A role for the macular carotenoids in visual motor response

Abstract

Objectives

Lutein (L), zeaxanthin (Z), and meso-zeaxanthin are the dominant carotenoids within the central retina (there, termed macular pigment, MP). L is also the dominant carotenoid in the brain. The presence of L and Z in both motor and visual areas of the central nervous system is consistent with a role of these carotenoids in visual–motor behavior. The purpose of this study was to provide a first test of this hypothesis.

Methods

Balance ability (measured via the Standing Leg Test) and simple reaction time (measured via a stimulus appearing in one of four quadrants of a computer monitor) were measured in 49 subjects (mean age = 54.8 years). Fixed and variable reaction time, and coincidence anticipation ability (estimating the arrival of the stimulus at a target location moving at four velocities) were assessed in 106 younger subjects (mean age = 23 years) using a customized device. MP optical density was measured in all subjects via customized heterochromatic flicker photometry.

Results

MP optical density was significantly (P < 0.05) related to reaction time and to balance ability for the older subjects. Even for the younger group, MP optical density was significantly (P < 0.05) related to fixed and variable position reaction time, as well as coincidence anticipation errors, at high speed.

Discussion

L and Z status has been linked to benefits in cognitive function in past research. The present results, and the selective presence of L and Z in visual and motor areas in the brain, are consistent with these carotenoids having a role in visual and motor integration.

Keywords:

• Lutein
• Macular pigment
• Spatial cognition
• Visuomotor function
• Zeaxanthin

Acknowledgements

Funding was provided by ZeaVision, L.C. The customized linear light display and associated software was developed by Kevin J. O'Brien, MS (University of Georgia Vision Sciences Laboratory).

Conflict of interest

Dr Renzi is currently employed by Abbott Nutrition, Columbus, OH. At the time of data collection and manuscript preparation, Dr Renzi was employed exclusively by the University of Georgia. No other authors report any conflicts of interest.