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Atanu Ghosh, Michael J Collins, Scott A Read, Brett A Davis; Spherical aberration of the eye during accommodation in downward gaze over time in emmetropes and myopes. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2060.
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© ARVO (1962-2015); The Authors (2016-present)
While a range of previous studies have investigated the changes in ocular aberrations during accommodation in primary gaze for a fixed pupil diameter at a single time point, there has been less attention on how the eye’s optics change over time with a sustained period of near work in downward gaze for natural pupils. Therefore, the current study investigated the changes in the optics of the eye during accommodation in downward gaze over 10-min duration.
Twenty six young adult subjects (14 myopes, 12 emmetropes) were recruited for this study. A Shack-Hartmann wavefront sensor was modified to measure the optics of the eye in downward gaze with different levels of accommodation. Baseline measures were obtained after subjects performed a control task (watching TV at 5 m distance in primary gaze) for 10 mins prior to each of three testing conditions. These three conditions included, distance accommodation in downward gaze, 2.5 D accommodation in downward gaze and 5 D accommodation in downward gaze. Measurements of ocular aberrations were taken immediately and then at 5 and 10 minutes from the commencement of each trial and Seidel longitudinal spherical aberration was derived.
Repeated measures analysis of variance revealed a significant influence of accommodation stimulus (p<0.001) on the changes in spherical aberration, and the longitudinal spherical aberration was significantly more negative in myopes (–1.08 ± 0.86 D) than emmetropes (–0.25 ± 0.73 D) after 10-min of the 5 D accommodation task (p<0.05). There was also a significant interaction between accommodation error (lag) and pupil size over time (p<0.001) and this interaction accounted for some of the changes in spherical aberration.
A change occurred over time in spherical aberration during the near task in downward gaze when measured with natural pupils. Myopes showed greater changes in the higher-order optics than emmetropes over 10-min when performing a near task in downward gaze. These findings provide a more realistic reflection of the eye’s natural optical properties during typical near tasks.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Dioptric values of group mean (±SD) longitudinal spherical aberration during distance and near accommodation in downward gaze over 10-min for natural pupil diameters among emmetropes and myopes. Asterisks indicate statistically significant difference between myopes and emmetropes (p<0.05).
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