Careful refraction must be performed on both eyes. This assessment is useful for choosing the IOL power necessary to obtain the desired postoperative refraction, as well as for determining whether a myopic shift has occurred. If the fellow eye has a clear lens and a high refractive error that requires correction, achieving emmetropia in the surgical eye might cause problems with postoperative anisometropia. It is important to inform the patient specifically about this possibility and discuss options including refractive surgery or use of a contact lens for the noncataractous eye. Postoperative anisometropia can also be an indication to proceed with surgery on the second eye, even if there is minimal cataract present. Aiming for a similar refractive result in the fellow eye is an option, but this will ensure long-term dependence on refractive correction. A planned monovision outcome may optimize spectacle independence, but the patient either must have experience with monovision or must be tested to find out whether adapting to unequal refractive errors will be tolerated.
Rigid contact lens overrefraction is a useful technique to assess the degree to which irregular astigmatism or other corneal irregularity is contributing to a patient’s visual disability.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.