To investigate the changes occurring in the axial length, choroidal thickness, and anterior biometrics of the eye during a 10-minute near task performed in downward gaze.
Twenty young adult subjects (10 emmetropes and 10 myopes) participated in this study. To measure ocular biometrics in downward gaze, an optical biometer was inclined on a custom-built height- and tilt-adjustable table. Baseline measures were collected after each subject performed a distance primary gaze control task for 10 minutes to provide washout period for previous visual tasks before each of three different accommodation/gaze conditions. These other three conditions included a near task (2.5 diopters [D]) in primary gaze and a near (2.5 D) and a far (0 D) accommodative task in downward gaze (25 degrees), all for 10 minutes’ duration. Immediately after and then 5 and 10 minutes from the commencement of each trial, measurements of ocular biometrics (e.g., anterior biometrics, axial length, choroidal thickness, and retinal thickness) were obtained.