Abstract

Increasing letter magnification leads to increased reading rates for most visually impaired observers (Legge et al., 1985a). However in most cases, increasing magnification reduces the number of letters simultaneously visible (often called the field of view or window size). When reading horizontally scrolled magnified text, four to five letters were needed to attain maximal reading rates (Legge et al., 1985b). We have recently replicated this finding for this passive reading condition. Whittaker and Lovie-Kitchen (1993) have reported that the number of letters needed for self-navigated reading is substantially larger. However, Beckmann and Legge (1991; Beckmann et al., 1993) reported that for self-navigated reading with a CCTV, only 5 letters were needed to achieve maximal reading rates.

© 1996 Optical Society of America