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Petros Papadogiannis, Dmitry Romashchenko, Peter Unsbo, Linda Lundström; Influence of optical defocus on peripheral vision with and without aberrations. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5808.
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© ARVO (1962-2015); The Authors (2016-present)
Myopia development is related to the sign of the relative peripheral refraction. It is therefore interesting that many myopes show asymmetries in their sensitivity to defocus. Compared to nonmyopes, nearsighted individuals tend to see better with hypermetropic (negative) defocus foveally as well as in the periphery. This study aims to determine the role of chromatic aberrations (CA) and higher order monochromatic aberrations (HOA) in this asymmetry by investigating how peripheral vision is affected by the sign of defocus with and without aberrations present.
Peripheral resolution threshold was evaluated in 20o nasal visual field of the right eye of a myopic subject in 10 % contrast with stationary gratings (leaning to the left or right in a 2 alternative-forced-choice paradigm) with induced defocus between ±5 D in three conditions: 1) Best sphere and cylinder(BSC) correction, 2) BSC correction + CA elimination and 3) BSC correction + CA elimination + HOA correction. Trial lenses were used for the BSC correction, a narrow band pass filter (550nm; bandwidth 25nm; given an average luminance over 20 cd/m2) was used to eliminate CA (green light conditions) and an adaptive optics system running in a continuous closed loop was used for HOA correction. No cycloplegia was used, and defocus was measured live during the vision evaluation by a Hartmann-Shack wavefront sensor, thus any changes in accommodation were taken into consideration during the data analysis. The spectacle magnification of the trial lenses was compensated for, and all measurements were repeated 3 times.
Peripheral resolution varied with defocus similarly for white and green light when the natural HOA were present. The average slopes for white and green light were 0.08 and 0.07 logMAR/D for negative defocus and 0.15 and 0.14 logMAR/D for positive defocus, respectively (yellow and green data in the graph). With adaptive optics correction for HOA, the average slopes for green light were 0.17 and 0.16 logMAR/D for negative and positive defocus, respectively (blue data in graph).
Judging from the slopes, there was no effect on the asymmetry after CA elimination in this subject. However, with adaptive optics correction for HOA, the myopic subject showed a symmetric reduction in vision under positive and negative defocus.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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