Effects Of Correcting Fixation Disparity On Digital Eye Strain

Abstract

Digital Eye Strain (DES) is a widespread and highly prevalent condition whose incidence appears to be rising during the present pandemic. It comprises a range of visual and ocular symptoms which occur after viewing a digital screen for an extended period of time. Previous work from our laboratory has shown the magnitude of fixation disparity to be the only clinical parameter that is significantly correlated with DES symptoms. Therefore, this study sought to determine whether correcting the underlying fixation disparity will significantly reduce DES symptoms. Thirty young, visually-normal students were required to read randomly generated words from a digital tablet device for 20 minutes. Three different trials were performed, with the subject wearing either: (i) the prism that corrected their fixation disparity, (ii) the same magnitude of prism as for condition (i) but with the opposite base direction or (iii) a near addition lens that corrected the fixation disparity. Immediately after the reading task, subjects rated their ocular and visual symptoms on a questionnaire. There was no significant difference between the mean symptom scores for the three conditions. However, this may be due, in part, to the small number of subjects encountered with large values of fixation disparity. Future studies should further examine the range of oculomotor responses associated with DES in order to provide appropriate treatment options.