Colour Vision

Colour vision needs to be regularly examined in many occupations. Screening uses Ishihara-type pseudoisochromatic tests that are very sensitive and may give positive result even if the person has normal colour vision. Therefore each positive result needs to be tested further, assessed, by using sorting tests like Farnsworth Panel D-15 or LEA Test Panel 16 or anomaloscope.

The Panel 16 test can be used in assesment of both normally sighted and visually impaired workers. The large color area of the test caps is suitable in assessment of ability to see colour differences when the objects are larger and the small test area through the centre of the restriction ring depicts colour perception in the fixation area. In occupational health and school health examinations a single set of test caps is used.