Comparison Of Anterior Segment Measurements With Multiple Devices And A New Multifunctional Unit For Preoperative Examination Of Cataract Surgery

For preoperative examination of cataract surgery, accurate measurements of ocular anterior segment are important. Various devices for anterior ocular biometry are used for preoperative measurement. However, there is controversy on which devices should be used for accurate preoperative examination for cataract surgery. In addition, as the release of new devices have continued, it is necessary to evaluate the correlation and agreement between the devices for reliable use. To evaluate the clinical availability of a new multifunctional ocular biometric unit, MR-6000 (Tomey Corporation, Nagoya, Japan), for simultaneous keratometry, tonometry, topography, and pachymetry evaluation, comparing anterior segment measurements with five other devices.

Thirty patients (30 eyes) who visited our clinic for cataract surgery were examined using MR-6000 and the other devices: autokeratometer (KR-1, Topcon, Tokyo, Japan), Scheimpflug camera (Pentacam HR, Oculus, Wetzlar, Germany), swept-source optical coherence tomography (IOLMaster 700, Carl Zeiss, Oberkochen, Germany), Placido disk scanning-slit topography (Orbscan II, Bausch & Lomb, NY, USA), and noncontact tonometry (FT-1000, Tomey Corporation).

With above six different devices, the mean keratometry (K_m), central corneal thickness (CCT), white-to-white (WTW) distance, and intraocular pressure (IOP) values were measured and compared. In comparing keratometry, MR-6000, KR-1, Pentacam HR, IOLMaster 700, and Orbscan II were used. In evaluating CCT, MR-6000, Pentacam HR, and Orbscan II were included. WTW was measured by MR-6000, IOLMaster 700, and Orbscan II. The value of IOP was compared by MR-6000 and FT-1000. As statistical analysis for evaluating correlation and agreements between devices, repeated measures analysis of variance, Wilcoxon signed rank test, intraclass correlation coefficient (ICC), and Bland–Altman plot were used.

Thirty eyes of 30 patients were evaluated. Statistically significant differences in K_m between MR-6000, KR-1, Pentacam HR, and IOLMaster 700 were not observed (p > 0.05). Including Orbscan II, all five devices had almost perfect agreement in measuring keratometry (ICC > 0.80, p < 0.05). CCT measured by MR-6000 was significantly different from that of Pentacam HR and Orbscan II measurements (p < 0.05). Substantial correlation with that of Pentacam HR and Orbscan II measurements were observed(ICC > 0.60, p < 0.05). The WTW distance measured by MR-6000 was not significantly different from that measured by IOLMaster 700 with agreement but was different from that measured by Orbscan II. IOP measured by MR-6000 was not correlated with FT-1000.

MR-6000 has strengths in measuring different parameters at once on the spot. Therefore, we expected it to unify or substitute multiple preoperative examinations for cataract surgery. As a result, keratometric values obtained through MR-6000 can be interchangeably used with other devices based on good correlation and agreement. However, the CCT, WTW, and IOP values were not interchangeable with a single multifunctional unit for cataract surgery preoperative examination.