AIM: To measure the changes of ocular biological parameters before and after phacoemulsification, and compared the choice of intraocular lens(IOL)power calculation formulas based on the new optical biometric instrument IOL Master 700.

METHODS: A prospective study. Clinical data were collected from 52 patients(57 eyes)with cataract at the First Affiliated Hospital of Soochow University from January to June 2021. The axial length(AL), anterior chamber depth(ACD)and corneal curvature(Km)were measured and analyzed before and 3mo after phacoemulsification by IOL Master 700. The target refractive value reserved in the calculation of different IOL formulas and the actual refractive value of the automatic refractor 3mo after phacoemulsification were compared and statistically analyzed.

RESULTS: The average values of AL measured before and after phacoemulsification were 24.20±1.86, 24.09±1.86mm, the postoperative AL shortened by 0.11mm, and the ACD values were 3.08±0.44, 4.55±0.36mm(P<0.001), ACD deepened by 1.49mm after phacoemulsification. The Km values were 44.14±1.86, 44.14±1.82D(P>0.05). The refractive error of the results measured by the Barrett Universal Ⅱ formula was the smallest before operation, followed by Holladay Ⅱ and the SRK/T formula, the Holladay Ⅰ formula had the largest error and the difference was statistically significant(P<0.05).

CONCLUSION: The AL was shortened and the ACD was deepened after phacoemulsification. A correction factor of 0.1mm is suggested to add when calculating the degree. The Barrett Universal Ⅱ formula has the best predictability in the IOL power calculation formulas, follow by Holladay Ⅱ and SRK/T formula.