In-the-Spectacle-Lens Telescopic Device for Low Vision

of an object together with the unmagnified image of the rest of the scene except for the ringscotoma (Fig. 2a). With a small FOV, a telescope that is misaligned with the eye’s optical axiscan present a magnified image of an object immediately above the view of the same objectthrough the carrier lens (Fig. 2b). This method of dealing with the ring scotoma of the bioptictelescope was termed ‘Simulvision’ and was described with the introduction of the bi-leveltelemicroscopic apparatus (BITA) micro Galilean bioptic telescope 35 . Simulvision is anexample of spatial multiplexing by shifting 6 .abFigure 2: A simulated view of a road sign viewed through a 3× telescope. a)The view through a conventional bioptic. The magnified image on the retinablocks the view of much of the intersection creating a ring scotoma (blindarea). b) The rectangular field-of-view through the in-the-lens telescope.The magnified image is shifted up blocking part of the view of the overheadpedestrian bridge but leaves the intersection in full view. Note the nonmagnifiedview of the road sign seen under the magnified view. The whiteline surrounding the magnified image is only added to make the illustrationclearer.6