Evaluating Barten image metric for predicting character recognition in people with low vision.

Electronic devices with small visual displays (SVDs) are often inaccessible to the millions of Americans with vision loss. The Barten square root integral (SQRI) is an image quality metric that has been shown to predict whether people with normal vision can see images on a cathode ray tube monitor. The present proof-of-concept study begins to explore whether the same metric could predict the ability of users with low vision to see images on SVDs. In a sample population of 33 adults with low vision, the Barten SQRI was the best predictor of the ability to recognize low-contrast single digits on a screen (r(2) = 0.80, p < 0.01), followed by the Pelli-Robson Contrast Sensitivity Chart (r(2) = 0.69, p < 0.01). Visual acuity was not significantly predictive of the ability to read low-contrast characters on a display. Further work will explore whether the Barten SQRI remains predictive of the ability of people with low vision to use actual devices that have SVDs.