Refractive stabilization and corneal swelling after cataract surgery

To determine the earliest time after cataract surgery when corneal swelling and automated refraction are stabilized sufficiently to allow reliable refractive prescription.

This was a prospective, nonrandomized, case series study of 124 consecutive eyes undergoing uneventful cataract surgery. Automated refraction and central corneal thickness (CCT) measurements were made at baseline before cataract surgery and on follow-up visits 1 day and weekly for 4 weeks afterward. Corneal swelling was determined as the percentage change in CCT after surgery. To determine the validity of automated refraction, it was compared with subjective refraction at the final visit.

Corneal swelling decreased between the first postsurgical day and the first week and again between postsurgical weeks 1 and 2 (p < 0.01 each). Although thinning continued through the fourth postsurgical week, the changes were not significant. Both spherical and cylindrical refraction were stable 1 week after surgery, with the greatest change between the first postsurgical day and 1 week (p < 0.01). In replicate measurements of automated spherical refraction taken on the last visit, the intraclass correlation coefficient was 0.93. For automated cylindrical refraction, it was 0.81.

Automated refraction is highly repeatable and can be used to monitor postsurgical refractive changes. Whereas corneal swelling becomes stable 2 weeks after cataract surgery, automated refraction becomes stable after 1 week and can be used to accurately prescribe corrective lenses at that time.