Analysis Of The Aspherical Characteristics Of Intraocular Lens On Vertical Coma Aberration And Visual Quality

Objective:To analyze the effect of asphericity of intraocular lenses (IOLs) on vertical coma aberration and higher-order aberrations (HOAs) and modulation transfer function (MTF) after phacoemulsification surgery and IOLs implantation.Methods:1、A total of116eyes of78patients were with IOLs implantation and3to4months after surgery was analyzed in this study,including31eyes with spherical IOL of Sensar AR40e,54eyes with aspheric aberration-free IOL of Akreos AO (29eyes)and Softec HD (25eyes) and31eyes with negatively aspheric IOL of Tecnis ZA9003. At postoperative follow-up visits, maximum pupil dilation was achieved and aberrometry was performed using an iTrace aberrometer with a pupil scan size of5.0mm.Data on vertical coma, horizontal coma, and spherical aberration were extracted.Tilt and decentration of the IOLs were measured using Scheimpflug photography (Pentacam,Oculus) and analyzed with Image-Pro Plus6.0software.2. A total of90eyes of69patients were with IOLs implantation and3to4months after surgery was analyzed in this study, including30eyes with spherical IOL of Acrysof SA60AT,30eyes with aspherically neutral IOL of Softec HD and30eyes negatively aspheric IOL of Acrysof SN60WF(IQ). At postoperative follow-up visits, HOAs and MTF at six spatial frequencies (5,10,15,20,25,30cpd) were measured in5.0mm pupil size.Tilt and decentration of the IOLs were measured using Scheimpflug photography(Pentacam,Oculus). The tilt and decentration, HOAs and subtracted lower order aberration MTF (MTF(HOA)) were compared. The effect of tilt and decentration on HOAs and MTF(HOA) was assessed using multiple regression analysis.Result:1、Vertical coma and spherical aberration values were highest with the spherical IOLs and lowest with the negatively aspheric IOLs (P=0.000and P=0.000, respectively). There was no difference in horizontal coma aberration among the4groups. There was no correlation between tilt or decentration and vertical coma aberration (P>0.05).2、No significant differences in IOL tilt or decentration were found (F=0.342,0.338; P=0.711,0.714).The spherical aberration in SA60AT group was largest and the differences were statistically significant (F=47.23,P=0.000). In5.0mm pupil size, MTF(HOA)at all spatial frequencies in SA60AT group were lowest and the differences were statistically significant (P<0.05). Tilt and decentration of the IOLs did not significantly affect HOAs and MTF.(HOA)Conclusion:1、Conventional spherical IOLs induce more vertical coma than aspheric IOLs and may help uncorrected near vision.2、Under normal conditions the amounts of tilt and decentration of IOLs in the lens capsule are small, the amounts of tilt and decentration of all IOLs are not large enough to affect the correction of spherical aberration and cause the deterioration of visual quality.