Figure 1.
Haploscope experimental setup which stimulates retinal disparity while keeping accommodation constant.
All visual stimuli were 40 cm away along midline for a constant 2.5D accommodative stimulus.
Figure 2.
Experimental Protocol (see text).
Figure 3.
Right eye movement responses decaying to the phoria position during the baseline recording (left plots A and C).
Adapted phoria responses are plotted on the right plots (plot B and D). Right eye movement responses decaying to the phoria position after 3 minutes of sustained fixation (long dashed line), after 30 seconds of sustained fixation during the near step phase (solid line) and after 30 seconds of sustained fixation during the far step phase (short dashed line) are shown in the right plots. The right eye movement response decaying to phoria is shown under two sustained fixation conditions, 16° or near adaptation (Plot B) and 1° or far adaptation (Plot D).
Figure 4.
Summary per subject of baseline phoria before 16° sustained fixation (dark gray bar), baseline phoria before 1° sustained fixation experiment (light gray bar), adapted phoria after 16° sustained fixation task (medium gray bar) and adapted phoria after 1° sustained fixation task (white bar) for all six subjects.
Adapted phoria measurements are the average of phoria measurements after the three minutes of sustained convergence, after near steps with an initial vergence position of 12° and after far steps with an initial vergence position of 1°. The error bars are one standard deviation from the mean.
Figure 5.
Typical ensemble convergence responses from a far initial vergence position of 1° (left) and from a near initial vergence position of 12° (right) after two sustained fixation conditions from subject S1.
Plots A and B are after the 1° sustained fixation task / far adaptation; plots C and D are after the 16° sustained fixation task / near adaptation. The subject fixated on a sustained fixation target for 3 minutes and then each step response was recorded after 30 seconds of sustained fixation.
Figure 6.
Typical ensemble convergence responses from a far initial vergence position of 1° (left) and from a near initial vergence position of 12° (right) after two sustained fixation conditions from subject S2.
Plots A and B are after the 1° sustained fixation task; plots C and D are after the 16° sustained fixation task. The subject fixated on a sustained fixation target for 3 minutes and then each step response was recorded after 30 seconds of sustained fixation.
Figure 7.
Summary of average peak velocities (°/s) with one standard deviation of all 4° convergence step responses after near 16° sustained fixation (top) and after far 1° sustained fixation (bottom).
Far step data after sustained fixation of 16° (black), near step data after sustained fixation of 16° (light gray), far step data after sustained fixation of 1° (dark gray) and near step data after sustained fixation of 1° (white) are plotted. The number of samples is reported below the plotted data. When the phoria is maintained at one position, convergence responses with a 1° initial vergence position are faster than responses with a 12° initial vergence position.
Figure 8.
Linear regression plot of the change in convergence peak velocity (°/s) of the near steps (solid triangle) and of the far steps (open circles) as a function of the change in phoria level (Δ).
The change in phoria level is defined as phoria after near [far] steps during the near sustained fixation task minus phoria after near [far] steps during the far sustained fixation task. Positive phoria changes refer to an esophoric shift in phoria. Similarly, the change in peak velocity is defined as the peak velocity of steps after the near sustained fixation task minus the peak velocity of steps after the far sustained task. Positive peak velocity changes refer to faster convergence peak velocity values during 16° (near) sustained fixation task compared to the 1° (far) sustained fixation task.