The invention is a system and method for measuring visual acuity. The system comprises a computer or projector adapted to project a computer generated image of an optotype on a surface, e.g. a computer display screen or a screen on a wall, and a control unit. The computer or projector is adapted to project the optotypes with a steadily changing size as a continuum of images. The testing is carried out by changing the optotype size in both directions in order to compensate for the reaction time of the patient. For example, starting with a large optotype, the size is steadily decreased until the patient signals that he can no longer read the optotype. The test then continues starting from a small optotype and steadily increasing the size until the patient signals that he can read the optotype.