Subject matter under suclass 237 wherein written material or other target-subject matter us projected onto a screen or shown on a panel for controlled short periods of time to test the reading ability or visual acuity of an individual's eyes.
(1) Note. Class 434, particularly subclasses 159+, 167+, 185 and 327+ in some respects are similar to this subclass, these subclasses containing targets or reading charts and viewing devices. In this Class 351 the devices are directed as their primary purpose to testing the acuity of vision of an individual with short, accurate and selective timing, while in Class 434 the devices are dierected to the general purpose of testing knowledge or instructing in characteristics of article.
