Correlation Analysis Between Anterior Segment Changes And Refractive Shift After Cataract Phacoemulsification

Objective:To quantify the changes in the corneal curvature(Km),anterior chamber volume(ACV),anterior chamber depth(ACD)and anterior chamber angle(ACA)in the patients after phacoemulsification by Pentacam system,and analyze the correlation between anterior segment changes and refractive shift.Methods:Km,ACV,ACD and ACA were measured in 40 cataract patients(42 eyes)before phacoemulsification and 1 day,1 week,1 month after phacoemulsification by Pentacam system,and refraction were recorded by optometry.The data were statistically analyzed by using ANOVA for repeated measurement,one-sample t-test and Pearson linear correlation.Results:By optometry,it was showed that the average refraction was(-0.43 ±0.50)D at 1 day after surgery,(-0.71 ±0.54)D at 1 week after surgery,(-0.50 ±0.46)D at 1 month after surgery.The diopter at 1 day after surgery was closed to the target diopter(-0.5D),while there were statistically significant increases of the degree of the myopia at 1 week after surgery.When 1 month after surgery,the diopter was closed to the target diopter again,where there was no statistically significant difference with the diopter 1 day after surgery(P?0.05).Pentacam system showed that the average ACD was(3.99 ±0.53)mm at 1day after surgery,(3.81 ±0.50)mm at 1 week after surgery,(3.53 ±0.38)mm at1 month after surgery;the average ACV was(152.05 ±26.75)mm3 at 1 day after surgery,(139.71 ±26.65)mm3 at 1 week after surgery,(127.83 ±25.37)mm3 at1 month after surgery;the average ACA was(45.44 ±6.45)°at 1 day after surgery,(43.83 ±5.81)°at 1 week after surgery,(43.82 ±4.58)°at 1 month after surgery.There was statistically significant decrease between 1 week ? 1month and the first day after surgery in the ACD and ACV(all P?0.05),but there wasn't statistically significant difference between 1 week?1 month and the first day after surgery in the ACA(P ? 0.05).The average Km was(42.74 ±1.06)before surgery,(42.75 ±1.05)at 1 day after surgery,(42.73 ±1.00)at 1week after surgery,(42.73 ±1.01)at 1 month after surgery,there wasn't statistically significant difference in patients before and after surgery(P ?0.05).Compared with the 1 day after surgery,the changes of diopter of 1week ? 1 month after surgery was(-0.28 ± 0.60)D and(-0.07 ± 0.68)D.The positive correlation was found between the changes of diopter and changes of ACD(r1?=0.73,r1?=0.83,all P?0.05),also between the changes of diopter and changes of ACA at 1 week after surgery(r1?=0.31,P?0.05),but not found at the1 month(P?0.05).There was no statistically significant correlation between the changes of diopter and the changes of ACV,neither the changes of Km(all P?0.05).Conclusion:The phenomenon of early refractive shift may exist in the cataract patients whose diopter of 1 day after surgery was closed to the target diopter,then became myopic shift,finally decrease at 1 month after surgery.The early refractive shift is closely related with the changes of ACD.