Do I need to perform a spherocylindrical over-refraction?
If the lens axis is stable and the rotation is consistent with the refractive cylinder axis, it is not routinely necessary to perform a cylindrical over-refraction with today’s soft toric lenses. However, if rotation is observed, it is safe to assume that any resultant cylinder is being induced by the rotation. It is therefore recommended that after a spherical over-refraction is performed, the rotation be compensated based on the amount of rotation observed. Example: To determine if the appropriate amount of astigmatic power in the contact lens was selected, it may be valuable to test 0.50D of cylinder power on axis and 90 degrees away from the axis. If the patient accepts the 0.50D on axis, then they may need additional cylinder power. If they prefer their vision with the 0.50D 90 degrees away, they may benefit from a reduction in cylinder power.
