Guest editorial: Notes on the macular pigment.

Potential functions of the macular pigment are reviewed. Its role as a protector of the retina in respect of the blue-light hazard, and its relation to the rods and the cones, are examined. It is tentatively suggested that its presence in the human retina originated in the wild as a result of diet and not as a special evolutionary process: the pigment does not appear to be able to offer any significant photic protection, and the effect on chromatic aberration, as recently reported, may be negligible. Its relation to the spectral placing of photopigments is also examined.