Macular Metrics manufactures three versions of the instrument. The first version is intended for research and measures mutiple points on the retina. The second version is intended for clinical use and measures a single point in the center of the fovea.
The instrument uses selected light-emitting diodes (LEDs) to measure macular pigment, a yellowish substance in the eye that may protect the eye from the destructive effects of light. Professor Billy Wooten designed, built and tested the macular densitometer. The present instrument evolved over a period of many years of basic research.
A patient looks directly into the machine and adjusts a flickering light until it stops flickering, then repeats the process with a flickering light in peripheral vision. By comparing the two measurements, researchers can determine how much light is absorbed by the macular pigment and therefore how much macular pigment a patient has.
The underlying principal is called heterochromatic flicker photometry. For more information, see the section on flicker photometry in the Web Book titled The Joy of Visual Perception byPeter K. Kaiser.
Please address inquiries to Macular Metrics 12 River Street Rehoboth MA 02769