[Setting the preferential retinal locus. Part 1. Analysis of the rehabilitation results as a function of positioning]

The aim of this study was to compare the various positions of preferred retinal locus (PRL) with the results of low vision rehabilitation to reading in view to elucidate the mechanisms involved.

We studied 100 visually impaired subjects who came to the center for rehabilitation of low vision. The technique is based on a scanning laser ophthalmoscope recording, compared with angiofluorographic pictures to obtain the PRL position with respect to the fovea.

It is shown that unsuccessful rehabilitations are not related to the eccentricity or to the angular value of the PRL but are only correlated to its absence. The difficulties that arise from the multiplicity of the PRL or from the confinement of the fovea by an annular scotoma can be overcome with the help of rehabilitation.

The upper and right positions are manifestly dominant, but they do not favor reading or writing. We believe that their purpose is to favor the integration of the new visual message of visually impaired people to facilitate their daily life activities. Therefore, using one or another of these peexisting PRL during eccentric viewing training should be preferred.