Abstract
Purpose :
The Eye Surface Profilometer (ESP) allows measurements of corneal and scleral topography that have provided information about the characteristics of the in-vivo human anterior eye shape and have been used in contact lens fitting and design. This study aimed to examine the intersession and intrasession repeatability of sagittal height and corneal sphero-cylinder measurements from the ESP.
Methods :
Forty-five young healthy adult subjects (mean age 25 ± 5 years) with a range of refractive errors had two sessions of anterior eye surface shape measurements captured with the ESP, separated by 20 minutes. At each session, three consecutive scans were captured by a single operator. Sphero-cylinder data (M, J0, and J45) from the central cornea and sagittal height data from the central 8 mm of the cornea and the region from 8 to 14 mm of corneal periphery/anterior sclera on the nasal and temporal anterior eye surface were assessed to calculate the measurements’ intersession and intrasession co-efficient of repeatability (CR) using Bland-Altman analyses.
Results :
The intersession CRs of sagittal height measurements for the nasal (5 µm) and temporal (7 µm) central corneal regions were better than the peripheral nasal (24 µm) and temporal (21 µm) regions (all p < 0.001). The sagittal height within-subject standard deviations of the three repeated scans were 3, 3, 10, and 11 µm for central nasal, central temporal, peripheral nasal, and peripheral temporal region, respectively. Figure 1 shows the sagittal height Bland-Altman analysis of the central and peripheral nasal and temporal regions.
Intersession CRs of 0.67, 0.22, and 0.13 D and within-subject standard deviations of the three repeated scans of 0.46, 0.08, and 0.10 D were achieved for measurements of corneal power vectors M, J0, and J45, respectively.
Conclusions :
Central corneal sagittal height and sphero-cylinder measurements provided by the ESP are highly repeatable and comparable with other anterior eye topographers, however, sagittal height repeatability reduces towards the periphery. These outcomes should be considered in the clinical and research applications of anterior eye surface topography results from the ESP.
This is a 2021 ARVO Annual Meeting abstract.