Study Of Tilt And Decentration Of Different Designed Intraocular Lens And The Change Of Modulation Transfer Functions In Them

Objective:To compare tilt and decentration of different lens and modulation transfer function(MTF) caused by different intraocular lens's(IOL) tilt after phacoemulsification and intraocular lens implanted in the bag.Methods:A retrospective clinical case series study.112 eyes of 112 patients with senile cataract were examined two months after phacoemulsification and intraocular lens implantation The age range (50-75) years.According to types of intraocular lens we divided into ZA9003 (negative aberrtionl),AR40E (positive aberration) and ADAPT-AO(O aberration). The patients were followed up and dilated to 8mm 2 months later and their decentration and tilt of the IOLs were quantified using a video photography system (Pentcam, Oculus) and image-analysis. The inter MTF at 5,10,15,20,25,30 (c/d) spatial frequencies were measured by iTrace application under 5mm pupil size. According to the class wides of 0.5°of tilts we divided the tilt and decentration into three groups:small tilt,middle tilt and big tilt.At first, we analysed the correlation between tilt and decentrtion.Then, among the three groups of each IOL,we compare the differences of decentration and tilt and MTF at all spatial frequencies which corresponding to them with ANOVA. We also compare the visual quality caused by different tilt of the three type IOLs with kolmogorov-smirnovz test after doing central adjustment. At last, we compare the MTF at all spatial frequencies under 5mm pupil size among the three trpe IOLs with ANOVA.82 eyes of 82 patients with senile cataract were examined two months after phacoemulsification and intraocular lens implantation. Among which we implanted three-into one piece IOL(PY-60AD) and three pieces IOL(ZA9003). The patients were dilated to 8mm and their decentration and tilt of the IOLs were quantified using a video photography system (Pentcam, Oculus) and image-analysis. T-test was used to analyze the date.Results:The correlation between IOLs'tilt and decentration was not significant(r=0.183,P=0.051). The mean tilt of ZA9003,AR40E,ADAPT-AO were (0.93±0.71)°,(1.12±0.73)°,(0.76±0.51)°.Meantime the mean decentration were (0.13±0.10)mm,(0.18±0.12)mm, (0.13±0.08)mm, there were no significant difference(P> 0.05). The mean tilt of the three groups of ZA9003 were(0.28±0.15)°,(0.78±0.12)°,(1.67±0.60)°; The mean tilt of the three groups of AR40E were(0.38±0.20)°,(0.71±0.12)°,(1.77±0.56);The mean tilt of the three groups of ADAPT-AO were(0.31±0.16)°,(0.66±0.17)°,(1.40±0.39)°there were significant differences among the tilt of the three groups of each IOL (P< 0.05).The mean decentration the three groups of ZA9003 were(0.09±0.05)mm, (0.11±0.08) mm,(0.16±0.12)mm. and the mean decentration of AR40E were(0.15±0.06)mm, (0.13±0.15)mm,(0.16±0.08)mm, the mean decentration of ADAPT-AO were (0.13±0.06)mm. (0.14±0.15)mm. (0.13±0.08)mm, There were no significant differences among the decentration of the three groups of each IOL (P> 0.05).There was no significant difference in MTF of all spacial frequency corresponding to the different tilt groups of each IOL under 5mm pupil size(P> 0.05). After doing central adjustment of the MTF of each groups of the two IOLs, there were no significant difference(p>0.05)between ZA9003 and AR40e in small tilt group and middle tilt group.Tthere were significant difference(P< 0.05)in big tilt group at the spatial frequencies of 20 and 25,but not in the other spatial frequencies. There were significant difference in MTF at all spacial frequency among the three type IOL under 5mm pupil size(P< 0.05).And There were significant difference in MTF at all spacial frequency beteewn ZA9003and AR40E,ADAPT-AO (P< 0.05) but not between AR40E and ADAPT-AO(P> 0.05).In big pupil size,the mean tilt of PY-60AD and ZA9003 were (0.81±0.62). (0.93±0.71) and the mean decentration of them were (0.11±0.09). (0.13±0.10).There were no significant difference between them (P=0.478,0.637)Conclusion:With the modern technique, In negative aberation IOL the visual quality changes caused by the big tilt at some spatial frequencies is more sensitive than in positive aberration and 0 aberrtion IOL,but positive aberration and 0 aberrtion IOL are similar. However, the tilt of all types IOLs can not change the visual quality significantly. Three-into one piece and three pieces IOL have similar stability after they were impalanted in the bag under big pupil size.