Interest in visible light’s ability to induce pigmentation in the skin began in the 1980s, when research suggested that visible light had a similar effect as UV-A.1,2 Then, in 2010, Mahmoud et al3 published a seminal paper suggesting that visible light had the ability to induce pigmentation and moreover sustained pigmentation, particularly in darker racial ethnic groups. This group, led by Dr Henry Lim at Henry Ford in Detroit, MI, has been at the forefront of assessing the impact of visible light on pigmentation and its overall cutaneous impact. Medicine is now to the point that investigators have worked out the pathway through which visible light induces hyperpigmentation.4 Visible light activates the Opsin-3 receptor on melanocytes, which triggers a calcium-dependent pathway that then upregulates MITF, the master switch for pigment production and tyrosinase, but it also activates a complex of tyrosinase and dopachrome tautomerase that seems to drive the pigment process.4
Historically, we know that zinc oxide and titanium dioxide can block out visible light, but when micronized, they do lose this ability. In the work I have recently been a part of as an investigator for Dermablend and L’Oreal,5 we looked at the impact of our metal oxide formulations and their ability to decrease pigmentation induced by visible light in skin of color.
We recruited 10 healthy individuals, Fitzpatrick phototype IV, with a mean age of 35 years. Participants needed to avoid UV exposure (whether sunlight, sunbeds, or laser/phototherapy to the back) beyond regular activities or over the time of participation in the study and could not have any photosensitive disorders. On each of these participants, we created five squares on the midback: one of the squares was untreated, one was exposed to visible light without protection, one was treated with a standard SPF 50 mineral sunscreen containing titanium dioxide and zinc oxide, and the last two squares each received a different formulation of a topical cosmetic foundation (iron oxide only, and iron oxide plus titanium dioxide). Squares were treated at baseline and on days 1, 2, and 3, and they were subsequently observed at day 4 and day 14. The sites were irradiated with visible light 15 minutes later at 144 J/cm2, which is equivalent to an hour of midday sun exposure. The squares were graded by visual assessment on a pigmentation scale (0 = no pigment, 13 = significantly brown pigment). Photographs were taken at each visit and colorimetry measurements were taken using the Minolta chromameter.
The study5 showed that the two formulations of the topical cosmetic foundation significantly reduced the effects of visible light-induced pigmentation vs mineral sunscreen and control. This was fascinating, because it suggested that clearly these cosmetic formulations had the ability to do two things: serve as a cosmetic camouflage and also block out visible light.
Now, why is this so important long term? If you look at where we are in understanding the significance of the science, visible light encompasses roughly 45% of the electromagnetic spectrum; moreover, we are exposed to artificial sources every single day, especially in this COVID-19 era with our phones, our computer screens, and our televisions. We think that visible light is a major player in driving that sustained or difficult-to-treat pigmentation in patients who have melasma, postinflammatory hyperpigmentation, or the dyschromia of photoaging. Visible light also induces oxidative stress and inflammation, and it can damage DNA, which is just one aspect of its deleterious aging effects.
This latest research,5 which in my opinion was a proof-of-concept study, lets us know that these tinted iron oxide cosmetic formulations can block visible light. Now we have to ask how we take this data and expand, massage, and make it work even better for us as clinicians.
Telling Patients About Visible Light
Visible light is an ongoing conversation for me now, particularly in my patients who come in for hyperpigmentation. The conversation usually begins with what they know about photoprotection, and that is usually UV protection. From there, the next phase is to talk about the missing link, and so that is my introduction to talking about the electromagnetic spectrum. My patients are pretty sophisticated; they read a lot and they will come in and ask me questions. I then engage them on what we have learned as scientists and visible light’s ability to induce this chronic, sustained pigmentation that makes melasma and other disorders more difficult to treat.
We address the basic question of “what do we do about it?”, but unfortunately, we do not have great options. As multiple companies now jump on board to offer visible light protection, the science unfortunately is not there yet. We oftentimes do not know how much iron oxide is in a product. Products may contain other ingredients that supposedly have the ability to block visible light, but we just do not have the science to back that up. We think it takes about 3.5% iron oxide to get some visible light protection.
So, what I typically do with my patients with hyperpigmentation, vitiligo, or other pigmentary issues is one-on-one education. I educate them on their disease so that they can understand and embrace it, then we move forward with treating it. I oftentimes talk about the topical cosmetic foundations we studied in the Journal of Drugs in Dermatology article.5 We discuss how I have been studying this product and that the science is now there, and applying the makeup is one of the easiest things you can do. Patients can even mix it with their sunscreen or their existing foundation, so at the end of the day, they have a path to get some visible light protection. I find that once I take the time to explain the data for them, they are on board. They want sustainability, long-term improvement, outcomes, and no relapse. As I said, given the new lifestyle and new paradigm of how we live and how we communicate, I think is more important than ever to take steps to protect from visible light.
