Abstract
Purpose :
While stable eye fixation during visual field (VF) test is one of important factors to obtain reliable results in clinical practice, fixation eye movements occur even though subjects are trying to control their gaze on the fixation target. The fixation eye movements during VF test in a clinical setting has not been well known. The purpose of this study was to measure the fixation eye movements during a stimulus target presenting (200ms) in the middle of VF test using head-mounted perimeter “imo”.
Methods :
Subjects were seven healthy volunteers who underwent a customized VF test program for right eye with the imo 10 times, stimulus intensity: 20dB, stimulus size: ΙΙΙ, stimulus presentation duration: 200msec, test time: about 17sec, 10 test locations: (±3,-3), (±9,-3), (±15,-3), (±21,-3), (±27,-3). Eye positions were monitored with a CMOS sensor camera (300fps, 640×508 pixels) built-in the imo perimeter (Matsumoto C, et al. PLos One. 2016). Fixation eye movements during stimulus presentation (200msec) were calculated to measure changes of vertical and horizontal eye positions. The bivariate contour ellipse area (BCEA) was used to evaluate the area of fixation eye movements.
Results :
Average BCEA of all test locations during entire VF test and stimulus presentation (200msec) were 0.695 deg2 (SD=0.266, maximum=1.293, minimum=0.291) and 0.016 deg2 (SD=0.01, maximum=0.051, minimum=0.003). There were no significant differences of BCEAs among ten test locations (p=0.83).
Conclusions :
imo was able to measure fixation eye movements. The area of fixation eye movements during stimulus presentation was about one third of the size ΙΙΙ stimulus target (0.146 deg2), our results suggest that the size ΙΙΙ stimulates larger area of retinal ganglion cells than 0.146 deg2.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.