Written by John Nolan, PhD
Carotenoids are a group of more than 700 pigments, ubiquitous throughout nature and synthesized de novo mainly by photosynthetic organisms (plants and algae). Three carotenoids in particular — lutein (L), zeaxanthin (Z) and meso-zeaxanthin (MZ) — make up the macular pigment (MP). Located in a central and prereceptorial location at the macula, the anti-inflammatory, antioxidant, and blue light-filtering properties of these macular carotenoids make them ideal candidates to not only help protect against age-related macular degeneration (AMD) but also enhance vision for all patients, including those who are young and healthy.
Filtering Blue Light
In terms of negative impact on visual performance, blue light exposure is a problem for everyone. The primary source of blue light comes from the sun, but now artificial sources of blue light include electronic devices such as cell phones and laptop computers, as well as energy-efficient fluorescent bulbs and LED lights. The light absorbance spectrum of MP peaks at 460nm and, therefore, this optical filter has the capacity to absorb/filter high-energy short-wavelength (blue) light before it reaches the photoreceptors (the cells of vision). Importantly, MP filtration occurs at the central retina only, which allows for blue light to reach the peripheral retina, where it impacts positively on sleep cycles, alertness, and mood. There are several reasons why blue light is deleterious for visual performance and experience. First, there are no blue sensitive cones at the centre of the fovea, thus, visible blue light cannot contribute to visual performance and experience at the location of maximum acuity. Second, given that only visible wavelengths of light are incident upon the retina, and because incident blue light is myopically defocused to an extent of 1.2 diopters, blue light actually contributes to chromatic aberration, which causes a blur around the image. Finally, and most importantly, it is only the blue wavelengths of light that are appreciably scattered and contribute to a phenomenon known as veiling luminance. MP is crucial, therefore, if the deleterious effect on visual performance of veiling luminance is to be minimized and vision is to be optimized.
Better Vision For All
Recently, the Central Retinal Enrichment Supplementation Trials (CREST)2 study, a double-blind, randomized, placebo-controlled trial, demonstrated that supplementation with the macular carotenoids in a MZ:L:Z (mg) ratio of 10:10:2 (i.e., MacuHealth LMZ3) versus placebo results in a statistically significant improvement in vision in subjects with a healthy macula. Furthermore, this formulation is shown to be superior, in terms of both MP augmentation and visual performance, when compared with alternative formulations lacking MZ.3
In other words, and for the first time ever, vision can be improved with simple over-the-counter supplementation, but the formulation must contain all three macular carotneoids. This discovery has particularly important implications for those who rely on their vision for professional reasons, such as athletes, pilots, and military marksmen, as well as for those who simply want to optimize their vision-related quality of life.
- The Vision Council. 2017 Blue Light/Digital Eye Strain Report. Available https://www.thevisioncouncil.org/sites/default/files/TVC_BlueLight_one-pager_FINAL.pdf. Last accessed Feb. 17, 2017.
- Nolan JM, Power R, Stringham J, et al.
- Akuffo KO, Nolan JM, Howard AN, et al. Sustained supplementation and monitored response with differing carotenoid formulations in early age-related macular degeneration. Eye (Lond). 2015;29(7):902-912.
Dr. Nolan is the Principal Investigator of the Macular Pigment Research Group at the Waterford Institute of Technology in Ireland. He specializes in the role of eye nutrition for vision and prevention of blindness, and the link between nutrition and brain health and function. He has presented at more than 100 international scientific conferences and has published more than 85 peer-reviewed scientific papers.