Abstract
Abstract: :
Purpose: To built a device for measuring the optical density of macular pigment in the human eye. The apparatus should allow fast, objective measurements with the natural pupil. Methods: We designed an apparatus based on spectral analysis of white light reflected from the fovea. A small halogen lamp illuminates a 1 degree spot on the retina; the same area is analyzed. Entrance and exit pupils fit into a 3 mm diameter circle. Reflected light was analyzed with a commercial fiber spectrometer in the range 400 – 800 nm. Twenty healthy subjects, age 18–79 years, participated in the study. Measurements were repeated 5 times in conditions (1) natural pupil in dark room, (2) natural pupil with dim room light, and (3) dilated pupil in dark room. Another series of 5 measurement (dark room) was obtained in a subset of 10 subjects after an interval of at least three days. Data analysis with a model of reflectors and absorbers in the eye provided the density of the macular pigment. For comparison macular pigment was also measured with heterochromatic flicker photometry in dim room light and natural pupil. Results: Measurements were successfully completed in all subjects. With the Macular Pigment Reflectometer room light and pupil dilatation had no influence on measured density. Mean within subjects variation was typically 7 %. Mean difference between test and retest after at least three days was 1 %. Correlation between Macular Pigment Reflectometer and Heterochromatic flicker photometry was r = 0.64 (p<0.01). Mean within subjects variation with HFR was 19 %. Conclusions: We succeeded in building an instrument for a fast, reliable and comfortable measurement of MPOD in subjects with their natural pupil. The instrument holds great promises for epidemiological research.
Keywords: macular pigment