The repeatability of colorimetry is precise(ly) as expected

The purpose of the study was to assess the repeatability of clinical assessments with the Intuitive Colorimeter, a repeatability classified as “poor” in a previous study. Patients underwent assessments with the Intuitive Colorimeter in two studies. In each study, one published by Suttle et al1 and the other described herein, assessments were undertaken on two occasions. The studies differ in respect of the models of colorimeter used, the methods employed, the interval between examinations, and the masking of examiners. The repeatability was assessed using the methods currently used in clinical practice, which differ according to examiner. Both studies show a similar repeatability of the assessments. This repeatability is consistent with previous literature. We estimate the standard deviation of u’ and v’ coordinates each to be 0.020 and thereby obtain an estimate of the number of tinted trial lenses necessary when prescribing coloured filters. In patients with visual stress assessment with the Intuitive Colorimeter is repeatable. The minimum number of tints necessary for assessment is estimated to be 77.