The Comparative Analysis Of IOL Master And A Ultrasound Combined With Corneal Topography Measurement For IOL Power

Objective To investigate the difference of IOL Master and A-ultrasound combined with corneal topography measurement in intraocular lens (IOL) power calculation.Methods Selected60cataract patients of84eyes received phacoemulsification and intraocular lens implantation surgery in Xiangya Hospital from March2010to September2011. There are42age-related cataract patients of57eyes andl8complicated cataract patients of27eyes with high myopia. The patients were then divided into IOL Master group and A ultrasound combined with corneal topography measurement group. Before surgery, in IOL Master group, axial length(AL) and corneal curvature were measured with IOL Master and A ultrasound combined with corneal topography measurement respectively, IOL power were calculated according to the Haigis, SRK-T formula and so on, while the axial length(AL) and corneal curvature were measured with A ultrasound combined with corneal topography measurement again, and IOL power were calculated by SRK-II formula. In A ultrasound combined with corneal topography measurement group, axial length(AL) and corneal curvature were measured with A ultrasound combined with corneal topography measurement respectively, IOL power were calculated according to the SRK-II formula. After3months postoperatively, all the patients were conducted refractive outcome and calculating mean absolute refractive error (MAE). The axial length and corneal curvature of both groups patients were measured with IOL Master. Then perform statistical analyses.Results (1) In IOL Master group, there was no significant difference in axial length between IOL Master measurement (23.16±0.43mm) and A-ultrasound measurement (23.08±0.41mm)(P>0.05); There was significant difference in corneal curvature between IOL Master measurement (42.12±0.31D) and corneal topography measurement (43.09±0.27D)(p<0.05); there was significant difference in IOL power between IOL Master measurement (17.06±0.48D) and A-ultrasound combined with corneal topography measurement (16.37±0.56D)(p<0.05).(2) After3months postoperatively, axial length, corneal curvature and IOL power of IOL Master group (axial length:23.16±0.51mm, corneal curvature:42.12±0.43D) were measured by IOL Master (axial length:23.04±0.56mm, corneal curvature:43.15±0.34D) again. There was no significant difference with axial length between with Preoperative (P>0.05). There were significant differences with corneal curvature between with Preoperative (P<0.05). After3months postoperatively, axial length, corneal curvature and IOL power of A ultrasound combined with corneal topography measurement group (axial length:22.96±0.37mm, corneal curvature:43.18±0.41D) were measured by IOL Master (axial length:22.76±0.56mm, corneal curvature:41.78±0.34D). There was no significant difference with axial length measured by A-ultrasound combined with corneal topography measurement group before surgery (P>0.05). There were significant differences with corneal curvature measured by A-ultrasound combined with corneal topography measurement group before surgery(P<0.05).(3) There was significant difference in MAE between IOL Master group (0.07±1.05D) and A-ultrasound combined with corneal topography measurement group (0.16±0.81D)(p<0.05); There was significant difference in percentage of patients between IOL Master group and A-ultrasound combined with corneal topography measurement group when MAE>2.00D (p<0.05). Conclusion Compared to A-ultrasound combined with corneal topography measurement, IOL Master is more accurate in axial length measurement of the high myopia, corneal curvature and IOL power calculation.