Validation of an Inexpensive Illuminant for Aeromedical Color Vision Screening

摘要

An inexpensive illuminant for color vision screening suggested by the NRC-NASCommittee on Vision was evaluated as a substitute for the Macbeth Easel Lamp. The Macbeth Easel Lamp is the recommended illuminant for pseudoisochromatic plate tests used in aeromedical color vision screening, but is no longer in production. Subjects included both normal trichromats (p=145) and persons with varying degrees and types of color vision deficiencies (p=152) as diagnosed with the Nagel Type I anomaloscope. Subjects were given the Dvorine Pseudo-Isochromatic Plate Test illuminated by each of the two light sources. One Verilux True Color Light tube (F15T8VLX) was installed in an adjustable fluorescent desk lamp and positioned at a height of 24 in above the center of the Dvorine test book to give a 270 lux illumination to match the illumination produced by the Macbeth light source. The two presentations of the Dvorine were separated by several other color vision tests. Each subject was given a different random order of plates 2-15 for each light source. Pass/Fail performance with the Dvorine test was virtually the same with the two light sources when criterion for failure was three or more errors. The Verilux True Color Light obtained a Kappa value of .97, and very low false positive (.021) and false negative (.006) rates when compared to the Macbeth Easel Lamp. Performance and possible applications of the Verilux True Color Light in aeromedical color vision screening are discussed.