Karim Mahmoud Nabil1. 1. Department of Ophthalmology, Faculty of Medicine, University of Alexandria, 19 Amin Fekry Street, Raml station, Alexandria, 21523, Egypt. Karim_nabil_ophth@yahoo.com.
Abstract
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), rs 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), rs 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), rs 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.
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), rs 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), rs 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), rs 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.
Entities:
Keywords:
Extreme myopia; Minus power intraocular lens calculation; OKULIX ray tracing software; Partial coherence interferometry