AIM: To compare the differences and agreement of anterior segment biometric parameters of myopic patients measured by domestic Scansys and the imported Sirius based on the principle of Scheimpflug imaging technique.

METHODS: In this case series study, 103 cases(103 eyes)that underwent pre-refractive surgery(including small incision lenticule extraction, femtosecond laser-assisted in situ keratomileusis, transepithelial photorefractive keratectomy and implantable contact lens implantation)at Aier Excellent Eye Hospital from May 2022 to October 2022 were recruited. Preoperative keratometry(Km), central corneal thickness(CCT), anterior chamber depth(ACD_Endo.), anterior chamber angle(ACA), anterior chamber volume(ACV), white to white(WTW)of patients were recorded.

RESULTS: The results of Km, CCT, ACA, and WTW measured by Scansys and Sirius were 42.88(41.54, 44.60)and 42.98(41.56, 44.52)D,(541.52±29.08)and(549.55±29.62)μm, 42.70°±2.67° and 46.63°±5.13°, 12.10±0.60 and 11.98±0.47 mm, respectively, showing the difference was statistically significant(all P<0.01). The ACV measured by Scansys and Sirius was 194.26±31.06 and 191.47±25.65 mm³, and ACD_Endo. was 3.40(3.17, 3.57)and 3.43(3.19, 3.56)mm, with no statistically significant difference(all P>0.05). The range of Km, CCT, ACA, ACD_Endo., ACV and WTW values measured by the two instruments was small, with an average difference close to zero, and the points percentage of 95% limits of agreement(LoA)was <5%, which is of good consistency.

CONCLUSIONS: Scansys and Sirius have small differences and good agreement in the parameters, which can be replaced by each other in clinical practice. Scansys could theoretically be used to extrapolate the implantable contact lens model or could be a new option for anterior segment parameter measurements.