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Welcome to question of the day #393

Eyetool question of the day #393

I work in a community eye practice. Sometimes my patients complain that the working distance with their new reading prescription is too short. They want to be able to read small print and be able to hold things further away than their new reading prescription lets them. What should I do to reduce these complaints?

 Unfortunately, this happens to me as well. I was reminded of the importance of discussing working distance with patients just last week when a patient was worried that he had the wrong reading prescription because he had to hold things closer than with his previous reading prescription. I hadn’t taken the time at his examination to explain the relationship between an increase in lens power and a reduction in working distance. He was happy with how he could see with his new reading prescription and could tell his vision was better than with his previous prescription. He didn’t even mind the slightly reduced working distance but was worried that the reduction in the working distance meant that something was wrong with his eyes or with his new glasses.

 I explained that I had had to increase his reading prescription (by +0.50 DS) as he required a stronger reading lens to help make near print as clear as possible. As the lens was stronger the distance and which it worked best was shorter. I demonstrated this by moving the print beyond the focal length of the lens where the patient could see it was blurred and then moving it closer to him until it was clear. I then measured this distance (30 cm) and advised him that this was the optimum range of his new lenses. Anything held further away than this would be blurred and anything much closer than this would also be blurred. Thirty centimetres give and take around 3 cm on either side of this was the optimum range for optimum clarity.

 Of course, I should have mentioned this when I first prescribed the increase in reading add; I usually do. I usually say ‘In order for you to see better for reading I’ve made your reading prescription stronger. This means that you will have to hold things a little closer than you do with your current reading prescription. Stronger lenses work best when things are held a little closer. Not at the end of your nose of course but a couple of inches (centimetres) closer than you do now.’

I also discuss the importance of a good reading light at this point. ‘In order to read well you need three things: reasonable eyesight, which you have, the best possible glasses, which you will have shortly, and good light. If one of these is missing then reading will be difficult.’

 When I was training I was told about a practitioner who gave each patient with a new add a piece of string that was the length of their new optimum reading distance and kept the same length of string in their clinical records so if they complained about a shorter reading distance he would reach for their piece of string. Not sure if it was true but it made an impression on me. My own clinical experience tells me how important it is to discuss working distance with patients even without string.

 A quick discussion about stronger lenses meaning a reduced working distance and mention of the importance of good light for reading will lead to better-informed patients and fewer complaints.