Purpose To assess the repeatability of measuring the corneal diameter (white-to-white, WTW) using Sirius and IOLMaster 700 in myopic eyes, to evaluate their consistency and relationship with sulcus-to-sulcus (STS) and angle-to-angle (ATA). Methods This retrospective study enrolled 58 volunteers with myopia (116 eyes). Each subject was evaluated using Sirius, IOLMaster 700 and ultrasound biomicroscope (UBM) for parameters which included WTW, STS, and ATA. STS referred to horizontal STS (STSH) and vertical STS (STSV), ATA contained horizontal ATA (ATAH) and vertical ATA (ATAV). The intra-device and intra-operator repeatability was assessed using the within-subject SD (Sw), precision, intrasession test-retest variability (repeatability), coefficient of variation (CoV), intraclass correlation coefficient (ICC) and Cronbach’s coefficient Alpha (CoA). Bland-Altman plots were used to analyze the agreement between WTW and STS/ATA at different meridians. The correlation among ocular parameters was assessed by Spearman correlation analysis. The ocular parameters with normal distribution were used to analyze the multiple linear regressions of STS at different meridians. Curve fitting was used to analyze the relationship between STS and WTW at different meridians, separately. Akaike information criterion (AIC), Bayesian information criterion (BIC) and adjusted coefficient of determination (adjusted R2) were used to assess Goodness of fit (GOF). Results Three repeated measurements of WTW by Sirius and IOLMaster 700 showed no statistically significant discrepancies between the data (F = 0.306; 2.469, P > 0.05), and the difference between the data of paired t-tests of the mean values of WTW measured by each instrument was statistically significant (t= -2.894, P < 0.01). The Sw, precision, repeatability, CoV, ICC, CoA values for WTW measured by Sirius and IOLMaster 700 were (0.027, 0.054, 0.076, 0.232%, 0.981, 0.993) and (0.079, 0.155, 0.219, 0.666%, 0.980, 0.993), respectively. This trial demonstrated by Bland-Altman plots that the 95% LoA (Limits of agreement) for concordance between WTW measured by Sirius (WTWS), WTW measured by IOLMaster 700 (WTWI), STSH, STSV, ATAH and ATAV were beyond clinically acceptable limits. WTWS and WTWI had a moderate negative correlation with Kf (r=-0.39;-0.45, P<0.01) and Ks (r=-0.38;-0.39, P<0.01). Inversely, WTWS and WTWI had a weak to moderate positive correlation with ACD(r = 0.33, P<0.01; r = 0.20, P<0.05), AL(r = 0.25; 0.35, P<0.01), STS(P<0.01) and ATA(P<0.01) at different meridians, WTWS had a high positive correlation with WTWI (r = 0.76, P<0.01). Similarly ATAH had a high positive correlation with ATAV (r = 0.76, P<0.01). Through multiple linear regression analysis, the prediction equation of STSH was STSH=7.098- 0.357xSE+0.281xACD-0.201 xKf+0.307xWTWS, the prediction equation of STSV was STSV=7.710-0.289xIOP-0.336xSE+0.359xACD-0.203xKf+0.263xWTWS, the Adj. R2 were 0.391 and 0.423, respectively. The linear equation between STSH and STSV was STSV=2.765+0.804xSTSH, and the Adj. R2 was 0.486. The curve fitting suggested that the optimal curve model between WTWS and STSH was Logistic (AIC=-161.622, BIC=-148.399 and Adj. R2=0.226), the optimal curve model between WTWI and STSH was also Logistic (AIC=-153.969, BIC=-140.747 and Adj. R2=0.174), the curve fit between WTW and STSV was poor, the optimal curve model between STSH and STSV was Extreme (AIC=-180.337, BIC=-167.115 and Adj. R2=0.501). Conclusion The repeatability of WTW measured by Sirius and IOLMaster 700 was satisfactory. The WTW measured by IOLMaster 700 was bigger than the WTW measured by Sirius. The parameters of WTWS, WTWI, STSH, STSV, ATAH and ATAV were inconsistent with each other, they were not clinically interchangeable. Using WTWS and WTWI to predict STSH may be more appropriate for categorical studies. It was recommended to use vertical corneal diameter to study STSV.

