The development of high magnification retinal imaging has brought with it the ability to track eye motion
with a precision of less than an arc minute. Previously these systems have provided only monocular
records. Here we describe a modification to the Tracking Scanning Laser Ophthalmoscope (Sheehy
et al., 2012) that splits the optical path in a way that slows the left and right retinas to be scanned almost
simultaneously by a single system. A mirror placed at a retinal conjugate point redirects half of each
horizontal scan line to the fellow eye. The collected video is a split image with left and right retinas
appearing side by side in each frame. Analysis of the retinal motion in the recorded video provides an
eye movement trace with very high temporal and spatial resolution.
Results are presented from scans of subjects with normal ocular motility that fixated steadily on a
green laser dot. The retinas were scanned at 4 eccentricity with a 2 square field. Eye position was
extracted offline from recorded videos with an FFT based image analysis program written in Matlab.
The noise level of the tracking was estimated to range from 0.25 to 0.5 arc min SD for three subjects.
In the binocular recordings, the left eye/right eye difference was 1–2 arc min SD for vertical motion
and 10–15 arc min SD for horizontal motion, in agreement with published values from other tracking
techniques.
2015 Elsevier Ltd. All ri