Fig 1.
Illustration of the type of defocus imposed on the right eye for each measurement day.
On six separate measurement days, the right eye was exposed to one of the following conditions (in a randomized order): (A) continuous hyperopic (-3 D) defocus (1 x 60 minutes), (B) continuous myopic (+3 D) defocus (1 x 60 minutes), (C) alternating low frequency cycles of hyperopic then myopic defocus (2 x 30 minutes), (D) alternating low frequency cycles of myopic then hyperopic defocus (2 x 30 minutes), (E) alternating high frequency cycles of hyperopic then myopic defocus (4 x 15 minutes), and (F) alternating high frequency cycles of myopic then hyperopic defocus (4 x 15 minutes).
Fig 2.
Schematic representation of the experimental set-up for axial length measures.
A binocular periscope system was used to allow fixation of the distant target (Maltese cross) while the Lenstar biometer measured axial length.
Fig 3.
The mean change in axial length from baseline (0 minute time point), during 60 minutes of continuous hyperopic defocus (Condition A) and continuous myopic defocus (Condition B) for all subjects.
Vertical error bars represent the standard error of the mean difference in axial length, and horizontal error bars represent the standard error in measurement time. Asterisks indicate a significant mean difference from baseline axial length (p < 0.05).
Table 1.
Mean change in axial length from baseline across different measurement times for continuous and alternating defocus conditions in all subjects.
Fig 4.
The mean change in axial length from baseline (0 minute time point) during 30 minute alternating cycles of hyperopic then myopic defocus (Condition C), and myopic then hyperopic defocus (Condition D) for all subjects.
Vertical error bars represent the standard error of the mean difference in axial length, and horizontal error bars represent the standard error in measurement time. Asterisks indicate a significant mean difference from the baseline axial length (p < 0.05).
Fig 5.
The mean change in axial length from baseline (0 minute time point) during 15 minute alternating cycles of hyperopic then myopic defocus (Condition E), and myopic then hyperopic defocus (Condition F) for all subjects.
Vertical error bars represent the standard error of the mean difference in axial length, and horizontal error bars represent the standard error in measurement time. Asterisks indicate a significant mean difference from the baseline axial length (p < 0.05).
Table 2.
Mean change in subfoveal choroidal thickness from baseline across different defocus conditions in all subjects.