What an eye exam catches besides your prescription

Most people book an eye exam because reading has become harder or their glasses feel wrong. That is a good reason to go, but it undersells what the appointment does. The back of the eye is the one place a clinician can look directly at small blood vessels and at nerve tissue without any imaging at all — which makes it a window onto conditions that have nothing to do with how well you see.

What the exam can pick up early

• Glaucoma. Damages peripheral vision so gradually that people often do not notice until a great deal is lost. It is detected by measuring eye pressure and examining the optic nerve — and treatment protects the sight you still have.
• Diabetic retinopathy. Diabetes damages the small vessels of the retina, often before vision changes. Diabetes Canada recommends regular eye examinations for anyone living with diabetes, because treatment works far better when started early.
• High blood pressure. Sustained high pressure leaves visible changes in the retinal vessels, sometimes the first objective sign anyone has seen.
• Age-related macular degeneration. Affects central vision — reading, faces — and has treatments that work better the earlier they begin.
• Cataracts and dry eye, which are common, very treatable, and easy to dismiss as ordinary ageing.

What the public plan pays for, using Ontario as the example

In Ontario, OHIP covers a routine eye examination once a year for people 19 and under and 65 and over. Adults aged 20 to 64 usually pay privately — unless they have a medical condition affecting the eyes, such as diabetes or glaucoma, which makes the exam covered at any age. If you have diabetes, say so when you book: people frequently pay out of pocket for an exam they were entitled to.

How often

For healthy adults aged 20 to 64, optometrists generally suggest every two years, and annually from 65. More often if you have diabetes, a family history of glaucoma, or notice a change. Children should be examined before starting school — a child with one weaker eye will rarely mention it, because to them it has always looked that way.

See someone the same day if…

You have a sudden loss of vision, a curtain or shadow across your field of view, a sudden shower of new floaters or flashes, eye pain with nausea or halos around lights, or an injury to the eye. These can be emergencies, and delay costs sight.

Sources

• Canadian Association of Optometrists — Eye health
• Ontario — Eye care coverage under OHIP
• Diabetes Canada — Eye damage
• Canadian Ophthalmological Society — Glaucoma