Related Experiment Video
Updated: May 14, 2026
Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter
Published on: September 16, 2025
White-to-white corneal diameter differences in moderately and highly myopic eyes: partial coherence interferometry
Raul Martin1, Sara Ortiz, Ana Rio-Cristobal
1IOBA-Eye Institute, Department of Theoretical Physics, Atomic Physics and Optics, School of Optometry, University of Valladolid, Valladolid, Spain. raul@ioba.med.uva.es
Purpose:
To evaluate the differences between Orbscan scanning-slit topography and IOLMaster partial coherence interferometry (PCI) white-to-white (WTW) measurements in moderately and highly myopic eyes.
Setting:
IOBA-Eye Institute, University of Valladolid, Spain.
Design:
Comparative case series.
Methods:
Myopic eyes were divided according to the degree of myopia as follows: Group 1 (<6.00 diopters [D]), Group 2 (between 6.00 D and 12.00 D), and Group 3 (>12.00 D). The WTW distance was measured with the scanning-slit topography and PCI devices.
Results:
The study enrolled 328 eyes (64 subjects). The mean WTW in all eyes was 0.50 mm ± 0.26 (SD), lower with scanning-slit topography (11.69 ± 0.37 mm) than with PCI (12.19 ± 0.40 mm) (P<.01, paired t test). A low mean WTW was found in Group 2 (11.65 ± 0.34 and 12.15 ± 0.36 mm, scanning-slit topography and PCI, respectively) and Group 3 (11.51 ± 0.36 and 12.05 ± 0.46 mm, respectively) compared with Group 1 (11.79 ± 0.38 and 12.26 ± 0.40 mm, respectively) (P<.03, analysis of variance with Games-Howell correction). There was a low statistically significant relationship between WTW and spherical equivalent (SE) with both devices.
Conclusions:
Eyes with moderate and high degrees of myopia had lower WTW diameters than eyes with low spherical equivalent myopia measured with both devices. Scanning-slit topography provided less WTW distance than PCI in myopic eyes; thus, the devices are not clinically interchangeable.
