Clinic observation of intraocular lens power calculation after corneal refractive surgery

Abstract

AIM:To explore the method to calculate intraocular lens(IOL)power after corneal refractive surgery.METHODS:A retrospective study was conducted. Fourteen patients(23 eyes)with age-related cataract after corneal refractive surgery were treated in our hospital from March 2013 to June 2015. Patients were divided into LASIK group(laser in situ keratomileusis, 9 cases with 15 eyes)and RK group(radial keratotomy, 5 cases with 8 eyes). Corneal curvature values of the lowest point in central 2.5mm were measured by corneal topography, which were used in SRK-T formula. Phacoemulsification with IOL implantation was performed with the target refraction was between -1.0～-1.5D. The patients were followed up for uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA)and refractive statuses at 3mo after the operations. The predictive error of the calculation formula were calculated and compared to Shammas formula and Barrett True K formula from www.iolcalc.org respectively. Statistical analysis of the data was performed using independent-samples t test.RESULTS:The UCVA(LogMAR)of LASIK group and RK group were 0.15±0.11,0.21±0.16 respectively, refractive status were -0.43±1.04,-1.52±1.01D and the predictive errors of the SRK-T were -0.71±0.80,0.43±0.99 at 3mo after operations. There was significant differences(PCONCLUSION:Our results imply that using our observed method, the postoperatively predictive errors are mild myopia, which can be applied for determination of IOL power for cataract patients who received corneal refractive surgery. And it can improve accuracy of the intraocular lens power calculation for cataract patients with corneal myopic refractive surgery, especially for patients with LASIK.

Keywords

• cataract
• intraocular lens calculation
• refractive surgery
• keratometry