Comparison of optical quality and intraocular scattering after femtosecond LASIK and posterior chamber phakic intraocular lenses implantation

Abstract

Objective To compare optical quality and objective intraocular scattering after femtosecond laser in situ keratomileusis FS-LASIK) and implantable collamer lenses (ICL)implantation for high myopia.Methods This observational case-control study selected 44 consecutive patients (ages range from 18 to 40 years) with myopia between-6 D to-12 D,of which 24 cases (48 eyes) accepted FS-LASIK surgery and 20 cases (40 eyes) underwent ICL implantation.In addition to the corneal thickness (t=4.77,P＜0.05),all the preoperative data were matched between the two groups.Measurements were performed one and three-month postoperatively by a double-pass optical quality analysis system (OQASTM,Visiometrics,Spain).We assessed the objective scattering index (OSI),modulation transfer function (MTF) cutoff frequency,Strehl ratio and OQAS values (OVs) at contrasts of 100％,20％ and 9％.Paired t test for data comparison within group and independent sample t test between groups were used for statistical analysis in postoperative 3 months follow-up.Results After 1 month,except for residual mild astigmatism (t=4.95,P＜0.05) and more safety index (t=2.22,P＜0.05) in ICL group,no significant differences were found between the groups in UCVA,BSCVA and equivalent sphere refraction.After 3 months,while no significant change of equivalent sphere refraction in ICL group compared with 1 month,50％ eyes in FS-LASIK group had an average refractive regression of-0.72±0.72 D.We also found no significant differences in the MTF cutoff frequency,Strehl ratio,100％OVs,20％OVs,and 9％OVs between groups after 1 and 3 months,only OSI of ICL surgery after 1 month was greater than FS-LASIK group (t=2.14,P＜0.05).Conclusion Either FS-LASIK or ICL implantation could effectively correct high myopia range from -6 D to-12 D; However,ICL implantation was safer and more stable when compared with FS-LASIK surgery.Although early objective intraocular scattering after ICL implanted was slightly higher,the overall results of postoperative optical quality were similar. Key words: Myopia; Femtosecond laser; Keratomileusis,laser in situ; Phakic intraocular lenses; Optical quality; Intraocular scattering; Double-pass technique