Abstract
Purpose: :
To evaluate spatial color contrast sensitivity (SCS) of different age groups and obtain normative data for clinical use.
Methods: :
Stationary chromatic sinusoidal grids (6.5° x 5º) with mean luminance of 15 cd/m² were generated along three chromatic axes (CIE 1931): red-blue, red-green and green-blue. Ishihara's Colour Plate Test and Moreland-Rayleigh Anomaloscopy were used to distinguish between normal trichromats and colorblinds. In the red-green axis, normal trichromats in three age groups were evaluated: 16-30 years (n = 50, age 21.5±2.8 years); 31-45 years (n =40, age 36.4±4.7 years), and 46-60 years (n = 31, age 51.1±4.4 years); 15 deutans and 5 protans were also evaluated. In the green-blue axis, normal trichromats in the same age groups (16-30 years: n = 43, age 21.1 ±2.5 years; 31-45 years: n = 30, age 37.5 ±4.5 years; 46-60 years: n = 30, age 51.7 ±4.7 years) as well as 14 deutans and 4 protans were also evaluated. In the red-blue axis, normal trichromats in the same age groups (16-30 years: n = 30, age 23.3 ±3.4 years; 31-45 years: n = 30, age 37.1 ±4.3 years; 46-60 years: n = 30, age 51.9 ±4.6), as well as 9 deutans and 3 protans were evaluated. Subjects were monocularly tested in four spatial frequencies (0.1, 0.2, 0.5 and 1.0 cycles per degree), with 9 different chromatic proportions and one luminance proportion. Statistical differences were assessed by means of an one-way ANOVA (p < 0.05), with Tukey's HSD used as post-hoc test whenever appropriate. The results show that color SCS shows a low pass characteristic in all tested groups.
Results: :
Color SCS decreased with age, mainly along the green-blue axis. For red-green SCS, the younger group had higher sensitivity than the other two groups at all spatial frequencies; the 31-45 years group had higher sensitivity than the 46-60 years group. For green-blue SCS, the younger group had higher sensitivity than the other two groups at all spatial frequencies; the 31-45 years group had SCS similar to the 46-60 years group. For red-blue SCS, the 16-30 years group had higher SCS than the 31-45 years group in 0.1 and 1.0 cpd, and higher SCS than the 46-60 years group at all spatial frequencies; there were no differences between the 31-45 years and 46-60 years groups. Colorblind subjects had color SCS lower than normal trichromats along the three axes and for all spatial frequencies.
Conclusions: :
Aging leads to a decrease in color SCS. Neural and optic factors may contribute to this phenomenon. Normative data for color SCS may be an useful tool to quantify visual losses in several visual dysfunction.
Keywords: color vision • pattern vision • contrast sensitivity