SIMULATION OF TRITAN DEFICIENCIES FOR THE EVALUATION OF CLINICAL COLOUR VISION TESTS

Title SIMULATION OF TRITAN DEFICIENCIES FOR THE EVALUATION OF CLINICAL COLOUR VISION TESTS
Author, Co-Author Stephen Dain, Ph.D. F.A.A.O.
Topic
Year
1992
Day
Sunday
Program Number
3:00 pm
Room
Ireland B
Affiliation
Abstract The three means of artificially inducing a blue-yellow colour vision deficiency are well known. These comprise making the stimuli sufficiently small (small field tritanopia), reducing the illuminance on the task (mesopization) and by limiting the duration of the stimulus. A blue-yellow deficiency induced by any of these methods could be used for the assessment of clinical colour vision tests. For brevity and simplicity one of the methods should be adopted. The three induced colour vision deficiencies were assessed using The City University Test (Second edition) and the SPP plates (Volume 2) as both tests examine red-green and blue-yellow discrimination and their construction is conducive to the brief presentation and remote viewing necessary. All test plates were presented in a pseudo-random order and (for the TCU test) random orientation starting at the most difficult condition (darkest, briefest or smallest). For the reduced illumination experiment the subject viewed the test through neutral density filters giving an effective illuminance of 2 lux. Filters were reduced until the level at which all plates could be identified correctly. The viewing time was reduced to 4 ms and increased to the point at which all responses were correct. For the size task, the subject approached the test plate until the correct responses were elicited. The specificity of the blue-yellow deficiency induced was used as the criterion for the most successful simulation. The order (decreasing) of specificity in the simulation was small stimulus then duration then low luminance. This method of assessment can successfully be used for assessing clinical colour vision tests.
Affiliation of Co-Authors
Outline