Stuart Richer, Dong-Wouk Park, Rachel Epstein, James S. Wrobel and Carla Thomas
The risk of injury or fatality (driver, passenger or pedestrian) associated with motor vehicle accidents has been determined to increase with age, as a result of age-related declines in vision, motor and cognitive functioning. Elderly drivers with age related macular degeneration are particularly vulnerable to sensory visual impairment when driving at night, as they suffer declines in both Contrast sensitivity (CS) and Glare recovery (GR).
This study evaluates the relationship between carotenoid supplementation, CS and GR and the relationship between driving ability and retinal macular pigmentation.
Self-described driving performance is the basis of this report, with data derived from the Zeaxanthin and Vision Function (ZVF) Study (FDA IND #78,973), a 1 year, n=60, 4 visit, prospective randomized controlled clinical trial (RCT) of predominantly elderly male veterans (74.9 SD 10 y) with mild / moderate Age related Macular Degeneration (AMD). The twenty five question – National Eye Institute Visual Functioning Questionnaire (VFQ-25) v. January 2000, Rand Corporation® includes 3 questions assessing driving performance and were completed at baseline and 1 year after nutritional supplementation with approximately equal daily doses of the retinal macular carotenoids: lutein (9 mg) or zeaxanthin (8 mg). Replicate measures of foveal 1 degree estimated retinal macular pigment optical density were evaluated with the QuantifEye® (ZeaVision, Chesterfield, MO) heterochromic flicker photometer.
VFQ25 self-described driving ability was notably associated with baseline pre-supplementation macular pigmentation. Linear regression modeling suggests that self-described ability to safely drive a car was strongly associated with final macular re-pigmentation post supplementation (P=0.02). Moreover, the greatest effect was found with zeaxanthin (ns but P = 0.057 for trend) even though lutein had greater effects than zeaxanthin with respect to CS and GR, suggesting that unique zeaxanthin post-receptorial processes may be at play.
Carotenoid supplementation and subsequent macular repigmentation improved the self-described driving ability of patients with macular degeneration. Older male drivers with AMD should be encouraged to have their foveal macular MP measured at yearly eye examinations. If low macular pigment is found, these patients should attempt macular re-pigmentation via diet and/or supplementation to improve the sensory aspect of driving.