Can an eye test detect diabetes?

Short answer – yes! When attending an eye test the optometrist will not only advise you on whether you need glasses but will also do a health check.

Many systemic conditions like diabetes can be seen to affect the eyes. However, it is very important to remember that secondary changes in the eye usually occur when the underlying condition is more established, rather than in its early stages. A healthy eye does not necessarily mean that you do not suffer from an underlying systemic condition, but the best guarantee is to see your GP for the necessary health tests.

Diabetes is one of the most common systemic conditions that can affect the eyes and can be observed when checking the health of eyes in a number of ways.

Diabetic retinopathy

This is the main secondary effect observed in diabetics and is due to changes seen on the retina (the retina is the light-sensitive layer of cells at the back of the eye). From here light is converted to electrical signals which then go to the brain to produce the images that we see.

The retina is supplied by a network of blood vessels and is the only part of the body where we get a direct view of this circulation. As high blood sugar in diabetes causes damage to these blood vessels this can lead to fluid leak or haemorrhages. Early stages of diabetic retinopathy do not often affect the vision and so can progress unnoticed. It is thus very important that all diabetics have an annual diabetic screening so early detection, timely treatment and controlling your diabetes (through medication, healthy diet, regular exercise and normal body weight) can prevent or delay further progression which can otherwise eventually lead to loss of vision.

Diabetic macular oedema

This is usually due to progression of diabetic retinopathy and is due to the accumulation of fluid in the macula. The macula is the part of the retina that controls our most detailed vision abilities hence any changes in this region will have a significant impact on our vision.

Cataracts

This is a clouding of the crystalline lens in the eye (our natural lens) and diabetic patients are more likely to develop cataracts changes earlier than those who are not diabetic.

Glaucoma

This is where there is damage to the nerve fibres that connect the eye to the brain and diabetes again has been shown to increase the risk of developing glaucoma.

As outlined above, diabetes does have many secondary effects on the eye but again it is important to remember that a healthy retina DOES NOT mean you do not have diabetes and the only conclusive answer is for you to see your GP who will do the necessary tests.