In addition, demographic information relevant to our study will be collected in order to appropriately describe the population and explore if these factors modify the test-retest correlations. Variables such as age, sex, highest level of education achieved (i.e. secondary school, CEGEP, university), the use of corrective lenses for vision problems, occupation, and any relevant past medical history (i.e. migraines, vision problems, medication, etc) will be included.