Optical measurement of human retinal macular pigment and its spatial distribution with age.

The existence of macular pigment (MP) in human eyes has been found to be of importance in the prevention of age-related macular degeneration (ARMD). A noninvasive technique of two-wavelength imaging fundus reflectometry was developed to measure the density distribution of this yellow pigment in retina in vivo. A total of 55 healthy human subjects were recruited and divided into three groups with average ages and sample sizes of 25.2+/-2.1 (N = 25), 40.2+/-8.3 (N = 13), and 67.5+/-7.1 years (N = 17), respectively. Only the MP distributions in the horizontal meridian of retinas are presented in this report. The results show that the average peak optical density of MP are 0.23+/-0.07, 0.21+/-0.05, and 0.25+/-0.06 from young to old groups, respectively. No significant difference is shown in the statistical t-test between the groups of the peak MP density. The half width of MP spatial distribution (HWMPD) are 4.8 degrees+/-1.5 degrees, 5.1 degrees+/-2.1 degrees and 7.7 degrees+/-2.0 degrees (1 degree = approximately 0.3 mm) from young to old groups, respectively. Mean HWMPD = approximately 5.6 degrees +/- 2.1 degrees. It shows that the area of MP is increased approximately by a rate of 0.06 degrees/yr according to the application of linear regression. However, the cause of the MP extension in the retina with age is unknown.