Purpose:

To describe the optimization of A-constant when using an auto refractive device vs. when using standard manifest refraction. Setting: Prospective, Non-Randomized, Observer-Masked, Multicenter Study.

Methods:

Adult subjects in need of cataract surgery with implantation of a monofocal IOL were recruited to participate. Subjects who satisfied the study eligibility criteria completed cataract extraction surgery and were implanted with an ACRYSOF IQ Monofocal IOL, Model SN60WF in 1 or both eyes. IOL SRK/T A-constant estimated based on the preoperative biometry, IOL power and postoperative manifest spherical equivalent refraction and using a Topcon KR auto refractor at 3 months follow up. The examiner performing manifest refraction was masked to the refractive target and refractive error from the surgical planning and the operative visit. All subjects were follow up for up to 3 months.

Results:

A total of 162 subjects were enrolled into the study, 150 subjects were successfully implanted with the monofocal IOL and 148 completed the study. Mean difference between manifest refraction and auto refraction A-constants.

Conclusions:

): A-constants as determined by manifest and automated refraction methods differed in a clinically insignificant manner. Small differences in A-constants between sites reflects differences in surgical practice.