Abstract: A perimeter for perimetric eye testing is provided with an electronic control mechanism for varying the brightness of the light signals in a preselected manner such that reproducibility of the examination can be achieved. An optical indicating arrangement is included to indicate the brightness values to the examiner, while the electronic control mechanism can further control an electronic recorder for recording the results of the examination.

Abstract: An exchangeable device providing test patterns for eye examinations is provided to be insertable into an eye examination instrument, such as a projector or an eyepiece instrument. This device includes a cassette containing a rotatable disk carrying different test patterns with the test patterns being visible through light transparent portions of the cassette. The cassette is insertable into the instrument, and the test pattern is illuminated through the light transparent portions with the disk being rotated through coupling elements connected to a drive mechanism of the instrument to vary the test pattern.