AIM: To analyze the correlation and agreement of corneal horizontal diameter(WTW)measured with caliper, IOL Master and Oculyzer anterior segment analysis system.

METHODS: Totally 41 patients with 80 eyes who underwent ICL V4c implantation in our hospital from July 2018 to January 2019 were enrolled. Compare the correlation and agreement of preoperative WTW measured with caliper, IOL Master and Oculyzer anterior segment analysis system respectively.

RESULTS: The mean WTW value measured with caliper, IOL Master and Oculyzer anterior segment analysis system were: 11.73±0.40, 12.03±0.46, 11.54±0.39mm respectively, the value of caliper and IOL Master, caliper and Oculyzer, IOL Master and Oculyzer were highly correlated(r=0.809, 0.826, 0.785, all P<0.01), and the 95% LoA of Bland-Altman analysis were(-0.84, 0.22),(-0.27, 0.64),(-0.07, 1.05)mm respectively.

CONCLUSION: Among the three measuring instruments, IOL Master has the largest measurement value and Oculyzer is the smallest. The three measurement methods have poor consistency and cannot be replaced in clinical application. Whereas, their measurements are highly correlated. In clinical application, the measurements of IOL Master and Oculyzer can be corrected based on the difference with caliper.