Abstract

In an eye with a central scotoma, the development and use for foveal visual tasks of one or more preferred retinal loci naturally and reliably occurs (Cummings, Whittaker et al., 1985; Timberlake, Mainster et al., 1986; Timberlake, Peli et al., 1987; Whittaker, Budd et al., 1988; White and Bedell, 1990; Schuchard and Raasch, 1992; Fletcher, Schuchard et al., 1993; Schuchard, 1993; Schuchard, 1994). The term preferred retinal locus (PRL) is reserved for those individuals who have chosen a preferred retinal area to act as a pseudofovea for foveal visual tasks (e.g., fixation and reading) due to a macular scotoma affecting visual performance. Previous studies have shown that 40% of low vision patients have central scotomas and thus probably have developed an eccentric PRL (Schuchard, 1993). These previous investigations of preferred retinal locus have studied each monocular PRL separately but individuals typically perform activities of daily living with both eyes open. Therefore the research laboratory investigations of preferred retinal loci (PRLs), to date, have forced individuals to perform visual tasks monocularly without fully understanding the consequences for the monocular PRL data collected.

© 1995 Optical Society of America