So a long time ago I found out that lens replacement in glasses sucks; I had a pair of glasses that I was perfectly happy with and I didn’t feel like buying new frames, just wanted to update my prescription. Unfortunately, I’d purchased the frames at a different vision center, so my new vision center didn’t have the data on the frames on file. So, what they could do was measure the lenses and then attempt to grind a pair that would fit. I said sure, waited 10 days, and then went to get the new lenses. The tech realized in relatively short order than with an eighth of an inch gap between the lens and the frame, that they probably weren’t going to fit. I guess for their first measurement they were using My First Ruler, with quarter-inch graduation, and guessed the next significant digit. Realizing their measurements were obviously off, they removed and re-measured the lenses, and sent off directions to the grinder. This time they came back about an eighth of an inch too big.
I now realized that even if they averaged their measurements the third time around, they surely were going to screw up the curvature in one dimension, and the lens would either break the frames or fall out regularly. Thus, I retreated 300 miles away to my original office and had them fill the new prescription in the old frames. Magic.
Interestingly enough, my computer/reading glasses fragmented the other day, and now I can’t look through the left eye without getting a headache. These glasses just have a very minor correction, to try and abate astigmatism and a mild farsightedness (on the whole, I’m nearsighted, but text smaller than 12pt is blurry at reading/computer distance). As such, I wasn’t concerned about changing their prescription, as unlike my nearsightedness (which has actually improved in the last 4 years), my near vision really hasn’t changed.
So, I called my old vision center in Michigan where I got these glasses, having before learned that there was no way to replace the lenses without going to the original location.
After a long conversation debating the merits of getting a new prescription (“Really, I just want to replace the lens, I don’t care if my eyes have changed and I’m destroying my vision and brain by using an old prescription. Humans got by for millennia without these damn things, a 1% change in vision isn’t going to kill me…”), I finally convinced them I just needed a replacement lens, and nothing more.
“Well, you’re going to have to bring them in and have the lenses measured, since we don’t have that data on file anymore.”
Huh? Here’s the short story.
Apparently frame and lens geometry has a shelf life of 3 or less years, after which time the frames are discontinued, and any records of these specifications vaporize. I guess the eye doctors just send the prescription information, but the grinders actually are the only ones with information on frame/lens geometry, and they destroy this information to force you to buy new lenses and frames every three years. What a crock. I don’t want to dump several hundred dollars to buy a pair of computer glasses, when my normal glasses need to be replaced (which will eat my insurance contribution) already.