Abstract
Abstract: :
Purpose:To compare measurements of retinal thickness in normal eyes using two different versions of two different techniques: the Retinal Thickness Analyzer (RTA, Talia Technology, Ltd, Mevaseret, Zion, Israel) version I vs version II, the Optical Coherence Tomography (OCT, Humphrey Instruments, Calif. USA) version II vs Stratus version and the RTA II vs Stratus OCT. Methods: For the RTA, 26 eyes from 16 healthy volunteers, 6 males and 10 females, aged from 40 to 64 years–old (mean: 54.0; SD: 5.74) were examined in the same session using the RTA I and the RTA II. For OCT, 54 eyes from 35 healthy volunteers, 11 males and 24 females, aged from 40 to 69 years–old (mean: 54.1; SD: 7.00) were examined in the same session using the OCT II and the Stratus OCT. In a third group of 30 eyes from 19 healthy volunteers, 6 males and 13 females, aged from 40 to 64 years–old (mean: 53.5; SD: 6.42), we compared the new versions, RTA II and Stratus OCT.Using special software, values of mean and SD were computed for areas of 600x600 microns in a total of 9 by 7 areas, for the RTA, while for OCT five values were computed, central disc of 1mm in diameter and 4 retinal quadrants (papillo–macular, superior, temporal and inferior) between 1 and 3 mm radii. For each of these five values, both the mean and SD were computed. Results:The RTA II presents increased values when compared with the RTA I, showing a statistical significant difference for the mean thickness. The values for the central area, are (mean (SD)) 136.7 (23.9) microns on the RTA I and 156.8 (19.2) for RTA II, respectively. For the OCT, the Stratus version presents higher retinal thickness values when compared to the OCT II. The central area presented values of (mean (SD)) 185.9 (16.21) and 202.3 (21.6), respectively for OCT II and Stratus OCT.Comparison between both new versions showed a ratio between Stratus OCT and RTA II retinal thickness measurements of 1.17 in the central disc of 1mm in diameter and 1.29 in the 4 retinal quadrants between 1 and 3 mm radii. Conclusions: The new versions of both instruments present higher values for retinal thickness. Also, both new versions present lower values for SD, except the Stratus OCT in the central 1 mm diameter area. The new versions of both instruments measure retinal thickness with increased reliability.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • imaging/image analysis: non–clinical