Sight testing using optical patterns - has housing with mobile support bringing different patterns opposite window in turn

摘要

The patient sight-testing unit is particularly for checking visual acuity. It comprises a test housing containing a movable test support with a series of patterns forming the tests. These are brought in turn in line with a window in the housing. They can each have reference numbers, with an indication to the operator dependent on which test is visible through the window, typically a separate window in which the pattern number is shown. There can be a standard form for each pattern, to allow the operator to note the response of the patient to it.