Abstract
Purpose :
To analyze the effect of stimuli characteristics: method, depth and field of view (FOV) on the accommodation response (AR) for emmetropes (EMM), late-onset myopes (LOM) and early-onset myopes (EOM).
Methods :
Monocular AR were measured under 60 different viewing conditions, the result of permuting the following factors: (1) stimulation procedure (free space, FS, or Badal lens viewing, BLV), (2) stimulus depth (flat or volumetric), (3) FOV (2.5°, 4°, 8°, 10°, 30°) and (4) amount of accommodation stimulation (AS: 0.17 D, 2.50 D, 5.00 D). The refractive error groups comprised n=9 EMM (those with a subjective spherical equivalent between 0.00 and +0.75 D), n=8 LOM those who became myopic after or at 15 years old) and n=9 EOM (before 15 years old).
Results :
Mixed ANOVA for the AS of 2.50 D showed a significant interaction between stimulus depth and FOV (F=2.73, p=0.03) and among stimulation methods, FOV and refractive groups (F=2.42, p=0.02). For the AS of 5.00 D, there was a significant effect of stimulation methods, stimulus depth and refractive groups (F=4.08, p=0.03). When controlling for the within factors interactions: LOM showed larger lags than EMM and EOM, and the most accurate AR was obtained for a FOV between 8° and 10°, which did not significantly differed for different stimulation methods or stimulus depth.
Conclusions :
AR were most accurate when the FOV was between 8° and 10°, which suggests that there may be an optimum peripheral retinal image size for accommodation stimulation. Previously reported differences in AR when using lens-based methods compared to FS viewing may be explained by the effect of other factors such as the FOV or the depth of the stimulus.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.