Diabetes and your eyes: How often should you have a check-up?

Why can diabetes damage the eyes?

Persistently elevated blood glucose levels can damage small blood vessels. In the retina, vessels may become leaky, small haemorrhages may develop, or new, fragile vessels may grow. If the changes affect the macula—the area responsible for sharp central vision—fluid can build up there. [1][2]

The difficulty is that early retinal changes often cause no symptoms. Someone may still see well despite having changes that already require treatment. The aim of the examination is to detect damage before permanent sight is lost. [1][2]

How often should your eyes be checked?

People with type 2 diabetes are advised to have their first retinal examination at the time of diagnosis. For type 1 diabetes, the first retinal examination is generally recommended five years after diagnosis. Special age-based guidance applies to children; the individual starting point should be agreed with the diabetes and ophthalmology teams. [1][3][4]

If there are no known retinal changes and neither general nor ophthalmic risk factors are present, Germany’s National Disease Management Guideline recommends a two-year interval. If the risk is higher—for example because of a longer duration of diabetes, suboptimal metabolic control, high blood pressure, kidney damage, or smoking—an annual examination is generally recommended. [1][3][4]

• No retinopathy and low risk: often every 2 years
• No retinopathy but additional risks: generally once a year
• Known retinal changes: annually or considerably more often
• Pre-existing diabetes and pregnancy: examination promptly when pregnancy is confirmed and generally every three months; shorter intervals may be necessary if retinopathy develops or progresses

What happens during the eye examination?

The consultation covers how long you have had diabetes, your current glucose control, blood pressure, kidney disease, medication, and any visual symptoms. This is usually followed by a visual acuity test, a slit-lamp examination, and assessment of the back of the eye. [2][3]

To obtain a good view of the retina and macula, the pupils are usually dilated with eye drops. Glare and blurred near vision can last for several hours afterwards. Do not drive, cycle or operate machinery until your vision has returned to normal, and arrange your journey home accordingly. If anything unusual is found, additional tests such as OCT, fundus photography or fluorescein angiography may be needed. They are not automatically part of every basic check-up. [3][4]

Is a red eye associated with diabetes?

Diabetic retinopathy affects the retina inside the eye. Redness on the surface of the eye is therefore not a typical early sign of this condition. Redness may be caused, for example, by dry eye, inflammation of the eyelid margins, an allergy, conjunctivitis or irritation of the cornea.

People with diabetes may also be more likely to develop problems affecting the eyelids and ocular surface. Even so, redness should not automatically be attributed to diabetes. Its cause and urgency need to be assessed in light of any accompanying symptoms. [2]

What can people with diabetes do themselves?

Regular eye examinations are not a substitute for good diabetes treatment—and good blood glucose control is not a substitute for an eye examination. Both are important. Individual target values should be agreed with your diabetes care team. [1][2]

• Have blood glucose, blood pressure, and blood lipids managed according to your personal treatment plan
• Do not smoke, or seek support to stop smoking
• Attend eye appointments even if you have no visual symptoms
• Discuss eye examination intervals if your diabetes treatment changes rapidly or if you are pregnant
• Do not wait until your next routine appointment if you develop new visual symptoms

Which changes in vision are urgent?

Blurred or distorted vision, dark patches, and increasing difficulty reading can indicate advanced changes. A sudden shower of black specks, soot-like floaters, flashes of light, a dark curtain, or severe loss of vision may be warning signs of bleeding or retinal detachment. [2][3][4]