Impact Of Uncorrected Low Astigmatism On The Visual Quality Of Multifocal Pseudophakic Eyes

Purpose1. To Compare the agreement and difference of KR-1W and i Trace for measurement of high order aberrations, and make clear their working principle and practical application value in refractive cataract surgery. So as to find a suitable inspection equipment for cataract preoperative screening and postoperative study, which can provide scientific and accurate test results, and realize many checks in one,provide more convenienceand improve patient compliance, ensure the sustainability of clinical experiment research.2. To compare the postoperative virual effects of different low corneal astigmatism patients who had got cataract ultrasonic emulsification combined with Re STOR implantation. And evaluate the impact of low corneal astigmatism on visual quality of MIOL eyes.3. To compare visual quality between patients with a Acrysof IQ Restor Toric-2( ART2) IOL and those with a Acrysof IQ Restor(Re STOR) IOL, and investigate the predictability, efficacy, stability and safety of ART2 to correct the low corneal astigmatism.Methods1. KR-1W and i Trace were respectively used in a group of healthy people(40volunteers, 32eyes) to measure the high order aberration(HOA) of corneal,internal and total ocular. The clinical difference and agreement of two instruments were respectively evaluated by paired-samples t test and Bland-Altman analysis.2. According to the case selection criteria, 63 cases(80 eyes) simple age-related cataract patients were choosed in to study, who had got the cataract ultrasonic emulsification combined with multifocal lenses implantation. According to the preoperative corneal astigmatism, they were divided into two groups. There were35 eyes in group A, whose corneal astigmatism were lower than 0.75 D within-the-rule or lower than 0.5D against-the-rule. There were 45 eyes in group B, whose corneal astigmatism were ranged from 0.75 to 1.0D within-the-rule or ranged from 0.5 to 0.75 D against-the-rule. Three months postoperatively, the total range virual acuity and i Trace virual quality measurement were implemented. The results of UDVA, UIVA, UNVA, CDVA, CIVA, CNVA; the a MTF and SR; the spectacle independence; and patient satisfaction, were recorded to be analyzed.And the main influence factors of the virual results were analyzed withlinear-regression analysis.3. Cataract Eyes with regular corneal astigmatism 0.75 to 1.0D within the rule or0.5~0.75 D without the rule, received the cataract phacoemulsification and tne ART2 implantation. 17 eyes were chosed into the ART2 group( experimental group) according to the case selection criteria. Then multistage stratified random sampling acrroding to year and corneal astigmatism were used to choose the17 eyes into the control group, which cataract eyes had regular corneal astigmatism 0.75 to 1.0D within the rule or 0.5~0.75 D without the rule, and had received the cataract phacoemulsification and tne Re STOR implantation by the same surgical doctor. Each measurement of these eyes was repeated measured by the same equipment and the same physician. Outcome measures were uncorrected astigmatism(UA), spherical equivalent(SE); uncorrected entire visual acuities(UVA); distance corrected entire visual acuities(CVA); i Trace measurement including aberrations, a MTF, SR and the postoperative axis of ART2; spectacle independence; and patient satisfaction.Results1. The paired-samples t test showed that the corneal HOA measured by the two instruments had no statistical differences(P > 0.05); but the internal and total ocular HOA had significant statistical differences(P<0.05),and the mean results measured by i Trace were higher than that of KR-1W. However, Bland-Altman analysis revealed that the HOA of corneal and internal were all in 95% limits of agreement; and just one point of total ocular HOA was beyond the 95% limits of agreement.2. Three months potoperatively, the differences of the mean UA and the mean SE were significant statistically(P<0.05). The UVA and CVA of B group were bad than that of A group, and the differences were significant statistically(P<0.05).The a MTF and SR in B group were lower than A group, the differences were significant statistically in a MTF(P<0.05). And there were statistical differences in UVA, DCVA, a MTF, SR in different uncorrected astigmatism grades(P<0.05).The result of linear-regression analysis showed that the single influence factor of UDVA and spectacle independence is the corneal astigmatism(P < 0.05); the single influence factor of UIVA,UNVA,a MTF and SR; is the corneal astigmatism(P<0.05);but the single influence factor of uncorrected astigmatismwas corneal astigmatism(P < 0.05). The main influence factor of postoperative satisfaction was the pre-op expectation, UDVA and ratio of spectacle independence(P<0.05).3. The uncorrected astigmatism of ART2 group was close to the calculation results on line three months postoperatively, there were no statistical differences. The mean ART2 IOL axis rotation was 3.12±0.70 degrees. The mean UDVA 、UIVA and UNVA of ART2 group was(0.01±0.05)Log MAR、(0.05±0.07)Log MAR、(0.02±0.07)Log MAR respectively, better than that of Re STOR group, which respectively was 0.08±0.06 Log MAR、0.15±0.12 Log MAR�'�0.09±0.08 Log MAR,the differences were significant statistically(P<0.05). The UNVA of ART2 group were better than that of Re STOR group, the differences were significant statistically(P < 0.05). The a MTF and SR in ART2 group were higher than Re STOR group, the differences were not significant statistically(P>0.05). The subjective spectacle independence of ART2 and Re STOR group were 100% and82.35%, and the degree of dependence on glasses was less than 1/2 day.Conclusions1. KR-1W and i Trace were consistent well in the measurement of corneal, internal and total ocular HOA, especially for the cornea. And the i Trace is especially suitable for cataract study. As the cataract postoperative follow-up examine equipment, i Trace can provide accurate comprehensive data, improve patients postoperative obedience, and be conducive to clinical research and the improvement of surgical technique.2. The Re STOR MIOL patients can obtain good entire vision, visual quality, high rate of spectacle independence and postoperative satisfaction. The corneal astigmatism. is the main influence facor of entire vision, visual quality, spectacle independence and postoperative satisfaction of Re STOR MIOL eyes3. ART2 has a good predictability, effectiveness, stability and safety in the low astigmatism correction4. ART2 is more suitable for the cataract eyes with regular corneal astigmatism 0.75 to 1.0 diopter(D) within the rule or 0.5~0.75 diopter(D) without the rule, and can bring better visual results.