Optician India

Welcome to question of the day #129

Many people in my community have untreatable eye diseases. I can’t help them with traditional spectacles. What can I do?

You can set up a low vision service in your practice. This needs some financial investment but not a lot and this will be returned from the fees you can charge for the service and for supplying magnifiers.

Here is my opinion on what equipment is needed to set up a low vision service.

A logMAR type of visual acuity chart for distance. See figure. This gives a more accurate visual acuity measurement than Snellen. Each letter has a value of 0.02 and all the letters correctly identified can be added to give an overall score. This is a much better way of handling letters identified from a spread of lines. Some practitioners are using the number of letters correctly identified as the measure of visual acuity rather than the logMAR value.

A logMAR type of visual acuity chart for near. See figure. This has the same advantages as the distance chart. It also has a guide attached to make sure the correct working distance is used in order to validate the visual acuity levels printed on the card.

A Pelli-Robson contrast threshold chart. See figure. This is very important as people with low scores on this test will not benefit from stronger glasses or from magnifiers. It would be a waste of time trying to find a refractive/optical magnifier solution under these circumstances. Time should be spent on other forms of low vision rehabilitation such as reading substitution or electronic magnification with contrast enhancement.

A selection of simple hand-held magnifiers for trial during the low vision assessment and for supply. See figure.These are best used with distance glasses if the person needs them.

A selection of simple stand magnifiers for trial during the low vision assessment and for supply. See figure.These are best used with near glasses if the person needs them. Further information on this in a later Question of the Day.