Vision tests

Whilst at a recent near distance vision testing meeting, my eyes were opened (cringe-worthy) to the requirements for vision testing and how an individual’s vision can be very different to that of another person. One question that is often asked of PCN is: Why isn’t a standard optician’s certificate suitable? It would be reasonable to assume, as these are the professionals, that they would be ideal to carry out tests relating to our vision. Interestingly, there are no standard requirements for near distance acuity tests, unlike far distance acuity testing. Your vision may be referred to as 20/20 (metric equivalent 6/6), which relates to you being able to see, at a distance of 20 feet (6 m), separate contours that are approximately 1.75 mm apart. 20/10 is better than 20/40. When you visit an optician, have you ever observed them taking a light reading or measuring the distance from your eye to the chart? If they did, were the measuring devices calibrated? Probably not. To correct near distance acuity you can purchase, from many outlets, reading glasses and, by trial and error, you choose the most suitable pair. An optician is doing something similar as different lenses are placed in front of your eyes as you try to read the letters.

If the chart consisted of white letters on a black background, rather than the other way round, you would probably be able to see smaller text. Also, if the smaller letters were at the top, you would probably be able to read the smaller text.

During the ageing process, our vision does decline and in middle age this becomes noticeable. Unfortunately, in our politically-correct times, this cannot be considered when determining the time between vision tests as it would seem to be ageist. So, a 20 year-old has to be treated the same way as a 60 year-old and be tested annually instead of biannually.

john.moody@bindt.org

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