At what power do you make adjustments for vertex distance?

The correct power at which adjustments for vertex distance are typically made is around plus or minus 4.00 diopters. This threshold is important because vertex distance adjustments are necessary when the distance between the lens and the eye changes, which can significantly affect the effective power of the lens.

For prescriptions that fall outside of this range, adjustments are generally less significant because the effects are more pronounced at higher powers. At plus or minus 4.00 diopters, the change in power due to vertex distance becomes more critical, as the eye's optical system is more sensitive to variations in distance at these levels. By making adjustments at this specific power, practitioners can ensure that the contact lenses provide optimal visual acuity and comfort to the patient while taking into consideration the impact of the vertex distance on lens fitting and performance.