The object of the Tritan Album is to facilitate the qualitative diagnosis and quantitative evaluation of blue-yellow dyschromatopsia. Such dyschromatopsia is very rarely hereditary and much more commonly acquired as a secondary to other problems of the eye and the optic pathways. Thus the Tritan Album is principally a test to be used in clinical ophthalmology.

105910   Lanthony Tritan Album .......... $251.00

Description

The Tritan Album consists of 6 Pseudoisochromatic plates numbered from 0 to 5. Each plate is in the form of a square and consists of a multiplicity of small circles in close juxtaposition. These small circles are so arranged as to form, on one hand, a gray background (very closely corresponding to Munsell chroma from 10 to 2), while the difficulty of reading the plates increases from plate No.1 to plate No.5.

Procedure

Each plate is presented in turn to the subject, and the examiner says "You will see one big square with a smaller square in one of it's corners; just tell me in which corner the smaller square is situated". The patient will reply either verbally (top, bottom, left, or right.) or by pointing, but must not be allowed to touch the plates. Only one answer is allowed.

The correct answers are as follows:

Scoring

The score is decided by the number of the last plate read. If plate No.0 was not read scoring is not possible. If only plate No.0 was read (i.e. plate No.1 was not) the score is 0/5. If plates No.0 and 1 are read (but not No.2) the score is 1/5, and so on until if all the plates are read, including No.5 the score is 5/5.

Significance

Plate No.0 is a demonstration  plate read by all normal subjects and also by hereditary color defectives. A subject's inability to read plate No.0 is therefore without value from the point of view of color discrimination, it is usually connected with a too poor visual acuity.

The inability of a subject to read one or more of the plates from No.1 to No.5 is characteristic of color -defective vision on the blue-yellow axis (tritanopic defect). Qualitatively the Tritan Album is specific to the blue-yellow axis, thus the red-green dichromats are not diagnosed by this album and should be evaluated with a different test (for example, the HRR). However , the association of these two types of color defect is possible and the presence of one type does not itself exclude the presence of the other. Quantitatively, the importance of the color defect is evaluated as a function of the number of plates not read, and from the score which is thus derived. Nevertheless, plate No.5 is by no means easy to read even by normal subjects, also the inability to read only this plate (score 4/5) ought to be checked by a different color test.

Precautions in use

The illumination should be at least 500 lux and having a color temperature of the order of 6000º K.

Incandescent lighting is therefore proscribed.

The plates must not be exposed to the direct light of the sun, and the Album should be kept closed when not in use. The plates should never be touched by the fingers.

Dr. P. Lanthony

Laboratories de la Vision des Coleurs

Centre National D'Ophtalmologie des Quinze-Vingts

28 Rue de Charenton - 75012 Paris

France

Appendix

Munsell Coordinates for the Tritan Album Plates

Hahn Chip Test

Daylight Illuminator

Color Vision Test Comparison Chart

Color Vision Test Index