Although adaptive optics (AO) provides the best possible
images in retinal scanners, scanning through the natural optics of
the eye can usually provide images of sufficient quality for tracking.
The Tracking Scanning Laser Ophthalmoscope (Sheehy et al.,
2012) or TSLO is a non-AO system that scans the retina over a 1–
5 field with sufficient contrast and resolution to see individual
cones over most of the retina. Real time image analysis associated
with the TSLO provides an on line estimate of horizontal and vertical
eye position with an accuracy of better than an arc minute,
and it produces analog output signals for use outside the TSLO. This
system has recently been combined with an OCT scanner to
improve the quality of volumetric images (Vienola et al., 2012).
Fixational eye movements recorded with retina scanners have
to date been limited to monocular eye movements. Here we
describe a modification to the TSLO that allows for recording of
both eyes simultaneously with a single scanner. Real time tracking
of the two eyes has not yet been implemented, so we report on
results from off line analysis of the videos that show eye motion
features comparable to the best high precision eye tracking systems.
Briefly, we split the optical path with a knife edge mirror
so that half the horizontal scan goes to one eye and half to the
other, resulting in a split field image containing simultaneous