Accuracy of minus power intraocular lens calculation using OKULIX ray tracing software.

PURPOSE

The purpose of this retrospective study was to assess the accuracy of minus power intraocular lens calculation using partial coherence interferometry and OKULIX ray tracing software.

METHODS

We included 25 consecutive, myopic eyes with axial length ≥ 30 mm (25 patients, 13 males and 12 females, and 57.6 ± 10.3 years old), which underwent phacoemulsification and implantation of a minus power intraocular lens in the capsular bag. Axial length measurement and corneal topography were performed using the OA-1000 optical biometer and Topographic Modeling System TMS-5, respectively. The IOL power was calculated using SRK/T formula and OKULIX ray tracing software. The implanted IOL power was chosen based on OKULIX ray tracing software calculation aiming for - 2 diopters (D) of myopia.

RESULTS

SRK/T calculated IOL power (- 6.3 ± 2.8 D) showed statistically significant difference compared to OKULIX calculated IOL power (- 4.7 ± 2.6 D), r 0.994 p < 0.001. The expected refraction with implanted IOL was - 1.7 ± 0.9 D based on OKULIX ray tracing software calculation. A statistically significant difference was reported between implanted IOL and OKULIX calculated IOL power (2.7 ± 1.4 D), r 0.981 p < 0.001. A statistically significant difference was reported between the expected refraction with implanted IOL and the achieved spherical refraction at 1 month postoperatively (1.4 ± 0.7 D), r 0.77 p < 0.001. The achieved spherical refraction at 1 month postoperatively was 0.2 ± 0.2 D.

CONCLUSIONS

Although OKULIX ray tracing software yielded more accurate minus power intraocular lens calculation in extreme myopia, compared to SRK/T formula, yet it still shows tendency toward hyperopia.