How reading speed is affected by prism correction in exophoric patients

Abstract

Reading is a very crucial part of life. Good reading ability is necessary for daily tasks. People who have difficulty in reading (for any reason) can find it very frustrating throughout the day and can suffer from symptoms such as headaches, eye strain, etc. Reading speed is a factor that can indicate reading ability. Among many different factors that affect reading speed, one of the factors is the condition of exophoria. This is when the eyes tend to diverge and usually presents with difficulty to converge. When reading at a near distance the eyes must converge, making reading more difficult for people with exophoria. Measuring the eyes' deviation can be performed in different ways, giving different amounts of prisms needed to correct the exophoria and give more comfort. In this study, two methods are used (Fixation Disparity and Maddox Rod) to determine how many prisms would be necessary to prescribe and then test reading speed with each number of prisms. The results showed no significant difference in reading speed using each method to test for prisms, although subjectively it appears that there is a trend toward faster reading with prisms measured according to Fixation Disparity.