Repeatability of corneal diameter measured by Sirius versus IOLMaster 700 in myopic eyes: combined with consistency and relationship of sulcus-to-sulcus

期刊论文
发表日期：

2026年5月23日

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Xin Xu,
Peng Yu,
Shuai Wu,
Lei Wang,
Qing Li,
Duo Peng

摘要

Purpose

To assess the repeatability of measuring the corneal diameter (white-to-white, WTW) using Sirius and IOLMaster 700 in myopic eyes, to evaluate their consistency and relationship with sulcus-to-sulcus (STS) and angle-to-angle (ATA).

Methods

This retrospective study enrolled 58 volunteers with myopia (116 eyes). Each subject was evaluated using Sirius, IOLMaster 700 and ultrasound biomicroscope (UBM) for parameters which included WTW, STS, and ATA. STS referred to horizontal STS (STS_H) and vertical STS (STS_V), ATA contained horizontal ATA (ATA_H) and vertical ATA (ATA_V). The intra-device and intra-operator repeatability was assessed using the within-subject SD (Sw), precision, intrasession test-retest variability (repeatability), coefficient of variation (CoV), intraclass correlation coefficient (ICC) and Cronbach’s coefficient Alpha (CoA). Bland-Altman plots were used to analyze the agreement between WTW and STS/ATA at different meridians. The correlation among ocular parameters was assessed by Spearman correlation analysis. The ocular parameters with normal distribution were used to analyze the multiple linear regressions of STS at different meridians. Curve fitting was used to analyze the relationship between STS and WTW at different meridians, separately. Akaike information criterion (AIC), Bayesian information criterion (BIC) and adjusted coefficient of determination (adjusted R²) were used to assess Goodness of fit (GOF).

Results

Three repeated measurements of WTW by Sirius and IOLMaster 700 showed no statistically significant discrepancies between the data (F = 0.306; 2.469, P > 0.05), and the difference between the data of paired t-tests of the mean values of WTW measured by each instrument was statistically significant (t= -2.894, P < 0.01). The Sw, precision, repeatability, CoV, ICC, CoA values for WTW measured by Sirius and IOLMaster 700 were (0.027, 0.054, 0.076, 0.232%, 0.981, 0.993) and (0.079, 0.155, 0.219, 0.666%, 0.980, 0.993), respectively. This trial demonstrated by Bland-Altman plots that the 95% LoA (Limits of agreement) for concordance between WTW measured by Sirius (WTW_S), WTW measured by IOLMaster 700 (WTW_I), STS_H, STS_V, ATA_H and ATA_V were beyond clinically acceptable limits. WTW_S and WTW_I had a moderate negative correlation with Kf (r=-0.39;-0.45, P<0.01) and Ks (r=-0.38;-0.39, P<0.01). Inversely, WTW_S and WTW_I had a weak to moderate positive correlation with ACD(r = 0.33, P<0.01; r = 0.20, P<0.05), AL(r = 0.25; 0.35, P<0.01), STS(P<0.01) and ATA(P<0.01) at different meridians, WTW_S had a high positive correlation with WTW_I (r = 0.76, P<0.01). Similarly ATA_H had a high positive correlation with ATA_V (r = 0.76, P<0.01). Through multiple linear regression analysis, the prediction equation of STS_H was STS_H=7.098-

0.357xSE+0.281xACD-0.201 xKf+0.307xWTW_S, the prediction equation of STS_V was STS_V=7.710-0.289xIOP-0.336xSE+0.359xACD-0.203xKf+0.263xWTW_S, the Adj. R² were 0.391 and 0.423, respectively. The linear equation between STS_H and STS_V was STS_V=2.765+0.804xSTS_H, and the Adj. R² was 0.486. The curve fitting suggested that the optimal curve model between WTW_S and STS_H was Logistic (AIC=-161.622, BIC=-148.399 and Adj. R²=0.226), the optimal curve model between WTW_I and STS_H was also Logistic (AIC=-153.969, BIC=-140.747 and Adj. R²=0.174), the curve fit between WTW and STS_V was poor, the optimal curve model between STS_H and STS_V was Extreme (AIC=-180.337, BIC=-167.115 and Adj. R²=0.501).

Conclusion

The repeatability of WTW measured by Sirius and IOLMaster 700 was satisfactory. The WTW measured by IOLMaster 700 was bigger than the WTW measured by Sirius. The parameters of WTW_S, WTW_I, STS_H, STS_V, ATA_H and ATA_V were inconsistent with each other, they were not clinically interchangeable. Using WTW_S and WTW_I to predict STS_H may be more appropriate for categorical studies. It was recommended to use vertical corneal diameter to study STS_V.