How long should I give patients when it comes to choosing which view is best when choosing between different spherical and cylindrical lenses and between different axes when I’m correcting astigmatism?

I’ve mentioned before that many patients dread having an eye examination because they are fearful of giving the wrong answer to a question asked by the eye specialist. They are worried about getting the wrong glasses, not seeing well enough, and thereby being forced to decide whether to make a complaint or suffer the financial cost and go elsewhere.

I have advised to go slowly when needed and to make the choices the patient faces as easy as possible. We often ask ‘Which is better, one or two?’  This is a crucial part of the eye examination and the practitioner must maintain control. If the patient gets control, they may ask the practitioner to repeat the choices many times.

A good way to avoid this is to ask the patient to choose the lens which, on the very first impression, gives the best view of whatever target (letters, spots, or circles) you have asked them to look at while comparing the lenses.

I’ve seen students and novices flip lenses from one choice to another too quickly during an examination. This is not surprising as they are usually under time pressure and don’t have the experience, yet, to complete an examination in the time allowed them, so they try to do everything quickly.

Rushing the lens choices means the patient is given very little time in between to focus on what they’re seeing and decide where it ranks. This necessitates many flips and leaves some patients feeling certain they made a mistake. I think staying on each lens choice for about three seconds leads to a definite selection after only one flip the majority of the time.

Do remember though as you get closer to the optimum lens or axis the difference in view produced by the lenses becomes less and less making it difficult for the patient to choose. This is a good thing from the practitioner’s point of view as it means the optimum lens has almost been found. It is worth telling the patient that as you get close to the best lens for them it will be harder for them to see any difference between the lenses you show them.

Given this, it is important to know that patients do not always respond accurately during testing with the Jackson cross-cylinder and during duochrome testing. This is why starting with an objective assessment of the patient’s refractive error will help you stay on target with your refraction.