QWhat are the clinical implications of visible light?

Medically reviewed on 05.01.2024 by Aaron Farberg, MD

As a dermatology PA, sunscreen is something that I recommend daily in clinical practice. We know that sunscreen is imperative for preventing sunburn, precancer, skin cancer, and reducing signs of aging accelerated by ultraviolet (UV) radiation. Historically, UV filters have focused on the ultraviolet spectrum, most notably UVA (320-400 nm), implicated in premature aging, and UVB (290-320 nm), implicated in sunburns and skin cancer formation.

Over the last several years, however, there has been a greater understanding and emphasis on the effects of visible light. So, what is visible light, and why is it so important? Well, visible light accounts for nearly 50% of sunlight that reaches the skin (wavelengths 400-700 nm).¹ Visible light also comes from artificial sources like our computer screens and overhead lights.² Studies have shown that visible light can exacerbate melasma, post-inflammatory erythema, and post-inflammatory hyperpigmentation.¹

When counseling our patients on photoprotection in cases of PIE and PIH from pre-existing acne or in cases of melasma, we need to know which sunscreens will provide the greatest benefits. Not all sunscreens are created equally. In fact, the relevance of visible light was noted when evaluating relapses in women with melasma when certain sunscreens were used.¹ Upon further evaluation, it was discovered that the lower range of visible light (blue-violet light or approximately 415 nm) resulted in greater pigmentation in those with skin of color.¹ We must remember that skin of color is more prone to hyperpigmentation, and the hyperpigmentation tends to persist for longer, making sunscreen selection of vital importance.

Let’s move on to discuss specific formulations that you can recommend in your clinical practice. First and foremost, tinted sunscreens designed to combat the harmful effects of UV radiation have the added benefit of pigmentary titanium dioxide and iron oxide.² These render the product tinted and block visible light. These formulations can also help to camouflage imperfections. A few of my personal favorites to wear and recommend are SkinCeuticals Physical Fusion UV Defense SPF 50 and La Roche-Posay Anthelios Tinted Mineral Light Fluid Sunscreen with SPF 50. These formulas are also very lightweight and elegant to wear alone or under cosmetics. Please note that an SPF 50 or above provides greater benefit for pigmentary disorders.

The “tint” in these SPFs are created by mixing varying amounts of yellow, black, and red iron oxides with pigmentary titanium dioxide.² It may require some trial and error to find the best tinted sunscreen for each individual skin tone.

In addition to tinted sunscreens, antioxidant-containing sunscreens can also help to combat photoaging and dyspigmentation but by a different mechanism. Reactive oxygen species have been shown to promote melanogenesis.³ By using antioxidants to scavenge reactive oxygen species, these formulations can help to protect against dyschromia. Eucerin Oil Control SPF 50 with 5 AOX Shield is a product that I recommend daily, especially in those patients not willing to wear a tinted SPF. This product harnesses the power of licochalcone A, glycyrrhetinic acid, oxynex ST, vitamin E, and vitamin C to combat free radicals, DNA damage, and skin pigmentation. This is one of my favorites for my patients with acne vulgaris who are dealing with the sequelae of acne (postinflammatory hyperpigmentation and postinflammatory erythema). Combined with traditional acne therapeutics, this can be quite impactful.

Over the years, we have seen an explosion of novel sunscreens, each seeking to offer consumers cosmetic elegance, wearability, and added benefits such as protection against visible light. This is just the beginning. I look forward to new sunscreen formulations aimed at combating sunburns, skin cancer, aging, and pigmentation. We all know that the best sunscreen is the one we will actually wear consistently.

References:

1. Rigel DS, Taylor SC, Lim HW, et al. Photoprotection for skin of all color: Consensus and clinical guidance from an expert panel. J Am Acad Dermatol. 2022;86(3S):S1-S8. doi:10.1016/j.jaad.2021.12.019
2. Nathan N, Manstein D. Tinted sunscreens: Benefits beyond an attractive glow. Harvard Health. July 13, 2020. Accessed June 11, 2024. https://www.health.harvard.edu/blog/tinted-sunscreens-benefits-beyond-an-attractive-glow-2020071320534.
3. Taylor SC, Alexis AF, Armstrong AW, Chiesa Fuxench ZC, Lim HW. Misconceptions of photoprotection in skin of color. J Am Acad Dermatol. 2022;86(3S):S9-S17. doi:10.1016/j.jaad.2021.12.020