What happens if your eyeglass power axis is off by 5 degrees
Answers
Hi my dear friend,
The thing about a prescription that is affected by the axis is the cylinder-ie the correction for astigmatism.
Generally speaking, if the glasses axis is different from your real axis by a few degrees, you wouldn't notice a difference. Just like spherical power, there is a margin of error with the axis and I would say about +/- 5 degrees is fine.
If it is off by 10 degrees, then you would have 1/3 of the original astigmatism amplitude remaining, and if it is off by 30 degrees, then the amplitude would be the same as what you started off with, but at a different axis. If the glasses axis was at 90 degrees to your real axis, then your astigmatism amplitude would be doubled (while wearing the glasses)
The further off it is, the more residual astigmatism you will have and the more remaining blurring you may have. At certain angles, residual astigmatism may cause visual distortion and dizziness. However, this does not damage your eyes. Just have the prescription rechecked at the optometrists', and change the glasses if necessary.
~Thank you