Observation of visual quality and the feasibility of using two different principle instruments to guide intraocular lens implantation for personalized spherical aberration

Abstract

Objective To compare visual quality after using an iTrace Aberrometer or Pentacam system to guide personalized aspheric intraocular lenses (IOLs) implantations; to discuss the feasibility of using the 2 instruments to guide IOL implantation or whole eye spherical aberrations About +0.1 μm.Methods This was a prospective clinical study.One day before phacoemulsification and aspheric IOL implantation surgery,a Pentacam or iTrace aberrometer was used to measure corneal spherical aberrations (Z40) under a 6 mm pupil diameter of patients with age-related cataract.Fifty-five patients (58 eyes were divided into an iTrace group (31 eyes) and a Pentacam group (27 eyes).Tecnis IOLs,AcrySof IQ IOLs or ADAPT-AO IOLs were implanted in these patients based on the measurement results so that the patient's predictive value of the whole eye spherical aberration was in the range of 0.05-0.15 μm after surgery.After 3 months,uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),modulation transfer function (MTF) for less than a 6 mm pupil diameter,spherical aberrations of the whole and inside eye were measured.The relevant data were analyzed using a paired t test and independent samples t test.Results ① After surgery,the UCVA and BCVA were compared for the 2 groups.The differences were not statistically significant (UCVA:t=0.83,P＞0.05; BCVA:t=0.37,P＞0.05).② All predicted preoperative whole eye spherical aberrations under a 6 mm pupil diameter were compared to +0.1 μm for the 2 groups.The differences were not statistically significant (iTrace group:t=-1.70,P＞0.05; Pentacam group:t=0.64,P＞0.05).After surgery,the actual spherical aberrations of the 2 groups under a 6 mm pupil diameter were compared to +0.1 μm.The difference for the iTrace group was not statistically significant (t=0.58,P＞0.05),but there was a statistically significant difference for the Pentacam group (t=2.33,P＜0.05).③The difference in the predicted values of the preoperative spherical aberrations of the whole eye and the actual values after surgery were not statistically significant (iTrace group:t=-1.55,P＞0.05; Pentacam group:t=-2.04,P＞0.05).The actual spherical aberrations of the inside eye after surgery vs.spherical aberrations of IOLs and the differences were not statistically significant (iTrace group:t=-1.55,P＞0.05 ; Pentacam group t=0.73,P＞0.05).The difference between the 2 groups'actual values of the spherical aberrations of the whole eye was not statistically significant (t=1.52,P＞0.05).④After surgery,under a 6 mm pupil diameter at 5,10,15,20,25 and 30 cycles per degree (c/d) spatial frequencies,the differences in the values of the MTFs of higher-order aberration between the 2 groups were not statistically significant (t=0.88,0.47,0.34,0.02,-0.57,-0.23,P＞0.05) and the differences in the values of the MTFs of sphcrical aberration for the 2 groups were not statistically significant (t=-0.37,-0.46,-0.43,-0.39,-0.68,-1.08,P＞0.05).Conclusion The 2 groups that underwent 2 different instrument-guided aspheric IOL implantations can achieve satisfactory targets for spherical aberrations.The iTrace group's predictive value is closer to the actual value than the Pentacam group's.Aspheric IOL implantation surgery guided with either instrument can achieve good postoperative visual quality. Key words: Pentacam ; iTracc ; Phacoemulsification ; Intraocular lens aspheric ; Spherical aberration; Modulation transfer function