Abstract: A method for using mass-produced light-emitting diodes of a predetermined luminance in instruments requiring a precise luminance value and a light-emitting diode arrangement for adapting such mass-produced light emitting diodes to such instruments. The above-noted method includes the steps of disposing an LED in a lengthwise adjustable manner within a sleeve, closing the sleeve with a light diffusing disc at an end thereof from which the light from the LED is intended to merge and displacing the LED within the sleeve in such a manner that a precisely defined luminance appears at the diffused disc. In accordance with a preferred embodiment of the apparatus, a tubular sleeve of an elastic plastic material is provided with mounting threads at one end thereof for mounting same within a cap with a light-diffusing disc located between the threaded end of the sleeve and the cap. Additionally, the sleeve is provided with longitudinally extending beads within which electrical connectors of the LED can be mounted.

Abstract: A perimetric eye examination device is provided having light-emitting diodes for the respective light sources which are perceived during the eye examinations. These light-emitting diodes are controllable for their brightness, either in linear dependence on the current, or in linear dependence on the pulse width repetition ratio of current pulses supplied to the light-emitting diode. The brightness perceived from the respective light-emitting diodes on the surface of the perimetric eye examination device also may be varied in accordance with physiological characteristics of the eye wherein the light-emitting diodes are distributed on the surface of the device with the brightness increasing from the central area of the observation area toward the periphery of the observation area.