Macular Pigment: Lutein, Zeaxanthin and AMD Risk

Macular pigment is a yellow layer of carotenoids at the center of the retina.

It consists of lutein, zeaxanthin and meso-zeaxanthin.

Therefore, it is the retina’s own filter for blue light and a store of antioxidants.

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What Macular Pigment Is

The pigment sits in the Henle fiber layer and the inner retina of the fovea.

Its concentration is highest at the foveal center.

Also, the human body cannot make these carotenoids, so they come from food.

As a result, diet shapes the amount of pigment.

Composition of Macular Pigment

Lutein and zeaxanthin enter from the blood through the choroid.

Meso-zeaxanthin forms in the retina from lutein.

Also, the ratio changes with eccentricity: zeaxanthin forms are more central.

Therefore, the central fovea contains the highest concentration of meso-zeaxanthin.

How Macular Pigment Protects the Retina

The pigment absorbs blue light with a peak at about 460 nanometers.

This reduces light damage and chromatic aberration.

Also, it quenches reactive oxygen species.

As a result, it protects photoreceptors and the pigment epithelium.

Dietary Sources

Dark leafy vegetables such as kale and spinach are rich in lutein.

Egg yolk, corn and peppers also contain carotenoids.

Also, fat in the meal improves absorption.

Therefore, a diet rich in vegetables supports macular pigment.

Measuring Macular Pigment

Heterochromatic flicker photometry measures the pigment by a subject’s own response.

Autofluorescence with two wavelengths maps the optical density in the fundus.

Also, resonance Raman spectroscopy measures the carotenoids directly.

In addition, fundus reflectometry offers a fast option.

Why the Optical Density Varies

Macular pigment optical density varies widely between people.

Age, smoking, obesity and diet explain part of it.

Also, genes affecting carotenoid transport play a role.

As a result, two people with the same diet can have different pigment levels.

Macular Pigment and AMD

Eyes with age-related macular degeneration have lower pigment density in many studies.

The pigment declines with age and with smoking.

Also, low dietary intake is linked to higher risk of late AMD.

Therefore, the pigment is a biomarker and perhaps a modifiable factor.

What AREDS2 Showed About Macular Pigment

AREDS2 tested lutein 10 mg and zeaxanthin 2 mg added to the original formula (see AREDS2 supplements).

The overall risk of late AMD did not fall significantly.

Also, a secondary analysis showed benefit in people with low dietary intake.

As a result, the supplement became the standard replacement for beta-carotene.

Supplements in Practice

Recommend the AREDS2 formula to patients with intermediate AMD or late AMD in one eye.

It is not meant for people with early disease only.

Also, smokers should avoid beta-carotene, which is why the newer formula omits it.

Therefore, match the product to the stage.

Macular Pigment and Visual Function

Higher pigment is linked to better contrast sensitivity and less glare disability.

Studies show faster recovery after bright light exposure.

Also, trials of supplements in healthy people show modest changes in visual performance.

In addition, the effect on dark adaptation remains unclear.

Macular Telangiectasia and Pigment Loss

Macular telangiectasia type 2 shows loss of macular pigment at the foveal center.

The optical density map helps in diagnosis.

Also, the Müller cells that store the pigment are affected.

Therefore, pigment imaging can support the diagnosis.

Pigment in Children and Infants

Infants receive carotenoids from breast milk and formula.

Premature infants have less macular pigment.

Also, the foveal pit forms before the pigment accumulates.

As a result, early nutrition may matter for retinal development.

Smoking and Macular Pigment

Smokers have lower pigment density and higher AMD risk.

Quitting may restore part of the pigment over time.

Also, passive smoke exposure may add to the risk.

Therefore, smoking cessation advice belongs in every visit.

Blue Light and Screens

Screens emit blue light, but at levels far below sunlight.

No clear evidence shows that screens harm the macula.

Also, blue-blocking lenses have not proven helpful for retinal protection.

Therefore, advise good lighting and breaks, and skip special glasses.

Counseling Patients

Tell patients to stop smoking and eat vegetables daily.

Explain that supplements help those with intermediate disease.

Also, avoid promises of cures.

In addition, remind them to check vision with an Amsler grid.

Pitfalls to Avoid

• Do not recommend lutein pills to every patient without AMD
• Never use beta-carotene products in smokers
• Do not treat optical density as a diagnostic test for AMD
• Never replace anti-VEGF therapy with supplements

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References

1. Bernstein PS, Li B, Vachali PP, et al. Lutein, zeaxanthin, and meso-zeaxanthin: the basic and clinical science underlying carotenoid-based nutritional interventions against ocular disease. Prog Retin Eye Res. 2016;50:34-66.
2. Landrum JT, Bone RA. Lutein, zeaxanthin, and the macular pigment. Arch Biochem Biophys. 2001;385:28-40.
3. Bone RA, Landrum JT, Fernandez L, Tarsis SL. Analysis of the macular pigment by HPLC: retinal distribution and age study. Invest Ophthalmol Vis Sci. 1988;29:843-849.
4. Age-Related Eye Disease Study 2 Research Group. Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the AREDS2 randomized clinical trial. JAMA. 2013;309:2005-2015.