Abstract
Purpose :
Spaide made scale drawings of the outer retina based on histological findings. It is possible to compare the drawings with OCT images using a longitudinal reflectivity profile (LRP) analysis. In the comparison, band 2 was aligned with the ellipsoid of the model. In contrast, the LRP of the IS/OS boundary reached a trough. But the comparison was made by using standard resolution SD-OCT. An ultrahigh resolution (UHR) SD-OCT can provide additional information to that provided by standard-resolution SD-OCT. We compared the thickness of the ellipsoid zone (EZ) obtained by a prototype UHR-SD-OCT with that obtained by a standard-resolution SD-OCT.
Methods :
Twenty-six eyes of 26 healthy volunteers were studied. B-scan images through the fovea were obtained by the two different OCT machines. We created LRP from the B-scan images. We majored the width of EZ at the 75% of the maximum reflectiveness at five points; a position of central fovea, a 0.5mm and 1.0mm temporal position from central fovea, a 0.5mm and 1.0mm nasal position from central fovea. And we compared the outer retina drawings with the UHR-SD-OCT images using the LRP analysis.
Results :
In the standard resolution SD-OCT, the full width at 75% of the maximum reflectiveness of EZ was 16.50±0.53 μm at the fovea, 16.65±0.45 μm at 0.5 mm temporal to the fovea, 15.90±0.47 μm at 0.5 mm nasal to the fovea, 16.80±0.35 μm at 1.0 mm temporal to the fovea, and 16.65±0.54 μm at 1.0 mm nasal to the fovea. In the UHR-SD-OCT, the full width at 75% of the maximum reflectiveness of the EZ was 7.30±0.60 μm at the fovea, 6.75±0.23 μm at 0.5 mm temporal to the fovea, 7.15±0.33 μm at 0.5 mm nasal to the fovea, 7.15±0.30 μm at 1.0 mm temporal to the fovea, and 6.40±0.37 μm at 1.0 mm nasal to the fovea. The full width at 75% of the maximum reflectiveness in the UHR-SD-OCT image was significantly thinner than that of the SD-OCT image at each of the five regions. In our comparisons, Band 2 was aligned with the distal ends of the ellipsoid section and/or the IS/OS boundary of the scale model.
Conclusions :
The macular EZ thickness in UHR-SD-OCT images was <45% of that in SD-OCT images. The band2 was aligned with the distal ends of the ellipsoid section and/or the IS/OS boundary of the scale model. While a drawing is not likely to be the final arbiter of band assignments, further studies are needs to determine the origin of band 2.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.