Or you’ll go blind?

Almost exactly one year ago, my glasses got broken. I went to a nice optometrist, had an eye exam, and got new glasses.  Apart from my recurring surprise that the lenses have to come all the way from Australia everything was fine. I’ve now had five emails telling me that my next eye exam is “due”, that this sort of regular checkup is “very important” and that it enables the “early detection of a number of eye health problems … making successful treatment more likely”.

The New Zealand medical guidelines for someone in my situation suggest that I need an eye exam at least once every five years, primarily to detect glaucoma. The Australian guidelines (PDF) are similar, but recommend starting at 50. In the US, where they really like screening, the American Academy of Ophthalmology says eye exams every 2-4 years.

That’s a bit different from what optometrists will tell you. The American Optometric Association says ‘at least every two years’ — though they don’t explain their evidence base for this — and the main NZ chains agree. One interesting exception is the College of Optometrists, in the UK, which recommends that you wait a minimum of two years if there isn’t any special reason for more frequent examination.

It’s quite hard to work out optimal screening frequency, but it does look here as though the people who describe how have they tried to consider costs and benefits carefully come up with longer intervals than people who don’t.