When we think eye tests we generally think new prescription glasses. But a comprehensive eye test can be much more than that - a peek into your peepers can tell a whole lot about your overall health. This is because the eyes are the only part of the body where there is an unobstructed view of blood vessels and nerves, and often, a disease can first be detected through an eye test.
Eyes should be examined every two years, regardless of whether eyesight is perfect, though some people may need eye tests more frequently. Besides eye diseases that can lead to vision loss, such as glaucoma or macular degeneration, eye tests can also pinpoint other health conditions.
High blood pressure
An eye test can spot damage to the blood vessels at the back of the eye that results from high blood pressure. This can include the thickening, narrowing or haemorrhaging of blood vessels or may be seen as bends, kinks or tears. Picking up high blood pressure can help avert heart attacks and strokes.
High levels of cholesterol in the blood can cause blockages in the eye's blood vessels and can lead to blind spots in vision. Lumps of cholesterol moving through the vessels can be seen in an eye test and are an indication of cardiovascular disease.
Cancer of the eye, also known as ocular melanoma, develops in the cells that make pigment in the eye and affects the choroid layer, between the retina and white of the eye. An eye test will detect a large, raised surface in this area. The earlier this cancer is detected the better as it is aggressive and can spread to the brain.
Although rare, brain tumours can be detected by an eye test. For instance, the pressure of a tumour, particularly in the pituitary gland, will result in the swelling of the optic nerve or optic disc or there may be changes in the field of vision. An eye test can often pick up these abnormalities at an early stage before the onset of other symptoms.
In diabetes, high blood-glucose levels can damage blood vessels in the retina of the eye, causing them to leak or bleed, which can lead to vision loss. This damage can be picked up in an eye test.
Multiple sclerosis (MS)
MS is a degenerative disease of the nervous system and visual defect, including blurred vision and difficulty focusing, are often one of the symptoms. These visual defects result from optic neuritis, inflammation of the optic nerve, which can be picked up by an eye test. However, not everyone with optic neuritis will go on to develop MS.
Rheumatoid arthritis (RA)
This autoimmune disease is characterised by inflammation of the joints but the inflammation can also affect the eyes, particularly the whites of the eye and the cornea. Cataracts are also a possible sign of RA.