Technical basis

The Hess-Screen from Meditron is a metal plate, 95 cm wide and 95 cm high, to which the Hess co-ordinates have been applied by means of a screen printing process. The co-ordinate lines are dotted at a dot pitch of 0.5°, which improves accuracy of reading. The fixed points are displayed by a laser light in a complementary colour. They are marked in the 9 main directions of gaze at 15° and 30° from the primary position of gaze by means of a special plastic material. Because this has the property of lighting up in laser light, there is no need for an expensive electronic drive of light diodes.