I’ve noticed that when I change the prescription of a person (because I have found a change during refraction) who is happy with their vision and has no symptoms they often complain of problems with the new prescription. Do you have any advice?

I was reading a research article on intolerance to new spectacles in UK practices.

The researchers found that 83% of intolerance to new spectacles was due to poor-quality refractions.

The main refracting issues highlighted by the researchers were:

Don’t reduce the minus in a happy myope.

Overplussing or underminusing accounted for 26% of causes, while underplusing and overminusing accounted for only 11% of causes. Thus it could be better for tolerance to ‘reduce the plus’ or not reduce a happy myope and think ‘if it ain’t broke don’t fix it (much).’

 If it ain’t broke, don’t fix it

Patients who reported no problems at the initial examination accounted for more than one-third of all rechecks. Where the recheck prescription was returned to the habitual finding or within half the difference of the test-habitual prescription, just one patient reported being unhappy. If either rule, ‘if it ain’t broke, don’t fix it’ or ‘if it ain’t broke, don’t fix it (much)’ had been applied to such patients, one-third of all rechecks could have been avoided.

 Oblique cylinder

Changes in cylinder power or axis accounted for 38% of all prescription-related causes of rechecks, and patients with changes in oblique astigmatism were approximately twice as likely to report problems than those who have with- or against-the-rule astigmatism.

I know that it can be very difficult not to prescribe the ‘optimum refraction’ especially after we have gone to a lot of effort to determine it but prescribing lenses is an art as well as a science. The science is in the refraction and the art is deciding how much of the refraction to prescribe to the patient.

Take a moment to think whether a myopic patient without symptoms really does need a reduction in minus or if the patient really does need a change in oblique cyl power and/or axis.

Some patients will benefit from not being prescribed the ‘optimum refraction’.


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