AIM:To study the variation of ocular biometric parameters and their relationship before and after phacoemulsification in cataract patients with over-long axial length.

METHODS:A total of 44 cases(61 eyes)were collected from September 2013 to March 2015 in Xuanwu Hospital which had underwent phacoemulsification and intraocular lens(IOL)implantation. The study contained 29 eyes of 20 patients with over-long axial length and 32 eyes of 24 patients with normal axial length. Before cataract surgery, the optical biometric measurements had been measured by IOL Master. And 3mo after surgery, the ocular biometric parameters had been recorded by IOL Master and ultrasound biomicroscopy(UBM). The changes and correlation of biometric parameters was performed using the SPSS software(version 17.0).

RESULTS: Pearson correlation analysis showed there was no correlation between postoperative anterior chamber depth and age, preoperative axial length, or preoperative corneal curvature in over-long axial length group(P>0.05). There was a positive correlation between the postoperative anterior chamber depth and the preoperative anterior chamber depth(r=0.402, P=0.031). Compared with the preoperative biometric parameters in over-long axial length group, axial length shortened, corneal curvature increased, anterior chamber depth deepened after surgery, and the difference was statistically significant(P<0.05). However, in the normal axial control group there was no correlation between the postoperative anterior chamber depth and age, preoperative axial length, or preoperative anterior chamber depth(P>0.05). There was a positive correlation between the postoperative anterior chamber depth and the preoperative corneal curvature(r=0.538, P=0.001). And in normal axial control group, the axial length was significantly shorter than that before surgery(P<0.05). The anterior chamber depth was significantly increased compared with the preoperative(P<0.05), and the corneal curvature was unchanged(P>0.05). The percent change of corneal curvature was statistically significant between two groups(P<0.05), and the percent change of corneal curvature in over-long axial length group was bigger than normal axial length group. There was no significant difference in the percent change of axial length and anterior chamber depth(P>0.05).

CONCLUSION: In cataract patients with over- long axial length, postoperative axial length shortened, and postoperative corneal curvature increased. A certain number of degrees should be added when calculating the degree of intraocular lens in order to obtain better postoperative visual acuity. The prediction of postoperative anterior chamber depth in cataract patients with over-long axial length has complexity and unpredictability of individual differences, and requires further research.