Can I trust my eyes? Or my ophthalmologist?
January 27, 2015 10:44 PM   Subscribe

My new prescription is dramatically different from my old one from just a couple of years ago... does that make sense?

Desperately in need of new glasses (the Costco frames I got a few years ago turn out to have a 'self destruct after three years' feature in both temples), I saw an ophthalmologist and set about finding a pair of glasses for my new prescription. Along the way, I came upon my receipt for my current pair (from summer 2011) -- and was really surprised at how different the prescriptions are.

The only commonality is the right eye's sphere value (-6.75). The left eye's 'cylinder' value has gone from nothing to +0.75, and its axis has gone from nothing to 180. The left eye's cylinder has gone from -1.0 to +1.0, and its axis has gone from 177 to 085... and its sphere value has gone from -9.5 up to -11.

My left eye is definitely significantly worse than my right when uncorrected... but through my current pair of glasses (with the -9.5 correction on the left) the two just don't seem that much different -- what I can read with just my right eye I can typically also read with just my left eye as well. In fact, through those lenses my left eye sometimes feels better than the right.

Could my left eye really have gotten that much worse in just three years?

The cylinder and axis values seem totally unrelated old to new -- that also concerns me. (I'm in my mid-forties if that makes any difference.)

I remember it was quite hard to tell which of the A/B comparisons was better / worse for much of the eye test. Could that -- or incompetence on the doc's part -- have affected my test such that this prescription is not accurate? What to do?

And while I'm asking... what's the best online glasses site for high prescriptions? The ones I've looked at so far seem to sock me with different surcharges for customized lenses, extra-extra-thin lenses, etc. At this rate I'm better off just going to Costco again.
posted by sesquipedalia to Health & Fitness (5 answers total)
Firstly, if you have no cylinder value, then there is no axis on which to apply, so your right eye originally wouldn't have had a value listed - thus the right eye changes are simply a little bit of astigmatism.

As for your left eye, it's actually almost the same prescription, just written in a slightly different format:

(A totally equivalent left eye prescription to your old one written in the same format would be -10.5 sphere, +1 cyl, 87 degree axis - so a difference of 0.5 sphere worse.)
posted by Ashlyth at 11:11 PM on January 27, 2015 [4 favorites]

Personally, I would regard a progression to very subtle differences between the one/two options to be a good thing, because it means they're dialing down closer and closer to what's best for your eye. It's something I generally notice with opthalmologists (and, to be fair, the teaching hospital-affiliated optometrist they recently referred me to), whereas I've had other providers swing between what seem like wildly disparate options and I have occasionally cynically wondered if they were trying to keep my prescription within the specs for some proprietary lens system their staff would be pitching after the exam. Something about getting new prescriptions often makes me grumpy though, so I do understand feeling like something is amiss and there's nothing you can do. For me, that goes away with having the new glasses and realizing that it's actually totally fine.

I don't know what Costco charges, but I've gotten entirely acceptable glasses from Zennioptical for about $120 each.
posted by teremala at 6:03 AM on January 28, 2015

I don't know boo about prescriptions, but to answer your last question, I am legally blind without correction and Costco has the best prices on glasses I've found.
posted by notjustthefish at 7:39 AM on January 28, 2015

I've seen a few different eye doctors over the past few years - a new one each annual. Not for any reason other than that I tend to wait until the last minute & then I'm desperate for a new prescription and go to wherever takes me. So due to this, my prescription has changed every year. I guess the script is just the doctor's opinion. My prescription has gone up and down. But I have no vision complaints so I just kind of go with it. If you've been going to the same doctor every year and its changed, I would just ask your doctor about it.

And yes, I have also heard that Costco is the best for glasses as far as price goes. I also have a heavy prescription and always have to pay that extra fee so they can make the lenses smaller. So I don't think its something you will not have to pay somewhere else - think its just always going to be necessary.
posted by kmr at 10:52 AM on January 28, 2015

My partner, who is an optometrist, says this:

First of all, -0.75 cylinder in right eye is not worrying.

Left eye has actually only gone up -0.5 sphere, as the 2 prescriptions are written in + and - cyl (transposed differently). An axis of 177 at +1 is practically the same as -1 at 085, just written in a different way. Then you minus 1 from the left -9.5, to make -10.5. So your -11 has only changed by 0.5 which is nothing to worry about.

Right eye is completely normal, slight change to astigmatism.

So don't worry! Prescriptions were just written in a different form.
[I've not understood a word of this, sorry if it doesn't make sense]
posted by derbs at 11:07 AM on January 28, 2015 [3 favorites]

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