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Jason Shen, Frank Spors, Lance McNaughton, Chunming Liu; Refraction change after prolonged accommodation with different visual tasks. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6235.
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Hyperopic defocus, either on- or off-axis, has been hypothesized to be a stimulus for the development of refractive error. Prolonged accommodation has been identified as a risk associated with myopia progression, but it is still unclear if the accommodation stimulated by the various prolonged daily visual tasks is in the comparable ammount. The purpose of our study was to observe the refraction change after prolonged accommodation with different visual tasks.
A commercial Shack-Hartmann wavefront aberrometer was used to take measurements. Thirty subjects were recruited in the study and they were instructed to work on different visual tasks (read on computer, game on smartphone, watch movie on computer and read on paper, all at a distance of 50 cm) for 30 minutes. The measurements of central and peripheral refraction (30 degrees temporal visual field of right eye) were taken at start, 15 minutes and 30 minutes.
Slightly increased accommodation (0.08 ± 0.013 D) was observed when subjects were given reading tasks printed on paper from 15 minutes to 30 minutes. All the other three visual tasks, displayed either on computer monitor or smart phone screen, leaded a decreased accommodation over the measurements time frame (0.19 ± 0.063 D).
With prolonged near work, accommodation lag increased for visual tasks displayed on computer or smart phone screen. Increased accommodation lag indicated hyperopic shift of the retinal image and this shift of hyperopic defocus was symmetric across the visual field. The formed hyperopic image shell after prolonged accommodation is associated with further myopia progression.
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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