The ChromaGen contact lens system: colour vision test results and subjective responses

Abstract

The ChromaGen lens system is designed to enhance colour perception in colour vision deficiency (CVD). To investigate its efficacy, 14 CVD subjects were prescribed ChromaGen contact lenses. Colour vision tests (Ishihara, Farnsworth Munsell D-15, Farnsworth Lantern) were administered at baseline, lens dispensing, and after a 2-week lens-wearing trial during which subjective responses were recorded daily using visual analogue scales. ChromaGen lenses significantly reduced ishihara error rates (p < 0.001; ANOVA), particularly for deutan subjects. There was also a significant reduction in errors (p < 0.005) on the D-15 test. Conversely, lens wear had no significant effect on Farnsworth Lantern test performance. Subjectively, subjects reported enhanced colour perception, but poor vision in dim light. Judgement of distance and motion were only slightly affected. We conclude that ChromaGen lenses may enhance subjective colour experience and assist in certain colour-related tasks, but are not indicated as an aid for CVD in occupations with colour vision-related restrictions.

Subjects with colour vision deficiency in the community: what do primary care physicians need to know?

“…Currently, there is a paucity of primary studies to evaluate the costs and benefits of mass screening for acquired CVD, although some preliminary studies show that doing so may help detect diabetic retinopathy and primary open angle glaucoma earlier [8,58,[59][60][61][62].…”

“…Means of overcoming occupational colour deficiencies used include asking others, using instruments, keeping objects of different colours in separate places and avoiding colour tasks [4]. A 2001 study showed that the use of tinted contact lenses in CVD subjects significantly reduced error rates on the Ishihara and Farnsworth Munsell D-15 test [62]. This may provide some assistance in colour-related Data from Albany-Ward K [16].…”

Colour vision deficiency

“…64 Interestingly, the most recent small clinical trial of a new lens design found a statistically significant improvement in confusion index scores at the FM-D15 test: this finding cannot easily be explained by the introduction of luminance cues. 65 Any alteration to colour discrimination afforded by monocular tinted lenses is offset by alterations to depth and motion perception. Furthermore, it is clear that such filters do not 'normalise' colour vision.…”

Evaluation of the Waggoner Computerized Color Vision Test

“…Conventional cautions are still needed in its use, however. It would still be possible to cheat on the test perhaps by viewing it with a software application on a smartphone, using a colored filter, 18,19 or simply having another individual supply the answers during the test. Thus, the CCVT does not eliminate oversight by an examiner, although with the CCVT test, the examiner less likely needs to be a color vision specialist or even a health care provider.…”