Howdy,
Been years since I last wore glasses but I'm after some now as I'll soon be starting a course that I expect will have classroom learning and whiteboards to read in lectures and whatnot.
In the past I've had issues with being given a bad prescription for glasses lenses, and I think I may have run into the same problem again.
I went to two opticians and got two prescriptions which - given my basic knowledge and some googling - I think are
not equivalent. Both prescriptions seemed to work okay during the tests but I don't want to go through the weeks of adjusting to new glasses only to find that the lenses are wrong or there was a better choice.
Before I go pay for yet another eye test, is there anyone around who could shed some light on the situation?
Prescription One:
- SPH CYL AXIS
R - 1.00 - 1.25 180
L - 1.75 - 1.50 5
Prescription Two:
- SPH CYL AXIS
R - 0.75 - 1.00 5
L - 1.75 - 1.25 5
It looks to me like the astigmatism on the right eye is being corrected along an entirely different axis. If the two proposed axes were 90 degrees apart I can see how altering the power can give an equivalent geometry, but this isn't a 90 degree separation so I can't see a symmetry - seems like it's just going to be a completely different lens. I dunno man I almost failed my optics module at university.
My main question is 'Are these prescriptions equivalent?', followed by 'Is this sort of thing at all common?'.
I appreciate that people aren't doctors and even if they are they aren't
my doctor, so don't worry, anything suggested will be run by my actual doctor before anything is done, I'm just looking for information here.
Cheers!
Posts
These prescriptions are not very far away from each other at all since prescriptions are generally done in .25 intervalls.
L eye is basicly the same, with a one-step difference on one axis.
R eye also almost basicly the same, since AXIS has a value from 0-180 (and some schools write 180 instead of 0, but it's the same since a 180 degree rotated cylindrical lens is the same as a 0 degree rotated one). That means that the rotation is basicly 5 degrees off, which isn't that strange given that it's very weakly astigmatic.
-Antje Jackelén, Archbishop of the Church of Sweden