(Captions for photos) Eye specialist Wong Tien Yin, who is the new head of the Singapore Eye Research Institute, says the organization has submitted a proposal to the Health Ministry to obtain images of damage caused by diabetes to the retina from polyclinics and eye imaging centres. ST PHOTO: CAROLINE CHIA

Narrow blood vessels in retina could be a sign of kidney failure

THE eyes can be a window to a person’s health.

Eye specialist Wong Tien Yin has found that the blood vessels in the retina – the light-sensitive tissue at the back of the eye – can sound the alarm on the risk of diabetes and heart and kidney failure.

His latest work has identified the precise blood vessels in the eye linked to chronic kidney failure: People with narrowed vessels have protein in their urine, which is a sign of kidney failure.

So, doctors can take an image of the retina to get a glimpse of what is wrong deep within the body, in a non-invasive way.

Diabetics are the main victims of kidney failure.

Said diabetics specialist Tan Chee Eng, who is from Gleneagles Medical Centre: “In diabetes, the same mechanism that affects the eyes also affects the kidney. So if there is damage to the eye, there is usually damage to the kidney as well.”

Imaging the eye to check for kidney damage in diabetic patients would complement current tests which check for leakage of proteins in their urine to determine such damage, he said.

Scientists have, for about 20 years now, suspected that damaged tiny blood vessels in certain spots of the eye signaled kidney disease. But they were unsure exactly which type of blood vessels to look out for.

Since the vessels in the eye and blood are very similar, narrow eye blood vessels mean that blood vessels in the kidney are likely to be narrow too. Narrow vessels mean less oxygen and nutrients supplied, leading to organ damage.

Using images taken of almost 3,300 randomly selected people, Professor Wong and his team measured the blood vessels and discovered that the micro blood vessels which point to kidney damage are arterioles, which carry oxygen and nutrient-rich blood from the heart to the rest of the body.

The narrower the vessels, the greater the damage done, they found.

Yesterday, Prof Wong won the Outstanding Researcher Award from the National University of Singapore for his work on using the eye as a model to study human diseases.
Prof Wong, 41, who is also the new head of the Singapore Eye Research Institute (Seri), wants to carry out more programmes that have a direct impact on public health, including a critical large scale project on blindness caused by diabetes.

Diabetes, which affects about 13 per cent of adults in Singapore, is the most common cause of blindness here.

The disease causes blood vessels in the retina to be damaged, cutting off blood flow and causing blindness.

But many patients, whose eyes have been damaged by diabetes, may not know it until it is too late to save their vision because they can still see just as well very late into the disease.

The institute has submitted a proposal to the Health Ministry to work with polyclinics and eye imaging centres, which will send Seri images of damage caused by diabetes to the retina – a condition known as diabetic retinopathy.

Trained readers at the institute can then use its equipment to pick out the damage and refer the affected patients to eye specialists, said Prof Wong.

What he also wants to do is to build a national database to examine the eyes and retina, so that the disease can be picked up and treated earlier.

National University Hospital eye specialist Caroline Chee said such a database would help streamline the process of diabetic screening.

“The purpose of having a national database is to make the screening process more accurate in picking up the people who have potentially blinding diabetic eye diseases,” said Dr Chee, who specializes in the retina.

Monitoring the vision of diabetic patients is important, say doctors.

“Loss of vision due to diabetes also alerts the doctor to the fact that this patient has a high risk of having other complications of diabetes as well such as kidney failure, stroke, heart disease,” Dr Chee pointed out.

Polyclinics here have also welcomed Seri’s move.

The director of clinical and corporate services at the SingHealth group of polyclinics, Dr Adrian Ee, said that retinal images of diabetic patients are already being taken at the polyclinics.

Patients with abnormal readings are referred to eye specialists.

“Having the images read by a different team would enable our polyclinic doctors to spend more time on patient care,” said Dr Ee.

wycin@sph.com.sg