Clinical Ophthalmology (May 2017)
Preoperative measurement vs intraoperative aberrometry for the selection of intraocular lens sphere power in normal eyes
Abstract
James A Davison,1 Richard Potvin2 1Wolfe Eye Clinic, Marshalltown, IA, 2Science in Vision, Akron, NY, USA Purpose: This study aimed to assess the value of intraoperative aberrometry (IA) in determining the intraocular lens (IOL) sphere power in eyes with no previous ocular surgery.Patients and methods: We conducted a retrospective review of patients who underwent uncomplicated cataract surgery where standard preoperative (Preop) measurements and IA were performed. Calculated IOL sphere powers and postoperative refractions, both actual and theoretical, were compared based on the measurement method and lens type; lens types included multifocal, toric and aspheric single-vision non-toric IOLs.Results: A total of 160 eyes of 112 patients were analyzed. The Preop lens power calculated was the same as the IA lens power 46% of the time, though this percentage was lower for multifocal IOLs. Across all lens types, there was a statistically significant bias (chi-square test, P<0.01) toward the IA method suggesting a lower powered lens. Actual postoperative refractive errors were not statistically significantly different when categorized by measurement method. Calculated errors by measurement method showed no statistically significant differences in expected outcomes. There were 63 cases where the Preop calculation and the intraoperative aberrometer calculation differed by 0.5 D. In 56% (35/63) of these cases, the IA result was a better option, and in 44% (28/63) of cases, the Preop calculation was better; this was not statistically significantly different from random expectation (50/50, P=0.53). In the three cases where calculated powers differed by 1.5 D, there appeared to be a positive effect of adjusting the Preop power toward the IA power.Conclusion: The use of IA for the determination of sphere power in eyes with no previous ocular surgery does not appear to improve overall expected clinical outcomes, but it may be helpful in cases where the difference between IA and Preop calculations is high. Keywords: ORA, refraction, prediction error, IOL power calculation
