ObjectiveTo use ultrasound biomicroscope (UBM) to observe the zonules in patients before cataract surgery and study the relation between the length of zonules and axial length (AL), so as to understand the underlying anatomical and pathological basis of factors influencing the stability of lens capsule in high axial myopic patients and provide objective theoretical references for surgical risk reduction and postoperative follow-up guidance. MethodsFifty-five patients (55 eyes) proposed to receive phacoemulsification between October 2014 and October 2015 were divided into group A (AL < 26 mm, n=21), group B (26 mm≤AL < 29 mm, n=14), and group C (AL≥29 mm, n=20) according to their AL.UBM examination was conducted preoperatively.Through measuring the length of zonules in supine position at 12, 3, 6, and 9 o'clock respectively, we compared the difference of the length of zonules among those three groups, and explored the correlation between the length of zonules and axial length. ResultsThe average length of zonules in group A was (0.67±0.13) mm, while that in group B and group C was (0.93±0.29) and (0.98±0.19) mm, respectively.The length of zonules in group A was shorter than that in group B and Group C, and the differences were statistically significant (P < 0.001);and that in group B was shorter than that in group C, but the difference was of no statistical significance (P=0.331).In the correlation analysis between axial length and the average length of zonules, the length of zonules was positively correlated with the axial length (r=0.502). ConclusionsUBM provides a quantitative method for observing zonules.In the assessment before cataract surgery, it is a more accurate method for evaluation of zonules, and probably has a certain value in pre-assessment of intra ocular lens dislocation after cataract surgery.