Abstract:AIM: To investigate the repeatability of using IOL Master 700 to stratify corneal astigmatism and related biological parameters in cataract patients with different degrees of astigmatism, and evaluate its consistency with IOL Master 500.
METHODS: A cross-sectional study was conducted on preoperative cataract patientsadmitted to the hospital from February 2024 to September 2025. The patients were divided into three groups: low astigmatism group(astigmatism<0.75 D), moderate astigmatism group(0.75 D≤astigmatism≤1.50 D), and high astigmatism group(astigmatism>1.50 D). The IOL Master 700 and IOL Master 500 biometers were used by the same examiner respectively. Under the same environment, head position, and operating standards, each eye was continuously measured twice(with an interval of 3-5 min)with each instrument. Axial length(AL), anterior chamber depth(ACD), lens thickness(LT), corneal transverse diameter(WTW), flat curvature(Kf), steep curvature(Ks), mean curvature(Km), anterior corneal astigmatism(Kly), total corneal astigmatism(TK), iris-based diameter-vertical component(IBD-Ix), iris-based diameter-horizontal component(IBD-Iy)and astigmatism vectors J0 and J45 were recorded. Intraclass correlation coefficient(ICC)was used to evaluate the repeatability of IOL Master 700 measurements. Bland-Altman 95% limits of agreement(LoA)was used to evaluate the consistency of IOL Master 700 and IOL Master 500 measurements. Correlation scatter plots were used to evaluate the correlation between IOL Master 700 and IOL Master 500 measurements.
RESULTS:Totally 238 preoperative cataract patients(238 eyes)were selected as the research subjects and divided into a low astigmatism group of 88 cases, including 47 males and 41 females, with an average age of 68.14±6.25 y. The moderate astigmatism group consisted of 80 eyes, with 42 males and 38 females, with an average age of 68.13±6.98 y. The high astigmatism group consisted of 70 eyes, with 38 males and 32 females, with an average age of 69.11±6.79 y. The general information of the three groups of patients was comparable. In the low, medium, and high astigmatism groups, the ICC measured by IOL Master 700 for AL, ACD, LT, WTW, Kf, Ks, Km, Kly, TK, and IBD-Ix were all>0.90, and the ICC for IBD-Iy was>0.85. The ICC comparison of J0 and J45 patients with different degrees of astigmatism showed that the low astigmatism group was less than the moderate astigmatism group and less than the high astigmatism group. Bland Altman analysis between two devices showed that the 95% LoA width of AL, ACD, LT, WTW, Kf, Ks, Km, Kly, TK, and IBD-Ix was narrow, indicating good consistency between the two instruments. For the astigmatism vectors J0 and J45, the Bland Altman 95% LoA width between the two devices decreased with increasing astigmatism. A correlation scatter plot was drawn, which showed that the scatter points of AL, ACD, LT, WTW, Kf, Ks, Km, Kly, TK, IBD-Ix, and IBD-Iy were closely clustered on both sides of the diagonal without obvious outliers, indicating high correlation. J0 and J45 scatter points were still distributed along the diagonal, but the degree of dispersion was significantly greater than the above parameters, indicating slightly lower correlation.
CONCLUSION:IOL Master 700 exhibits goodtoexcellent repeatability in measuring parameters such as AL, ACD, LT, WTW, corneal curvature, Kly, TK, IBD-Ix,and IBD-Iy in cataract patients with different degrees of astigmatism, and shows good agreement with the IOL Master 500. However, for the astigmatism vectors J0 and J45, the repeatability of IOL Master 700 and its consistency with IOL Master 500 both decrease with decreasing astigmatism, and the difference is particularly significant in patients with low astigmatism. Therefore, astigmatism vector outcomes obtained from a single measurement should be interpreted with caution in patients with low astigmatism.
