AIM: To quantitatively assess the influence of pars plana vitrectomy(PPV)on the length of lens zonules and anterior chamber depth(ACD).

METHODS: The medical records of 87 cataract patients(88 eyes)were retrospectively reviewed. Forty-three patients(44 eyes)with previous PPV were included in the study group, and 44 patients(44 eyes)without a history of PPV were served as control group. Length of zonules and anterior chamber depth(ACD)were quantitative analyzed based on the data from ultrasonic biomicroscopy(UBM)and IOL Master examinations respectively.

RESULTS: The average length of zonules in study and control group were 1.09±0.24mm and 0.78±0.22mm, respectively, and the difference was statistically significant(P<0.05). The ACD of the two groups were 3.25±0.39mm and 3.44±0.48mm, respectively, and a statistical difference was observed(P<0.05). The length of zonules in the control group was positively correlated with the ACD(r=0.468, P=0.001), however, this was not the case in the study group(r=0.173, P=0.263).

CONCLUSION: Previous vitrectomy may cause changes in zonular length, which may imply a possibly weakened zonules, especially for patients with the axial length less than 29mm. The change in anterior chamber depth in patients with previous PPV may not be correspondent to that in the length of zonules. The findings of our study suggest that preoperative conditions of zonules and anterior chamber should be fully understood to reduce the related complications and to improve the safety and efficiency of cataract surgery after pars plana vitrectomy.