But the stark reality is as dermatologists, we want multiple products to offer our patients. I sincerely hope that more cosmetic and cosmeceutical companies engage this science so that we can move forward with well-designed clinical studies. There are so few studies right now that look at visible light protection vs UV protection to delineate the mitigating effects on pigmentation. We need more data to continue to tease out the science.
Further Implications for Skin of Color
Patients of color are often misinformed or misunderstand their needs for photoprotection. Dermatologists already know that skin of color is not immune to the DNA damage or oxidative stress caused by visible light. A treatment or cosmetic intervention for visible light allows us to address all the deleterious aspects beyond pigmentation. However, pigmentation in your darker skin types is more of a sustained problem and more difficult to treat.
I recommend dermatologists ask their patients with darker skin types about their cosmetic issues of concern when they come in. In our patients with Fitzpatrick I through III skin, we are typically looking at fine and coarse lines and other signs of aging. But my patients with Fitzpatrick IV through VI skin, and in particular V and VI, most often request that I even and smooth out texture and correct hyperpigmentation. They want to be flawless; they want to be able to go out without makeup if they do not want to apply it.
Closing Thoughts
Recently, there really have been some seminal and key contributions to our understanding of the cutaneous impact of visible light. Kudos to all the scientists who have been on the ground floor and have played a major role in moving this science forward. Can we do more? Absolutely. We need more basic science research to address what visible light may be upregulating regarding signaling pathways or what it may be downregulating. Furthermore, there is a dearth of data on the impact of visible light in clinical scenarios. Our recent study5 simply looked at the impact of visible light in subjects on test squares on the back. We now need to take tinted iron oxide formulations that blocked out visible light and look at what they do by themselves in a long-term clinical trial.
We just published a paper in Journal of Drugs in Dermatology that compared the 1-year outcomes of sunscreen use in a group of Hispanic women with Fitzpatrick IV and V skin.6 We had two groups of patients: one who used daily sunscreen for photoprotection and the other did not. There was a significant difference after a year in the group who wore sunscreen; this group had significant clinical improvements in dyschromia-related parameters on multiple areas of the face. I would be very interested in knowing what happens to pigmentation if we protect against visible light for a year.
When it comes to pigment disorders, we may be able to make an enormous difference and keep patients in remission for a much longer period if, again, we can expand on the current data by further optimizing the aforementioned formulations. We have indeed moved the science forward. However, there is still an enormous amount of work to be done to be able to really situate our approaches to block the deleterious effects of the UV light, visible light, and even infrared light that we deal with on a daily basis.
Dr Grimes is the director of the Vitiligo & Pigmentation Institute of Southern California and of the Grimes Institute for Medical and Aesthetic Dermatology in Los Angeles, CA.
Disclosure: Dr Grimes serves as a consultant for VT Cosmetics, Incyte, and Dermaforce as well as an investigator for Pfizer, L’Oreal, Johnson & Johnson, Clinuvel, VT Cosmetics, and Incyte.
References
1. Kollias N, Baqer A. An experimental study of the changes in pigmentation in human skin in vivo with visible and near infrared light. Photochem Photobiol. 1984;39(5):651-659. doi:10.1111/j.1751-1097.1984.tb03905.x
2. Porges SB, Kaidbey KH, Grove FL. Quantification of visible light-induced melanogenesis in human skin. Photodermatol. 1988;5(5):197-200.
3. Mahmoud BH, Ruvolo E, Hexsel CL, et al. Impact of long-wavelength UVA and visible light on melanocompetent skin. J Invest Dermatol. 2020;130(8):2092-2097. doi:10.1038/jid.2010.95
4. Regazzetti C, Sormani L, Debayle D, et al. Melanocytes sense blue light and regulate pigmentation through Opsin-3. J Invest Dermatol. 2018;138(1):171-178. doi:10.1016/j.jid.2017.07.833
5. Dumbuya H, Grimes PE, Lynch S, et al. Impact of iron-oxide containing formulations against visible light-induced skin pigmentation in skin of color individuals. J Drugs Dermatol. 2020;19(7):712-717. doi:10.36849/JDD.2020.5032
6. Grimes P, Halder R, Verschoore M, et al. Long-term benefits of daily photo-protection with a broad-spectrum sunscreen in United States Hispanic female population. J Drugs Dermatol. 2020;19(3):236-242. doi:10.36849/JDD.2020.4836
