Used to evaluate the alignment of the eyes and their movements both individually and in tandem. Provides measure of horizontal, vertical and cyclodeviation simultaneously for pediatric and adult patients.

The test is conducted in low light at one meter. The patient is positioned with chin on the chin rest and wears red/green Anaglyph glasses to insure separation of each eye. The patient uses one line generating laser and the examiner uses the other laser. The patient is then asked to superimpose one image upon the projected image from the examiner. Any difference or deviation indicates the deviation direction and magnitude of the measured eye from the normal axis. By swapping the lasers, between the patient and examiner, the other eye may be examined.

The Lancaster Screen measures 60" square (150cm x150 cm) and is mounted on roller for convenient storage. The red grid is not visible to patient to avoid ocular clues. Score sheets are a replica of the grid on the screen. The Heavy Duty Chin Rest is available to avoid head movement during the test. The Hess Lasers are also available and project a single dot of each color. The Hess Lasers can be used with the Lancaster Screen. The Paraboloic Hess Screen is not yet available.