AIM:To evaluate the accuracy of A-ultrasound combined with corneal topography measurement in clinical application by analyzing the ocular-related biometric parameters and refractive error and comparing with those of IOL Master 700 in cataract patients.

METHODS: A prospective study. Clinical data were collected from 113 patients(122 eyes)who underwent phacoemulsification in the First Affiliated Hospital of Soochow University from July 2020 to July 2021. The axial length(AL), anterior chamber depth(ACD), lens thickness(LT)and corneal curvature(Km)were measured respectively by IOL Master 700 and A-ultrasound combined with corneal topography measurement and the 3mo after the surgery of the refractive error was analyzed.

RESULTS: There were differences in AL(24.09±1.65, 23.81±1.62mm), ACD(3.11±0.42, 2.97±0.43mm)and Km(44.12±1.59, 44.06±1.54D)measured by IOL Master 700 and A-ultrasound combined with corneal topography(P<0.05), while there was no difference in LT(4.34±0.46, 4.30±0.59mm)(P>0.05). The postoperative mean absolute refractive error(MAE)of intraocular lens(IOL)diopter calculation formulas with different measurement methods was significantly different(P<0.001). The Barrett Universal II formula MAE of the IOL Master 700 measuring instrument was different from the Holladay I, Haigis and SRK/T formulas(P<0.01), at the same time, compared with the A-ultrasound combined with corneal topography calculation formula SRK/T and Barrett Universal II formula, they were also different(P<0.01). However, there was no difference among the Holladay Ⅰ, Haigis, SRK/T formula MAE which come from the IOL Master 700 measuring instrument and the A-ultrasound combined with corneal topography calculation formula SRK/T formula(P>0.05). In addition, the Barrett Universal II formula of the IOL Master 700 measuring instrument has the smallest median absolute refractive error(MedAE)(0.260D), and the A-ultrasound combined with corneal topography calculation formula Barrett Universal II formula MedAE is the largest(0.765D).

CONCLUSION: The values of AL, ACD and Km measured by A-ultrasound combined with corneal topography were smaller than those of IOL Master 700. When the SRK/T formula was used to calculate the IOL diopter, the results of the two group were similar. However, when using the Barrett Universal Ⅱ formula, the refractive error of the A-ultrasound combined with corneal topography group was large, resulting in hyperopia drift.