus. By the time the patient notices blurring, the damage has often progressed. Regular screening detects the changes at the stage when treatment has the best chance of protecting vision.
This is why international guidelines, from the American Academy of Ophthalmology to the UK’s NHS, treat the eye examination as an integral part of diabetes care, just like blood tests.
Who is at higher risk of eye damage?
Anyone with diabetes, type 1 or type 2, can develop retinopathy. However, certain factors significantly increase the likelihood and the speed of progression:
- Duration of diabetes: the more years the disease has been present, the higher the risk. After 15 to 20 years of diabetes, a large proportion of patients have some degree of change.
- Long-term poorly controlled blood sugar: glycated haemoglobin (HbA1c) is one of the strongest predictors.
- High blood pressure and raised lipids: these put additional strain on the blood vessels of the retina.
- Kidney disease: diabetic nephropathy often occurs together with retinopathy.
- Pregnancy: in women with pre-existing diabetes, retinopathy can worsen during pregnancy.
- Smoking: it damages blood vessels and worsens the overall picture.
It is worth noting that a very rapid and sharp improvement in blood sugar can, in some patients, be accompanied by a temporary worsening in the fundus. This does not mean that control should be delayed, but that your ophthalmologist should be aware of any significant change in your treatment.
How often do you need a diabetic eye exam?
The frequency depends on the type of diabetes, how long you have had it, blood sugar control and, above all, what the ophthalmologist finds at each examination. The table summarises general guidance from international guidelines. Your ophthalmologist will set the exact schedule for you.
| Situation | When a check-up is usually recommended |
|---|---|
| Type 2 diabetes, at diagnosis | First check-up at diagnosis or shortly afterwards, because the disease may have been present for years before it was diagnosed |
| Type 1 diabetes in adults | First check-up usually within the first 5 years after diagnosis |
| Children and teenagers with type 1 diabetes | Usually from adolescence or after a few years of diabetes, in consultation with the paediatric endocrinologist |
| No retinopathy, good control | Every 1 to 2 years |
| Mild non-proliferative retinopathy | Usually every 12 months or more often, at the doctor’s discretion |
| Moderate non-proliferative retinopathy | Usually every 6 to 12 months |
| Severe non-proliferative or proliferative retinopathy | Every few months, often combined with treatment |
| Diabetic macular oedema | Close monitoring, often every few weeks or months during treatment |
| Pregnancy with pre-existing diabetes | Before conception or in the first trimester, then every trimester and for up to one year after delivery |
| Gestational diabetes | Specific retinal screening is not usually needed during pregnancy |
If your blood sugar or blood pressure is poorly controlled, if your diabetes treatment is being intensified, or if you also have kidney disease, your ophthalmologist may recommend more frequent check-ups.
What does diabetic retinopathy screening involve?
Screening for diabetic retinopathy is simple and is carried out in the clinic. It usually includes:
- Measurement of visual acuity with your glasses on.
- Measurement of intraocular pressure, to check for glaucoma.
- Slit lamp examination of the front of the eye and the lens.
- Fundoscopy with pupil dilation (mydriasis): the drops enlarge the pupil for a few hours so that the whole retina can be seen. For this reason, it is best not to drive after the examination.
Additional imaging tests
Fundus photography records the appearance of the retina, so that changes can be compared accurately from one examination to the next. Optical coherence tomography (OCT) provides cross-sectional images of the macula and detects even a small build-up of fluid before the patient notices it. It is a key test for diagnosing and monitoring diabetic maculopathy. Both tests are quick and do not involve touching the eye.
What happens if changes are found?
In the mild stages, closer monitoring and better diabetes control are usually enough. When macular oedema or proliferative retinopathy develops, there are effective treatments, such as intravitreal injections and retinal laser. The aim is to stabilise the disease and preserve vision. Early treatment has much better results than delayed treatment.
What you can do for your eyes
- Keep your blood sugar as close as possible to the targets agreed with your diabetes specialist.
- Have your blood pressure and cholesterol checked and controlled.
- Stop smoking.
- Do not skip your yearly or two-yearly eye examination, even when “everything is fine”.
- Bring your recent blood test results and a list of your medicines to the appointment.
World Diabetes Day, on 14 November, is a good reminder to check when your last dilated eye examination was. If it has been more than two years, or you have never had one, it is time to book it.
When to see an ophthalmologist urgently
Do not wait for your scheduled check-up if you have diabetes and notice:
- sudden blurring or loss of vision,
- many new floaters or shadows drifting across your field of vision,
- a dark area or curtain over part of your field of vision,
- straight lines that look bent,
- pain and redness in the eye.
For a preventive check-up or monitoring of diabetic retinopathy, book an appointment at our clinic in Neo Psychiko, Athens.
Frequently Asked Questions about Diabetic Eye Exams
If I can see clearly, do I still need an eye check for diabetes?
Yes. In its early stages, diabetic retinopathy does not affect vision and does not cause pain. There may be haemorrhages or fluid leaking in the retina without any symptoms. Only fundoscopy and imaging tests detect them early, when treatment can best protect your vision.
Does the dilated eye examination affect my vision?
Dilating drops enlarge the pupil for a few hours. During this time, near vision is blurred and light is more uncomfortable. The effect wears off on its own the same day. It is a good idea to bring sunglasses with you and not to drive until your vision has returned to normal.
Can good blood sugar control prevent eye damage?
Good control of blood sugar, blood pressure and lipids significantly reduces the risk of retinopathy developing and getting worse, according to large clinical studies. It does not eliminate it, however. This is why regular eye examinations are needed even in patients whose diabetes is very well controlled.
Does a sight test at the optician’s cover diabetic eye screening?
A sight test for glasses checks how clearly you see, not the health of the retina. Diabetes requires a medical examination of the fundus, ideally with pupil dilation, and fundus photography or OCT where needed. This is carried out by an ophthalmologist, who can also recommend treatment if changes are found.
Questions about your case?
Dr. Skouteris will examine you at his practice in Neo Psychiko and explain your options.
Ophthalmic surgeon trained at the John Radcliffe University Hospital in Oxford and Fellow of the European Board of Ophthalmology (FEBO).
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