Wow, I had no idea answering this question would be tougher than solving the mystery of the oracle - Beth you're the only person who was able to answer it and I posted to a few forums. I think I'll copy and paste your reply in case anyone looking at those forums wants an answer. Thanks a lot.
I saw two optometrists because of an insurance change, FYI. Because I didn't have an answer I went ahead and ordered two pairs of glasses, each based on a different prescription. I've worn each pair for a day so far and honestly I don't notice a difference; they're both great. I haven't yet tried an eye chart which I'll probably do just because I'm curious. By the way, I got both pairs from eyebuydirect for $30 w/ the glassy eyes discount and I'm very happy with them. On Aug 17, 10:55 pm, Beth <[email protected]> wrote: > I'm not an optometrist or an optician, but I think I can help with > this based on an explanation that an experienced optician gave me > yesterday about my own prescription (and a course in general optics > that I took). He indicated that the strength of the glasses (overall) > comes from the addition of the spherical and cylindrical (which is > applied at an angle, the axis) values. In my case, I had asked why I > have -9.00 in one eye and -7.75 in the other (for the spherical); he > pointed out that the -1.00 and -1.75 for cylindrical on my > prescription balanced it out, as it turns out more like a total of > -10.00 on one side and -9.50 in the other. > > To apply this to your question, you had -2.25 and -2.00 total. Now > you have something like -2.50 and -3.00. So, basically, they moved > one of the correcting forces off from the side, onto the front, at > least as I understand it, so your overall prescription went up. I > likened it to vectors to see if I was understanding it the same way as > the optician at the store did, but he didn't really confirm the > application of this analogy one way or the other. Check out something > on vector addition for more detail on this explanation, which may be > correct. > > On Aug 12, 7:51 pm, phillo <[email protected]> wrote: > > > > > I visited 2 optometrists 1 year apart and now need to order new > > glasses but when I compared the newer prescription to the older 1 this > > particular difference jumped out but doesn't make sense: > > > old script - OD-CYL:-2.00 > > > new script- OD-CYL:-1.75 > > > I'm assuming that closer to 0 = less correction so -2.00 should be the > > newer prescription/more correction but I'm having a hard time > > validating or negating this assumption online and I'm in contact with > > neither of the optometrists that examined me. If anyone could clarify > > I'd really appreciate it. > > > FYI COMPLETE PRESCRIPTIONS > > > Old script: > > ____________ > > OD-SPH:-0.25 > > OD-CYL:-2.00 > > OD-AXIS: 95 > > --------------------- > > OS-SPH:-.50 > > OS-CYL:-1.50 > > OS-AXIS: 80 > > > New script: > > ____________ > > OD-SPH:-0.75 > > OD-CYL:-1.75 > > OD-AXIS: 95 > > --------------------- > > OS-SPH:-1.25 > > OS-CYL:-1.75 > > OS-AXIS: 80 -- Check us out at the oft-updated http://glassyeyes.blogspot.com! You received this message because you are subscribed to the Google Groups "GlassyEyes" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/glassyeyes?hl=en
