The Preferred Retinal Locus for Reading in Central Vision Loss.

Purpose: People with central vision loss (CVL) often adopt a preferred retinal locus (PRL) for fixation outside the region of central loss. However, it is unknown how often the fixational PRL (fPRL) is used in reading. Here, we assessed if the reading PRL is in the same location as the fPRL. Methods: Participants read text on a computer screen. Reading was randomly interrupted by blanking the screen, and participants reported the word being read when the blanking occurred. The location of this word was compared to the fPRL location, measured with an eye tracker. If reading uses the fPRL, the two locations should overlap. We validated our method with 10 normally sighted controls for whom the fPRL and reading PRL should coincide at the fovea. We then tested 20 participants with CVL. Results: Control participants reported the word at the fPRL, or the next word, in 77.03% of trials. Participants with CVL reported the word at the fPRL, or the next word, on 70.45% of trials. Seventeen reported the word at the fPRL most frequently. Two reported the word to the right of the PRL most frequently, possibly due to a look-ahead strategy. One reported the word to the left of the fPRL most frequently, the target of many regressive saccades. Only one participant with CVL used a reading PRL remote from the fPRL, consistently reporting the word 2 degrees below the fPRL. Conclusions: Most of the participants with CVL in our sample used a reading PRL in close proximity to their fixation PRL.