Consistency between MT-9000 and IOLMaster 700 in measuring ocular biometric parameters in cataract eyes

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Objective  To analyze the consistency between MT-9000 and IOLMaster 700 in measuring preoperative ocular biometric parameters in patients with age-related cataracts.

Methods  A cross-sectional study was conducted.A total of 536 patients (536 eyes) were consecutively included and scheduled for cataract extraction combined with intraocular lens implantation at Aier Eye Hospital of Wuhan University from June 20 to August 22, 2024.Two visualized sweep-frequency biometers, MT-9000 and IOLMaster 700, were used to measure the biometric parameters of all the patients.The parameters including axial length (AL), white to white (WTW), anterior chamber depth (ACD), lens thickness (LT), central corneal thickness (CCT), and mean keratometry (Km). The AL detection rates of the two instruments were compared, as were the differences in above parameters, and the correlation and consistency of the measurements were analyzed.Patients were divided into three groups based on AL measured by MT-9000: a short axis group (AL<22 mm) comprising 27 eyes, a normal axis group (22≤AL≤25 mm) comprising 392 eyes, and a long axis group (AL>25 mm) comprising 104 eyes.The differences in measured AL in different subgroups were compared.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Aier Eye Hospital, Wuhan University (No.2024IRB06017). Written informed consent was obtained from each subject.

Results  The AL detection rate measured by MT-9000 was 99.3% (532/536), higher than 97.6% (523/536) measured by IOLMaster 700, with a statistically significant difference ( χ ²=4.841, P=0.028). MT-9000 AL, LT and Km measurements were all higher than IOLMaster 700 measurements, showing statistically significant differences ( Z=6.418, t=4.971, 5.179; all P<0.001). WTW and CCT measurements from MT-9000 were both lower than those from IOLMaster 700, showing statistically significant differences ( Z=-3.017, t=16.322; both P<0.05). After grouping based on AL measurements from MT-9000, there was no statistically significant differences in AL measurements between MT-9000 and IOLMaster 700 in the short axis group and the normal axis group ( Z=-1.530, P=0.126; t=-0.880, P=0.380). In the long axis group, the AL measured by MT-9000 was longer than that by IOLMaster 700, with a statistically significant difference ( Z=7.254, P<0.001). The intra-class correlation coefficient values of AL, WTW, ACD, LT, CCT, and Km measured by MT-9000 and IOLMaster 700 were 1.000, 0.616, 0.997, 0.999, 0.988, and 0.995 (all P<0.001), respectively.The 95% limits of agreement (LoA) of AL, WTW, ACD, LT, CCT, and Km measured by Bland-Altman analysis were -0.06-+ 0.08 mm, -0.64-+ 0.57 mm, -0.06-+ 0.06 mm, -0.04-+ 0.05 mm, -13.6-+ 6.3 μm and -0.26-+ 0.32 D, respectively, which had 6.5%, 3.6%, 5.3%, 6.3%, 6.5% and 4.4% of the data points outside the 95% LoA.

Conclusions  MT-9000 shows favorable agreement with IOLMaster 700 in the measurement of AL, ACD, LT, CCT and Km.MT-9000 is suitable for preoperative biometrics measurement in cataract patients.However, the agreement between the two devices is not desirable in the measurement of WTW, and interchangeable use of these two devices is not recommended in this regard.Additionally, MT-9000 outperforms IOLMaster 700 in terms of AL detection rate.

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