Abstract
Purpose: :
Macular pigment optical density (MPOD) correlates strongly with glare resistance [Stringham, Optom. Vis. Sci. 2007; 84: 859-64] and weakly to faster glare recovery (GR) [Pratt 2002; ARVO E-Abstract 2540] in healthy subjects. Lutein (L) supplementation leads to improved GR in patients with age-related maculopathy [Richer 2003; ARVO E-Abstract 2540]. Furthermore, L supplementation correlates with improved pattern electroretinogram (PERG) amplitudes [Falsini, Ophthalmology 2003; 110:51-60], but its correlation to MPOD changes is not known. To our knowledge, neither the effects of L supplementation, nor those of L and zeaxanthin (Z) on other outcome measures of macular function have yet been studied. Therefore, the purpose of this study was to generate pilot data about the effects of L&Z supplementation on dark-adapted (DA) thresholds and recovery kinetics, pattern visual evoked potentials (PVEPs) before and after photo-stress, and PERG amplitude.
Methods: :
A White, male, 21-year old healthy subject participated in this experiment. The MPOD profile was measured with a previously reported instrument and protocol [Iannaccone et al. IOVS 2007; 8:1458-65] at 0.25, 0.5, 1 and 2 degs of eccentricity. The PERG P50 component was measured in response to 45-min arc checks alternating at 2Hz. The timing of the P100 component of the photo-stress PVEP was measured before, and its recovery to baseline (BL) values was measured at 15-sec blocks in response to a 22- and 11-min arc, 6.25-deg radius, circular stimulus after a full bleach (7.47 log scot td s, estimated to achieve a 97% rhodopsin bleach). Foveal DA thresholds before a bleach (same as above), and cone DA recovery kinetics (to cone plateau) after the bleach were measured in response to a 650nm DA stimulus. All measurements were obtained at BL, and the after 4 months of daily dietary supplementation with 20mg L and 0.9mg Z (Lutein caps, VitaminShoppe, North Bergen, NJ).
Results: :
Following L&Z supplementation, MPOD increased in each eye at all loci (mean MPOD: OD/OS BL: 0.26/0.28; OD/OS post-L&Z: 0.35/0.37; p = 0.004). These changes were accompanied by an increase in PERG P50 amplitude, as predicted by the study of Falsini et al., and by an increase in 650nm DA sensitivity (BL: 30dB; post-L&Z: 37dB), but no change in the cone recovery kinetics following the bleach or on photostress PVEP P100 recovery.
Conclusions: :
L&Z supplementation can result in improved macular function also in healthy eyes by both electrophysiological and psychophysical criteria.
Keywords: macula/fovea • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • electroretinography: clinical