Eye tests can determine other diseases

If you have perfect vision, you may think you don’t need regular eye examinations. Yet an eye test may save your sight — or highlight a health condition completely unrelated to your vision.

“The eye is the only transparent part of your body,” says Dr Susan Blakeney, Clinical Adviser to the College of Optometrists. “So it’s a way of seeing inside a patient. For example, tiny blood vessels in the retina are visible which, if leaking, can be a sign of diabetes or high-blood-pressure.”

A sight test can also spot glaucoma, which may not present physical symptoms until it is too late. “Most glaucoma is painless,” says Dr Blakeney. “A person with the condition slowly loses their vision in patches — and won’t get that vision back.”

"A sight test can also spot glaucoma, which may not present physical symptoms until it is too late."

Research has shown that white people over 40 are at greater risk of glaucoma, but Afro-Caribbean people are at risk from a much younger age. Other conditions that can be discovered by a sight test include high cholesterol, macular degeneration and even brain tumours.

The process of sight tests

There are two parts to an eye examination. One ensures that the patient is able to see as clearly and as comfortably as possible; the other checks eye health. Whenever the practitioner checks whether you need spectacles he or she is legally required to also check your eye health.

“The law regulates that only optometrists and doctors are permitted to perform sight tests,” says Dr Blakeney, “and that, when they do, both internal and external examinations of the eye must be made, by whatever means appropriate; plus other tests that appear to be necessary for the purpose of detecting signs of abnormality or disease.”

Children susceptible to lazy eye

These may include eye pressure measurements and/or a visual field test. The examination can take 20 or 30 minutes, depending on the age of the patient and how clinically complex their needs are. It’s not just adults who benefit from regular eye tests. 

The College of Optometrists recommends that children aged 4-5 who do not have access to vision screening at primary school have an eye examination with an optometrist. “If a child has a condition which affects one eye, it may lead to that eye becoming ‘lazy’,” says Dr Blakeney. “This can be treated if it’s caught early; but it’s much more difficult — and may not be successful — if diagnosed later.”