Abstract
A novel Bayesian adaptive method, qReading, was recently developed to measure the reading speed versus print size function. Using a Bayesian adaptive procedure that selects the stimulus to optimize the expected information gain in each trial, the method was highly efficient and precise in assessing normally-sighted people. Here we examined its efficiency and precision in patients with visual impairments. The reading functions of eight visually-impaired observers (age: 29 to 72 years; near visual acuity: 0.39 to 0.81 LogMAR; viewing distance: 20 to 33 cm) were measured binocularly. Each observer read 60 sentences presented with the Rapid Serial Visual Presentation method at various speeds (25ms to 3s per word) and print sizes (0.5° to 4.2°) determined by qReading. Area under the reading curve (AUC) was calculated to quantify the overall reading performance. The 68.2% half width of the credible interval (HWCI) of the posterior distribution of reading speed was used to gauge the precision. For all observers, the AUC varied rapidly in the first few trials and started to level off within 10 trials, and it took up to 12 trials for the average HWCI of reading speed across print sizes to drop to 0.05 log10 units and about 30 trials or less to reach 0.03 log10 units. With 50 trials, the HWCI was 0.02 log10 units, same as that of the normal periphery (Shepard et al., 2019; 2021). Although the average test time was 13 mins, comparable to that in the normal periphery (Shepard et al., 2019), fewer trials (e.g., 20 trials) may be adequate to obtain precise estimates of the reading function in these patients. The qReading demonstrated outstanding precision and efficiency in visually-impaired individuals. It might serve as a valuable tool in research and clinical assessment for low vision.