Abstract:  Objective To compare the accuracy of 4 intraocular lens calculation formulas in the prediction of postoperative refraction in cataract patients with normal or nearly normal axial lengths (AL) but shallow anterior chamber depths (ACD). Design Retrospective case series. Participants A total of 66 cataract patients (86 eyes) with AL 22~25 mm but shallow and deep ACD in Beijing Tongren Hospital from December 2020 to August 2021. Methods All patients were performed cataract surgery with IOLMaster 500 optical biometry. Preoperative and postoperative ACD were measured. Manifest refraction was performed at 3-month postoperative visit. The performance on 4 formulas with respect to the error in predicted spherical equivalent was compared. Main Outcome Measures The mean prediction errors, mean absolute errors (MAE), median absolute errors and percentage of eyes with refractive prediction errors. Results At 3 months after surgery, the mean postoperative ACD (3.88±0.61 mm) was deeper than preoperative ACD (2.34±0.14 mm) (P<0.001). All formulas had mean prediction error values less than ±0.25 D that were not significantly different. There was no significant difference between Barrett (0.033 D) and Kane formula (-0.040 D) in the mean prediction errors. There was no significant difference in MAE between Barrett and Haigis formula (P=0.073), and between Barrett and Kane formula (P=1.000). The differences between the other formulas were statistically significant. Haigis formula had a highest percentage of eyes (30.23%) within the range of ±0.25 D, while Barrett formula had the highest percentage (60.47%) in the range of ±0.50 D. There were no significant differences between other formulas. Conclusion In eyes with normal or nearly normal AL but shallow ACD, modern biometric technology and new-generation formulas improved refractive prediction results. （Ophthalmol CHN, 2022, 31: 114-117）

Key words:  anterior chamber depth, refractive error, axial length, intraocular lens, cataract