Short-term modification of vergence ramp eye movements in the convergent direction

Prior oculomotor studies have investigated the various effects of short-term modification on vergence, saccadic and smooth pursuit eye movements. Previous vergence studies have concentrated on step modification stimuli. Few have investigated the effects of modification on vergence ramp movements. Thus, this study explores the trends observed within a short-term modification experiment studying smoothly tracking vergence eye movements responses elicited from convergent ramp stimuli. A short-term modification experiment is composed of three phases: baseline, modification and recovery. Baseline and recovery phases contain only test stimuli; whereas, during modification, the subject is presented test and conditioning stimuli in a ratio of 1:5 test to conditioning. The test stimulus was a 0.5 deg/sec vergence ramp presented from a 3 deg vergence angle to a 5 deg vergence angle. The conditioning stimulus was a 2.0 deg/sec ramp presented over the same visual range. The root mean square error (RMSE) was calculated on all slower (0.5 deg/ sec) ramp responses and compared over the three phases. Preliminary data from one subject shows a trend where the RMSE increases within the recovery phase compared to responses recorded from the baseline phase.