Abstract
Purpose :
Widefield and Ultra-widefield (UWF) terms are frequently used without a clear agreement on the definitions. The widefield imaging study group recently defined widefield as technology that in a single image capture includes at least four vortex vein ampullae and ultra-widefield as capturing the retina in all four quadrants beyond the vortex vein ampulla in a single capture. The purpose of this study was to evaluate two different widefield technologies with regards to detection of the numbers of fundus quadrants visible in real clinical practice.
Methods :
After IRB approval was obtained, patients within routine clinical practice were imaged with two devices, a confocal scanning laser ophthalmoscope (cSLO)(Optos P200DTx/California; Optos plc, Dunfermline, Fife, U.K.), and a broad line fundus imaging ophthalmoscope with both a single shot image and a montage image (BLFI)(Clarus 500; Carl Zeiss Magitec, Inc., CA,USA). The primary outcome was the number of quadrants visible in the fundus image defined as “visible” if a vortex ampullae was present. Two trained masked reviewers analyzed the green-free channel to accentuate the choroidal layer with a tertiary grader for resolution of discrepancies. The area within each of four visualized quadrants was calculated using ImageJ (Version 1.52a, NIH, Bethesda, MD) and compared between the 2 imaging modalities.
Results :
On average, the cSLO was found to image more vortex ampullae than BLFI single shot image or montage image. The cSLO imaged 116 of the possible 260 (45%), the BLFI single shot image 8 of 260 (3%), and BLFI montage imaged 96 of 260 quadrants (37%). Only 5 eyes from cSLO and no images from the BSLI single shot image met the ultra-widefield consensus definition. The superotemporal vortex ampullae was more visible when compared with the others quadrants. The average area per individual quadrant imaged by cSLO had a greater result in comparison with BLFI montage and BLFI single picture (Figure 1).
Conclusions :
In routine clinical practice, there was a low rate of achieving the UWF defined images using both systems. cSLO has been shown images greater number of vortex ampullae than BLFI camera both in single shot and montage image format. Furthermore, the cSLO covered a significantly larger retinal area in all quadrants.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.