Can someone help me figure out what my eye doctor was talking about?

I had an eye exam last week and am getting new glasses (actually the same prescription as my old ones, but the coating is coming off the ones I have).

Something he pointed out was that my prescription should be -4.95 in both eyes, objectively, but when I am given the choice between that prescription and a -5.95, I choose the higher prescription. He suggested I might have something muscle-related in my eyes and asked if I had ever been tested. I said no and he said the treatments likely wouldn’t do much if anything for me now at age 42. We dropped the subject.

I just started thinking about it and wanted to see what it was he meant. Can anyone help?

Eyes that drift in or out can sometimes be fixed by using strong plus lenses to pull the eyes back to the center if started young enough.

I think you might be confused about the prescription, though. If I had ordered lens blanks in -5.95 or -4.95 I would have gotten a call from the wholesaler asking what I really wanted. Lenses normally are made in quarter diopter increments (.25,.50, 75, .00). Sometimes doctors will order them in eighth diopter increments, but no less. -5.95 is well within ANSI tolerance for a -6.00 prescription, and not far out of tolerance for a -5.75 prescription.

Vision correction is not an absolute. A savvy optometrist will try to give you the best correction, not necessarily the numerically-correct one. I’ve had prescriptions that were a full diopter off of “perfect” because they gave me more natural control of my vision and focus.

Hard to say exactly what yours meant, but it may mean that your comfortable focusing range works better with the higher correction even if technically you are doing something counterproductive - e.g., deliberately under- or over-focusing. Rather than train you out of the bad habit at this late stage, he just gave you the correction that works for you.

Yeah, I don’t have the prescription in front of me, so I’m not surprised that I got it wrong.

For years my optometrist would put a little “english” into my prescription to correct for a weak muscle in one of my eyes.

After I retired and moved, my new opthomologist no longer does so. I can detect the difference; when my eyes get tired now, one of them goes walleyed on me. Of course that is rare as I am retired.

A script that is too weak leaves you to get eye strain.

If its too strong, then your lens adjustment muscles may weaken and it may be harder for you to adjust focus, so you must keep the stronger script.

As you are 42, he decided that it may be presbyopia, permanent weakness in focusing - and its too late now to put you back to a weaker lens .

If you wanted to do a fairly cheap experiment, you could try a pair of glasses at the weaker Rx from a place like Zenni Optical, and see whether it helps you focus on your own better or just leads to the fatigue your eye doctor likely thinks it would. Your doctor would have to agree to writing you an Rx for both, though.

Zenni does not require a copy of the prescription so you can just manually enter what you want. It would not be necessary for your doctor to give you two prescriptions.


It depends. When I ordered, I have enough discrepancy between each eye, apparently it’s weird enough, and my left astigmatism is bad enough, they emailed me a request to send my Rx after I ordered. I had to send them the PDF from my doctor before they would make the glasses. YMMV.

He definitely didn’t say I couldn’t choose the weaker prescription. He gave me the choice between the two and showed me the difference and I chose the stronger one. And considering my current glasses are at the stronger prescription, he said he assumed the previous optometrist did the same thing without telling me exactly what he was doing.

He just said my preference for the stronger one was potentially indicative of something muscular. I wondered what that something was.