Question
dear ma'am,
I had a recent eye check up. my power details are as follows-
right eye: sph : -9.5 cyl: -0.5 axis: 75 degrees
left eye: sph: -8.5 cyl: nil axis: 25 degrees
my old prescription-
right eye: sph : -10 with same cylindrical.
left eye : sph: -9.5
The problem is when I got my new pair of glasses, the glass seems to be very thick at its edges and causes discomfort when I try to look at the corners. whereas by old pair of glasses don't appear that way, though made with a higher power compared to the new one. I use a high index glass of 1.8. totally I don't feel comfortable wearing the new specs. I would be glad if you can help me with this problem.
thanking you,
yours sincerely
Sudha
Answer
Possible reasons for your problem are listed below:
1) are your sure both your old glasses and the new ones are made of high index material? Are you sure they are GLASS? We don't really use glass lenses in the US anymore.
2) Even if they are both high index material, there could be differences between one brand from one lens company and another.
3) there could be different base curves used. Base curve is not part of the prescription but it refers to the curve of the front side of the lens. the same prescription could be made with any number of different base curves by altering the back curve. Only a very few people are sensitive to base curve differences so usually no attention is paid to matching base curves to a prior pair. If you find that this is the problem, have your optician tell you what base curve your old glasses were and then always ask for that curve when ordering glasses. You can go back to the optical shop and have them measure the base curve of both sets of glasses. if there is a difference, ask to have the new glasses remade with the curve of the old glasses.
4) there could also be a difference in the way the optical centers were measured. Ask the optical shop to remeasure the OC's on both pairs to see if they fall in a different spot on your face.
5) the new glasses may be adjusted in such a way that the lenses fall at a different angle on your face. Ask the optical shop to try and match the adjustment of the new pair to the way the old pair was adjusted.
6) the new frame may be larger than the old one. The larger the frame, the farther from the center the lens goes out and the more likely there are aberrations in the lenses at the edges. Picking a smaller frame (with fewer millimeters from your pupil to the edges in all dimensions) may resolve this.
7) If none of the above suggestions work, you should go back to the doctor who wrote the prescription to see if by chance the new one is not correct for you.
