Statistical analysis The main outcome measures are rates of reading provided by the two reading tests, with the two tinted lens types, the overlay, and without any tint. These are quantitative tests and the results will be compared between the two groups using an unpaired t-test, and within individuals (between baseline and follow-up tests) using a repeated measures analysis of variance. In addition, qualitative data are obtained from participants' descriptions of their experience of reading difficulty at different stages of the study. These responses will be analysed using NVivo software to look for themes.