Six congenital CVD subjects were recruited. After colour vision screening using Ishihara plate, the Farnsworth-Munsell 100 Hue test was carried out to determine the type and severity of colour vision deficiency. Four types of red-tinted CL (Type A, B, C and D) were used. The performance of each of these lenses was determined through the comparison of error scores in the Ishihara test before and after wearing tinted contact lens on only the non-dominant eye. Then, the transmittance of each tinted CL was determined using a spectrophotometer. All these lenses were fitted on the subjects in one day where the subjects were given a 30-minute break for each intervention.
This study aimed to relate and compare the performance of 4 types of red-tinted contact lenses (CL) with the Total Error Score (TES) from the Farnsworth-Munsell 100 Hue test on colour deficient subjects. Only 6 subject with colour vision defect was tested in this study.