Purpose:
Given the increased temporal sensitivity of the peripheral visual field and the increased Troxler effect at peripheral eccentricities, we examined whether "jittering" text on a computer monitor increases acuity and decreases reaction times for character identification.
Methods:
Three normally sighted subjects were tested monocularly, with the non-tested eye patched. Letter stimuli were presented at an eccentricity of ten degrees in the temporal retina. Four "jitter" settings were tested: no jitter, frequency of 5 Hz with an amplitude of 2 pixels, frequency of 10 Hz with an amplitude of 5 pixels, and a frequency of 15 Hz with an amplitude of 10 pixels. In separate trials, 10 letters of each size (over a range from 20/50 to 20/170 equivalent Snellen) were presented. The computer program randomly generated a letter and the subject was required to identify the stimulus as quickly as possible. The accuracy and time required to identify each letter were recorded.
Results:
Two of the three subjects showed improvements in identification accuracy when the letters were "jittered" as compared to stationary letters, as expressed in the table. These improvements in accuracy were positively correlated with the frequency and the amplitude of jitter. Similar improvements were observed in all letter sizes.
Conclusions:
Reading using the peripheral retina appears to be improved by jittering the text. Future development of a program that jitters text may serve as a useful reading aid for patients with partially impaired maculas, such as those with age-related macular degeneration (AMD). Expansion of this protocol to include subjects with AMD is currently underway.
Keywords: temporal vision • age-related macular degeneration • adaptation: motion