Surgical-induced astigmatism via a 5.5mm superior scleral tunnel incision for implantation of an Artisan phakic intraocular lens / 中华实验眼科杂志

ABSTRACT

Background Surgical induced astigmatism induced by a 5.5mm of superior scleral tunnel incision is a key cause of influencing vision outcome in the high myopic eyes after implantation of Artisan phakic intraocular lens(IOL).Objective This study was to evaluate the surgical induced astigmatism through a 5.5mm superior scleral tunnel incision during the implantation of Artisan phakic IOL.Methods This was a case observational study.The clinical data of 202 eyes of 111 patients with Artisan IOL implantation for high myopia from October 2004 through October 2008 was collected.The patients were followed-up for 12 months.The uncorrected visual acuity(UCVA),best spectacle-corrected visual acuity(BCVA),spherical equivalent(SE),cylinder equivalent(CE) and cylinder axis were examined before surgery and postoperative 1,3,6,12 months.The patients were divided into with rule group and against rule group according to the cylinder axis.Surgery-induced astigmatism value was calculated using Holladay vector analysis formula.This clinical trial was approved by the Ethics Committee of Guangdong General Hospital.Written informed consent was obtained from each patient prior to the surgery.Results The UCVA of 195 eyes(94.1%) was 0.5 or better in postoperative 12 months,and that of 172 eyes(85.1%) showed the improvement of BCVA during the follow-up duration.The mean CE values were reduced in 1,3,6,12 months after surgery in comparison with before surgery(t=-4.30,P=0.00;t=-2.27,P=0.01;t=-2.04,P=0.04;t=-2.79,P=0.01).Vector analysis of total surgically induced astigmatism revealed that the mean incision-induced astigmatism value was +1.94D,+2.26D,+2.29D,+2.25D at 171°,170°,181°,175° in 1,3,6,12 months after surgery.The surgery-induced astigmatism was(+1.97±1.84)D,(+2.25±1.75)D,(+2.27±1.76)D,(+2.24±1.75)D in with rule group at postoperative 1,3,6,12 months respectively;while those in against rule group was(+1.75±1.88)D,(+2.35±1.74)D,(+2.38±1.76)D,(+2.34±1.74)D respectively.No significant differences were found between the two groups(t=0.54,-0.29,-0.27,-0.29;P=0.59,0.78,0.79,0.78).Conclusion Implantation of Artisan IOL is an effective approach for correction of high myopia.A 5.5mm superior scleral tunnel incision in operation induces a +2.25D astigmatism at 175° meridian.