Macular carotenoid supplementation improves disability glare performance and dynamics of photostress recovery

Background:The so-called macular carotenoids(MC)lutein(L),zeaxanthin(Z),and meso-zeaxanthin(MZ)comprise the diet-derived macular pigment(MP).The purpose of this study was to determine effects of MC supplementation on the optical density of MP(MPOD),repeated-exposure photostress recovery(PSR),and disability glare(DG)thresholds.Methods:This was a double-blind,placebo-controlled trial.Fifty-nine young(mean age=21.7),healthy volunteers participated in this study.Subjects supplemented their daily diet with either 10 mg L+2 mg total Z(1 mg Z+1 mg MZ;n=24),20 mg L+4 mg total Z(2 mg Z+2 mg MZ;n=25),or placebo(n=10)for 12 months.The primary outcome was a composite measure of visual performance in glare,defined by change in DG and PSR.Secondary outcomes included MPOD and visual fatigue.The primary endpoint for outcomes was 12 months.MPOD was assessed with customized heterochromatic flicker photometry.PSR times for an 8 cycle/degree,15%contrast Gabor patch target were determined after each of five successive exposures to intense LED lights.DG threshold was defined as the intensity of a ring of lights through which subjects were able to maintain visibility of the aforementioned target.Measures of all parameters were conducted at baseline,6 months,and 12 months.Repeated-measures ANOVA,and Pearson product-moment correlations were used to determine statistically significant correlations,and changes within and between groups.Results:MPOD for subjects in both supplementation groups increased significantly versus placebo at both 6-and 12-month visits(p<0.001 for all).Additionally,PSR times and DG thresholds improved significantly from baseline compared to placebo at 6-and 12-month visits(p<0.001 for all).At baseline,MPOD was significantly related to both DG thresholds(r=0.444;p=0.0021)and PSR times(r=-0.56;p<0.001).As a function of MPOD,the repeated-exposure PSR curves became more asymptotic,as opposed to linear.The change in subjects’DG thresholds were significantly related to changes in PSR times across the study period(r=-0.534;p<0.001).Conclusions:Increases in MPOD lead to significant improvements in PSR times and DG thresholds.The asymptotic shape of the repeated-exposure PSR curves suggests that increases in MPOD produce more consistent steady-state visual performance in bright light conditions.The mechanism for this effect may involve both the optical filtering and biochemical(antioxidant)properties of MP.Trial registration:ISRCTN trial registration number:ISRCTN54990825.Data reported in this manuscript represent secondary outcome measures from the registered trial.

The effects of sun exposure on carotenoid accumulation and oxidative stress in the retina of the House Finch(Haemorhous mexicanus)

Background: Diet-derived carotenoid pigments are concentrated in the retinas of birds and serve a variety of functions, including photoprotection. In domesticated bird species(e.g., chickens and quail), retinal carotenoid pigmentation has been shown to respond to large manipulations in light exposure and provide protection against photodamage. However, it is not known if or how wild birds respond to ecologically relevant variation in sun exposure.Methods: We manipulated the duration of natural sunlight exposure and dietary carotenoid levels in wild-caught captive House Finches(Haemorhous mexicanus), then measured carotenoid accumulation and oxidative stress in the retina.Results: We found no significant effects of sun exposure on retinal levels of carotenoids or lipid peroxidation, in replicate experiments, in winter(Jan–Mar) and spring/summer(May–June). Dietary carotenoid supplementation in the spring/summer experiment led to significantly higher retinal carotenoid levels, but did not affect lipid peroxidation. Carotenoid levels differed significantly between the winter and spring/summer experiments, with higher retinal and lower plasma carotenoid levels in birds from the later experiment.Conclusion: Our results suggest that variation in the duration of exposure to direct sunlight have limited influence on intraspecific variation in retinal carotenoid accumulation, but that accumulation may track other seasonal–environmental cues and physiological processes.

Rapid retinal functional testing

The most prominent causes of loss of vision in individuals over 50 years include age-related macular degeneration(AMD),glaucoma,and diabetic retinopathy(DR).While it is important to screen for these diseases effectively,current eye care is not properly doing so for much of the population,resulting in unfortunate visual disability and high costs for patients.Innovative functional testing can be unified with other screening methods for a more robust and safer screening and prediction of disease.The goal in the creation of functional testing modalities is to develop highly sensitive screening tests that are easy to use,accessible to all users,and inexpensive.The tests herein are deployed on an iPad with easily understood and intuitive instructions for rapid,streamlined,and automatic administration.These testing modalities could become highly sensitive screenings for early detection of potentially blinding diseases.The applications from our collaborators at AMA Optics include a cone photostress recovery test for detection of AMD and diabetic macular edema(DME),brightness balance perception for optic nerve dysfunction and especially glaucoma,color vision testing which is a broad screening tool,and visual acuity test.Machine learning with the combined structural and functional data will optimize identification of disease and prediction of outcomes.Here,we review and assess various tests of visual function that are easily administered on a tablet for screening in primary care.These user-friendly and simple screening tests allow patients to be identified in the early stages of disease for referral to specialists,proper assessment and treatment.

光照黄斑部试验的临床研究─—眼底病患者MPT的改变及其机理的探讨

７９只眼底病患眼的光照黄斑部试验（ＭＰＴ）结果显示：中心性浆液性脉络膜视网膜病变、老年性黄斑变性渗出型和Ｒｉｅｇｅｒ型中心性渗出性脉络膜视网膜病变患眼的光照黄斑恢复时间显著延长，其它黄斑部病变患眼也有不同程度的延长。本文结合眼底荧光血管造影和黄斑视野域值试验对光照黄斑部试验的机理进行了探讨。