[Evaluation of the desaturated Panel D-15. IV. Effect of the repetition of desaturated Panel D-15]

The desaturated Panel D-15 was performed in a repetitive manner to determine whether such repetition improves test results, and, specially, whether repetition can eliminate false positives.

The study population included 100 subjects with normal colour vision. The experimental procedure included: first the standard Farnsworth's Panel D-15 test, then the desaturated Panel D-15 test performed three times consecutively by each subject. Qualitative evaluation with the Farnsworth D-15 classical diagram and quantitative evaluation with scores calibrated according to the ages of the subjects were used.

The standard Panel D-15, performed first, was of no predictive value for the subsequent desaturated Panel D-15 (Cohen's K = 0.08). The desaturated Panel D-15 performed three times consecutively gave evidence of improvement in all the studied variables, from the first to the third time: scores tended toward low values, lower mean score (from 85 to 42); more zero scores (from 17 to 32); smaller number of abnormal scores (from 16 to 3). At the first performance of the desaturated Panel D-15, there were 16% false positives. At the second, there were 3%; and at the third, none of the initial false positives occurred.

Three successive performances of the desaturated Panel D-15 were necessary and sufficient to eliminate all false positives and can also assess some abnormal results.