Is the ring scotoma of a monocular telescope present when viewing binocularly?

Telescope magnification causes a ring scotoma (blind area) around the magnified view, which has been suggested as a hazard when bioptic (spectacle-mounted) telescopes are used for driving. Preliminary work in our lab suggests when viewing binocularly on simple plain backgrounds, people can use the fellow (non-bioptic) eye to detect objects in the ring scotoma area (known as bi-ocular multiplexing). This paper presents preliminary findings on visually-complex noise backgrounds. To date 4 normally-sighted and 1 low vision subject have participated in pilot studies. Static perimetry was utilized to evaluate subject's bi-ocular multiplexing ability with and without the bioptic during passive and active fixation tasks. In general, detection performance of the fellow eye was similar without and with the bioptic, and was similar in the passive and active fixation conditions. These results suggest bi-ocular multiplexing is possible in visually-complex conditions and that the ring scotoma of a monocular bioptic is not always present in binocular viewing.