Thank you very much for responding to my question about the difference in the two prescriptions below:
Right Eye Sphere: -4.50 Cyl: +1.50 Axis: 105 Left Eye Sphere: -5.25 Cyl: +1.25 Axis: 90
Right Eye Sphere: -3.25 Cyl: -1.50 Axis: 15 Left Eye Sphere: -4.25 Cyl: -1.50 Axis: 176
I understand the explanation about transposing the prescriptions. However, you do not mention the large difference in the Axis numbers. Please could you explain how they are different and if it should make a difference to my vision? Thank you again for your help.
Qualified optometrist Simon Kay BSc(Hons) MCOptom answers this question.
When you transpose the prescription the axis degree changes by 90 degrees, so 105 becomes 15 in the right and 90 becomes 180 in the left which is only four degrees different in this eye. When transposing a prescription you add the sphere to the cyl, change the power of the cyl and change the axis by 90 degrees. So transposing the left eye of the first prescription you get Sphere -4.00, Cyl -1.25, Axis 180. I hope this helps.