OD. vs. MD for eyeglasses?
September 4, 2011 2:23 AM   Subscribe

Is the LensCrafters O.D. prescription screwed up or do I just not understand something?

In Dec 2010 I went to LC for an eye exam and was written this prescription:

OD sph+1.75 cyl-1.00 axis 165 add 2.00
OS sph+1.50 cyl-0.50 axis 060 add 2.00

They made these glasses but I could never see properly out of them, ended up returning them and got my previous pair which were OK but not great.

So later this year, an opthalmologist wrote me:

OD sph+0.50 cyl+1.00 axis 080 add 2.00
OS sph+1.00 cyl+0.75 axis 154 add 2.00

I am wearing these now, and they ROCK.

Are the two prescriptions as radically different as they look to me?

You are not my doctor, my opthalmologist or my optometrist and your response to this does not constitute medical advice, nor will it be taken as such.
posted by Kahomono to Health & Fitness (6 answers total)
I am not an optometrist but have done reading about this stuff. They are actually pretty similar prescriptions.

Basically, the first one corresponds to
OD sph +0.75 cyl +1.00 axis 75

The reason is that adding one diopter of cylindrical correction at a particular axis is the same thing as making the base (spherical) prescription one diopter stronger and subtracting off one diopter of cylindrical correction at 90 degrees from that axis.

Take a look at wikipedia for more info on this.
posted by bsdfish at 4:01 AM on September 4, 2011

Whoops, sign error. What I meant to say is that the first prescription corresponds to

OD sph +0.75 cyl -1.00 axis 75

Which is quite similar to your second one. So perhaps what happened is your LensCrafters glasses were poorly made.
posted by bsdfish at 4:03 AM on September 4, 2011

Ugh, actually the first post was correct and the second fix was wrong. Sigh, I'll go to sleep now. Mods, please feel free to delete the correction and the correction to the correction.
posted by bsdfish at 4:04 AM on September 4, 2011

Yes, they're really close to the same, just written with a different convention. A variation of plus or minus 0.25 in strength and a couple degrees on the axis is normal, your eyes will change that much even over the course of a day (it is the smallest difference that they will even attempt to measure).

They could have measured your pupillary distance incorrectly for the first set of glasses or they could have just made the lenses incorrectly (did you ask them to remeasure/remake them?).
posted by anaelith at 4:24 AM on September 4, 2011

Back when I first lost my vision insurance, I went to LC for an exam and new lenses. I could never see right in the lenses they made for me, based on the prescription their in-house examiner wrote.

After complaining forcefully, they re-examined me (on the house) and discovered that, for unknown reasons, their first examiner had removed all astigmatism correction from my prescription, and did not tell me that she had done so.

Just saying that my personal experience says to never completely trust LC's ability to get it right.
posted by Thorzdad at 5:11 AM on September 4, 2011

I've had glasses since I was 7 and have had a variety of optometrists, ophthalmologists, and whatever else medical eye people are called over the years. I've done the LensCrafters thing maybe half the time, the pricy ophthalmologist+boutique glasses storefront thing the other half. 100% of the time the expensive option gets me good glasses that are correct for my eyes at the time, but not always a good frame (I've had fashionable crap pushed at me a lot, too) but it's always just out of my price range. At LensCrafters, maybe half the times I've gotten glasses from them, there's something wrong with them. But the price is generally a tiny fraction of the boutique guys, they always have frames that I am comfortable in, and if I complain they're pretty good about fixing stuff.

Basically, LensCrafters is a crapshoot. Sometimes you go to one and the person doing your examination knows their stuff. Last time I went, the excellent person took over an hour making sure everything was perfect and then had me double check once she wrote stuff down and dialed it back into the apparatus a last time to make triple sure. But I've been to LCs where an examination takes ten minutes and then I have two weeks of headaches until I get them redone. If you find a great LC person, you can actually get their business card and stuff and make sure you get them for future examinations - you just have to be kind of pushy about it.

But if you have the money, an ophthalmologist that you're comfortable with is a great thing to have. If your eyes are particularly wonky for some reason or another, make sure you find one. LensCrafters is no good for anything too complex or long-term.
posted by Mizu at 6:15 AM on September 4, 2011

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