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David Nguyen-Tri, Jocelyn Faubert, William H Seiple, Olga Overbury; Fixation stability as a function of preferred retinal locus eccentricity. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5173.
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© ARVO (1962-2015); The Authors (2016-present)
Damage to the central retina is associated with a number of issues that are related to fixation stability. Previous research has examined changes occurring in late AMD. The purpose of this study was to investigate the relationship between loss of central vision and fixation stability by expanding the range of fixation loci.
An Optos® Optical Coherence Tomography/Scanning Laser Ophthalmoscope (OCT/SLO) unit was used to collect the data. Raster scans were taken on each eye in order to precisely determine location of the anatomical fovea. The SLO capabilities of the unit were used to assess fixation stability. In this task, participants were instructed to maintain their gaze on the fixation target as steadily as possible during recording.
Fixation data were fitted with a bivariate normal ellipse (BNE) encompassing 95% of data points. Bivariate Contour Ellipse Area (BCEA) was taken as a measure of fixation stability. Eccentricity was measured as the distance between the center of the fovea and the center of the BNE. To date, 65 eyes have been tested and analyzed for preferred retinal locus eccentricity and BCEA. Preliminary analyses have found a significant correlation between PRL eccentricity and fixation stability (R = 0.631, p < 0.001). Slope analysis indicates that BCEA increases by a factor of 1.6 per degree of PRL eccentricity. Further analyses will be conducted to assess other potential predictors of fixation stability.
As would be expected, there is a statistically significant link between preferred retinal locus eccentricity and fixation instability. However, proper foveation is not necessarily associated with stable fixation when the retina is damaged. This underscores the importance of training low-vision patients to use of an appropriate PRL.Acknowledgement: This study is supported through a partnership among the Antoine-Turmel Foundation, the FRQS, and the RRSV.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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