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Y. Niu, F. Lu, B.–C. Jiang; The Difference in Accommodative Response Slope Between Emmetropic, Stable Myopic and Progressing Myopic Group . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3678.
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© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study was to investigate the difference in accommodative response slope (ARS) between emmetropic (Emm), stable myopic (SM), and progressing myopic (PM) subjects, whether the slopes before and after a period of near visual task were different and how different accommodative stimulus (AS) methods affect the ARS
Nineteen (Emm), 19 (SM), and 17 (PM) college students participated in this study. Myopes were fully corrected by soft contact lenses. A Maltese cross, which extended 110 in the visual angle in all testing distances (1, 2, 3, and 4 D), served as a stimulus target. The AS was changed by moving the display in real space or inserting minus lenses in front of the subject’s eye when the target was at 4 m. The subject’s accommodative responses (AR) were measured with a SEIKO WV 500 infrared auto–refractor before and after a near task. In the near task, the subject was asked to play a computer game at 40 cm for 30 min. The subject’s AR data were plotted vs. AS and a regression line was applied to obtain the ARS.
With the sequence of pre–near task and minus lens method, pre–near task and real space method, post–near task and minus lens method, and post–near task and real space method, average slopes for Emm were 0.886 ± 0.072 (S.D.), 0.813 ± 0.093, 0.852 ± 0.051, 0.763 ± 0.094; for SM were 0.875 ± 0.081, 0.822 ± 0.088, 0.834 ± 0.106, 0.786 ± 0.100, and for PM were 0.813 ± 0.122, 0.751 ± 0.076, 0.773 ± 0.132, 0.723 ± 0.087, respectively. The difference in ARS between the groups was significant (F[52, 2] = 5.03, p = 0.01). In all four conditions, the slopes of PM were different from the slopes of Emm and SM, except the difference between Emm and PM in the condition of post–near task and real space was not significant. The differences between the stimulus methods were significant in both pre– and post– near task conditions for all three groups. The difference in ARS between pre– and post– near task conditions was only significant in the Emm group.
This study confirmed the differences in ARS between Emm, SM, and PM, and showed that the stimulus methods used affected the ARS results. However, the near task only affected the ARS for Emm, but not for SM and PM.
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