Participants will be adults aged between 18 and 30 years, with symptoms of visual stress (discomfort when reading or experiencing perceptual symptoms when reading such as letters moving or distorted) or with a diagnosed reading difficulty (dyslexia). Participants will be recruited from the City University London optometry clinic and the City University London Learning Success unit. Participants within this age range and with visual stress will be eligible to participate. Potential participants with an ocular or systemic condition with possible impact on vision (e.g. amblyopia or diabetes respectively) or with intellectual disability will be excluded from the study. Each potential participant will undergo an eye examination prior to participation, during which the following tests will be conducted: