This article is more than 5 years old. Information may no longer be current.
Accounting for refractive error in first eye may minimize error in second eye
Ophthalmology. 2010;117(1):49-54.
Click Here to Manage Email Alerts
Determining the difference between predicted and observed postoperative refractive error in the first eye reduced error in the fellow eye in patients undergoing bilateral cataract surgery, according to a study.
"One could speculate that the error of predicted refraction observed in the first eye could be related to that of the second eye," the study authors said. "If this relationship were known and consistent enough, surgeons could incorporate it into the choice of IOL power for the second eye in an attempt to improve refractive results of the second eye."
The retrospective study included 206 patients who underwent bilateral, sequential phacoemulsification and IOL implantation. Mean patient age at the time of the first surgery was 69.9 years. The mean interval between first and second surgeries was 36.7 days.
Investigators compared observed second eye 1-month postoperative spherical equivalent refractive error to calculations of the hypothetic 1-month postoperative spherical equivalent refractive error in cases in which the first eye error was partly or completely factored into the IOL power for the second eye.
Error of predicted refraction was "the difference between the actual or hypothetic spherical equivalent refractive errors and those predicted by preoperative calculations," the authors said.
Study data showed that that the optimal amount of adjustment of second eye IOL power was 50%.
Postoperative spherical equivalent refraction was within 0.5 D of predicted refraction in 66.5% of unadjusted second eyes, 67% of hypothetic fully adjusted second eyes and 74.3% of hypothetic partially adjusted second eyes.
Postoperative spherical equivalent refraction was within 1 D of predicted refraction in 90.3% of unadjusted second eyes, 90.8% of hypothetic fully adjusted second eyes and 93.7% of hypothetic partially adjusted second eyes, the authors reported.
With advanced techniques and precise preoperative measurements, predictable refractive outcomes after cataract surgery are now possible. Methods of enhancing the precision of determining appropriate IOL power are continuously sought. In this article, Covert and colleagues have found that using refractive outcomes from the first eye undergoing cataract surgery can improve those of the second eye. In a retrospective study, the authors determined that adjusting the second eye IOL power by 50% of the observed error of the predicted refraction of the first eye enhanced predictability. An adjustment of 50% was even more precise than an adjustment of 100%. This novel approach is of importance to surgeons who seek to achieve precise refractive outcomes. The next step will be validating this process in a prospective study and broadening the applicability to other surgeons and IOLs.
– Elizabeth A. Davis, MD, FACS
OSN
Cataract Surgery Board Member