Study designs of evaluations included in the review
Meta-analyses, randomised controlled trials (RCTs), cohort studies, case-control studies, before and after studies and descriptive studies were eligible for inclusion in the review. Economic analyses were also considered.
The following criteria were used to exclude studies from appraisal: participation rate <50%, sample size < 25, updated results published, papers for debate or editorials, abstract only.
Specific interventions included in the review
Studies examining the validity of colour vision screening tests or colour vision screening programmes were eligible for inclusion in the review.
Specific screening tests used in included studies were: Pease-Allen colour test (PACT), Ishihara, Ishihara unlettered, Ishihara (pathway), American Optical Hardy-Rand-Rittler (AO-HRR), Panel D-15, F-2, Kojima-Matsubara test plates, Anomaloscopy, the Anomoloscope Plate Test (APT-5), Velhagen Pflugertrident Test, Hahn pseudoisochromatic test, standard pseudoisochromatic test, pseudoisochromatic plates (new design), Farnsworth-Munsell D-15, Farnsworth Lantern, Farnsworth F-2, Guys, Matsubara, Ishihara and AO-HRR plates versus slides, Panel D-15 desaturated, F-M (10) 100-hue, F-M 100-hue test versus colour screening inventory, and the Lanthony Tritan Album.
In one study that examined options for the treatment of colour vision deficiencies, long wavelength pass filters were used as a treatment.
Reference standard test against which the new test was compared
No inclusion criteria relating to any reference standard test were specified. Rererence standard tests used in included studies, where specified, were anomaloscopy or AO-HRR.
Participants included in the review
Participant inclusion criteria were not provided. Studies were excluded if there were significant differences in the baseline characteristics of their case and control groups, or if there was a lack of reported demographic details of the study participants.
For studies investigating the sensitivity and specificity of colour vision tests, the age of participants ranged from 4 to 63 years. The samples included: "the adult population", colour normal adults, adults with red-green colour deficiency, children, students, and vision impaired participants (who had been referred to an optometry colour vision clinic).
The mean age of participants involved in the sensitivity of colour vision screening tests ranged from 19.9 to 28. Participants included: red-green colour deficient males, people with congenital colour vision impairment, people with impaired colour vision (diagnosed by anomaloscopy), and volunteers.
In studies evaluating the validity of colour vision screening tests with "other" outcome measures, participants were age 3-74. Participants included patients with congenital red-green colour blindness, patients with optic neuritis, and controls with no colour impairment.
The single study investigating the repeatability of the Ishihara test involved colour vision impaired participants between 17 and 35 years of age.
In studies evaluating how children perform on colour vision testing, children were aged 2 to 13 years.
In four studies evaluating screening programmes that stated participant age, it ranged from 8 to 16 years.
Outcomes assessed in the review
No inclusion criteria were specified with respect to outcome measures.
The following outcomes were assessed in the review: sensitivity, specificity, repeatability, acceptability, positive predictive value and negative predictive value.
How were decisions on the relevance of primary studies made?
A single reviewer applied the inclusion criteria.