Comparison Of Biometry Measurements Between Two Swept-Source Optical Coherence Tomopgraphy Biometers

This study aims to assess the agreement in measurements between two swept-source optical coherence tomography biometry devices: the IOLMaster 700 and Eyestar 900.

Tan Tock Seng Hospital, Singapore

100 eyes of 82 patients undergoing cataract surgery were included in this retrospective comparative study. All patients were evaluated with the IOLMaster 700 (Carl Zeiss Meditec AG) and the Eyestar 900 (Haag-Streit Diagnostics). Axial length (AL), anterior chamber depth (ACD), lens thickness (LT), anterior and posterior keratometry (AK and PK), central corneal thickness (CCT) and white-to-white (WTW) were measured. Difference in measured parameters between the two devices was assessed with a two-sample t-test, correlation was assessed with Pearson's or Spearman's correlation coefficient, and Hotelling's T² test was used to assess the difference between anterior corneal astigmatism values and posterior corneal astigmatism values.

There were no significant differences in AL (p = 0.77), ACD (p = 0.50), LT (p = 0.31), average anterior keratometry (p = 0.84) or CCT (p = 0.37) values between the two devices. There was a strong correlation between parameters measured with the two devices (AL, r_s = 0.95; ACD, r = 0.97; LT, r = 0.97; AK, r = 0.97, CCT, r = 0.98). However, there were statistically-significant differences between average posterior keratometry (p < 0.01) and WTW (p < 0.01). Hotelling's T² test demonstrated a significant difference between IOLMaster 700 and Eyestar 900 posterior corneal astigmatism values (p < 0.01), but not between anterior corneal astigmatism values (p = 0.98).

Posterior keratometry values are not interchangeable between the two studied SS-OCT devices. While the difference between these measurements is statistically-significant, the clinical significance is unknown. This warrants further investigation.