Diabetes can damage eye blood vessels silently, eye specialist warns

People living with diabetes could suffer damage to their eyes long before experiencing changes in their vision, raising the risk of permanent blindness if complications go undetected and untreated, an eye specialist has warned.

Dr Rilwan Adan, Head of the Diabetes Care Centre at Lions SightFirst Eye Hospital, said high blood sugar can quietly damage the small blood vessels that supply the retina, leaving patients vulnerable to serious eye problems even when they feel healthy.

She cautioned that diabetes affects more than blood sugar levels, as the condition can also harm the eyes, kidneys and heart without causing obvious symptoms in its early stages. As a result, some patients only discover they have complications when their vision becomes blurred or other problems begin to affect their daily lives.

Speaking on Radio Generation on Thursday, Adan called for greater public awareness of the effects of diabetes on eye health, urging people to seek medical checks before noticeable symptoms develop.

“Diabetes as a metabolic disease is essentially a silent disease. There are no overt symptoms, pain, or something that can make a patient run to the doctor or the hospital. The changes that happen in the body occur silently without you having any symptoms,” Adan said.

She explained that prolonged periods of high blood sugar can damage the tiny blood vessels that carry oxygen and nutrients to the retina, the light-sensitive layer at the back of the eye responsible for receiving visual information.

The retina depends on a steady supply of blood to function properly. When diabetes damages the vessels supplying it, they may leak blood or fluid, become blocked or develop abnormal new vessels, changes that can interfere with sight.

This damage can lead to diabetic retinopathy, one of the major eye complications associated with diabetes. If the condition progresses without treatment, it can cause serious vision problems and permanent sight loss.

“Diabetes commonly affects the retina, the light-sensitive tissue at the back of the eye that contains rods and cones. Because diabetes damages blood vessels, it can interfere with the supply of oxygen and nutrients to the retina, affecting vision,” she said.

Adan also warned that blurred vision may be the first sign that a person has diabetes, particularly among those who have not been diagnosed or whose condition is not properly managed.

She said eye hospitals receive patients who believe their problem is limited to their eyesight, only for medical assessments to reveal that an underlying condition, such as diabetes, may be contributing to the problem.

“Most of the time, patients end up at the eye hospital with blurry vision, and blurry vision is a common symptom of diabetes. That is why I am at the eye hospital, because we get a lot of our patients walking in thinking that it is the eye that has brought them to the hospital, when in an actual sense there is an underlying condition, which is diabetes, that needs to be taken care of,” she explained.

The specialist urged people not to wait for blurred vision, pain or other physical changes before seeking medical attention, noting that the disease can cause damage even when a patient feels well.

She encouraged people at increased risk of diabetes to undergo medical assessments, including blood sugar tests, to establish whether they have the condition and seek appropriate care where necessary.

Another useful test is glycated haemoglobin, commonly known as HbA1c, which measures average blood sugar levels over approximately three months. The test provides a broader picture of a person's blood sugar control and can help healthcare providers assess how well diabetes is being managed.

Beyond diabetic retinopathy, Adan said people living with diabetes are also at increased risk of other eye conditions, including glaucoma and cataracts.

Glaucoma damages the optic nerve, which carries visual information from the eye to the brain, and can lead to permanent vision loss. Cataracts, meanwhile, develop when the eye's natural lens becomes cloudy, making it harder to see clearly.

Although glaucoma and cataracts differ from diabetic retinopathy, their association with diabetes makes regular eye examinations important for people living with the condition.

Adan further linked diabetes-related eye damage to kidney complications, explaining that both organs can be affected through similar processes involving damage to blood vessels.

She warned that patients with diabetes-related kidney disease should be particularly alert to possible eye problems, even if they have not noticed any changes in their sight.

“The damage is actually quite concomitant. When we have a patient who is having kidney disease and has diabetes, most likely, or rather, almost always, the eye is also affected because it is the same mechanism that causes the damage,” she added.

Her remarks highlight the need for people with diabetes to pay attention to their overall health rather than focusing only on blood sugar levels or seeking treatment when symptoms appear.

Regular eye examinations, routine blood sugar monitoring and proper management of diabetes can help identify complications early and reduce the risk of avoidable vision loss.

People already diagnosed with diabetes are encouraged to follow their healthcare providers' advice on eye screening, even when they can see clearly, as the absence of noticeable symptoms does not necessarily mean that damage has not begun.