Landolt C charts are considered the gold standard of alternative eye charts since 1988. For testing at 4 Meters (13ft). Can be wall-mounted or utilized within the ETDRS Illuminator Cabinets. The chart was developed as an alternative to Snellen chart optotypes, which were not equally difficult. Each chart features only one carefully calibrated optotype placed in different positions (up, down, left, right, and 45 degree positions). The C used in the chart creates an equality throughout testing, giving the patient optimal opportunity. Patients must gesture or say which direction the C is facing, making testing simple and accurate.