You are constantly exposed to blue light, both indoors and outdoors. Sources of blue light include:
How does blue light affect your eyes?
Our eyes are not good at blocking blue light. Virtually all visible blue light passes through the cornea and lens, and reaches the retina. With its short and high energy wavelengths, it scatters more easily, and is not easily focused. This causes reduced visual contrast, which can lead to digital eye strain. Symptoms of digital eye strain include dry or irritated eyes, headache and blurred vision. Long-term exposure to blue light has been linked to increased risk of developing age-related macular degeneration (AMD), which is the leading cause of vision loss.
Macular pigment and its contribution to vision
The macula is the most sensitive part of the retina, responsible for sharp, detailed central vision, and colour discrimination. It is made up of three xanthophyll carotenoids, lutein (L), zeaxanthin (Z) and meso-zeaxanthin (MZ), which are collectively known as macular pigment (MP). This yellow-coloured MP protects the delicate photoreceptor cells in the retina.
Increases the macular pigment optical density (MPOD) for enhanced visual performance, including visual acuity, contrast sensitivity, glare sensitivity and photo-stress recovery.
Serves as internal sunglasses to filter out hazardous blue light, protecting the macula against AMD.
Acts as a potent antioxidant to protect the eyes from free radicals which cause oxidative stress.
What are the sources of L, Z and MZ?
Of the many types of carotenoids in your body, only L, Z and MZ are deposited in the macula. L and Z cannot be synthesised by your body; they can, however, be obtained through the diet. Foods rich in L and Z include kale, spinach, turnip greens, green peas, broccoli, corn and eggs.
Unlike L and Z, MZ is not present in a typical diet. It is produced in the retina from L via an isomerisation process. However, this process is disrupted as you age. It is therefore essential to replenish these carotenoids, particularly MZ, through supplementation.
Why do we need all the three L, Z and MZ?
The different absorption spectra of L, Z and MZ results in a collective optimal filtration of blue light at the macula, which would not be achieved by any of these carotenoids in isolation. Studies have also shown that the inclusion of MZ resulted in a greater increase in MPOD in comparison to supplements lacking this central carotenoid.
MZ accounts for about one third of total MP at the macula. It resides directly over the center of the macula, where light is focused and where the strongest need for blue light protection exists. Moreover, of the three carotenoids, MZ has the greatest capability of quenching oxygen radicals. It has the capacity to filter the most energetic and potentially damaging wavelengths of visible light, and to neutralise free radicals produced by oxidative stress.
Supplementing with L, Z and MZ
You are never too young to start a proactive measure to protect your vision down the road. As most of us do not get enough of these carotenoids just from diet alone, supplementation can be another, more promising way of raising the MPOD, particularly if you spend long hours in front of a computer, digital gadget or television, play sports and spend long hours in bright light focusing on small objects, or are distracted by lights during night-time driving.
Not all macular carotenoid supplements are made the same. For optimal efficacy, look for a supplement containing the new, improved XanMax® formulation which features double-strength (200mg) marigold extract. It is standardised to deliver the highest amounts of L, Z and MZ compared to regular eye supplements.