Dear Natural Health Friends,

I came across a post this week from Dr. AmmousMD that really made me stop and think. He explained that your body relies on UV signals reaching your eyes to trigger melanin production—the pigment that gives you a tan and helps protect your skin from burning. When you block those signals with sunglasses, you may actually increase your risk of sunburn because your body doesn’t get the message to ramp up its natural defense. (Here’s the link to the article on PubMed that he was referencing.)

Sunlight is a Nutrient

As a holistic nutritionist, I’ve been learning more and more to view sunlight as one of the body’s most powerful “nutrients.” Just like the right foods support hormone balance, energy, and repair, the right light signals do the same—helping regulate circadian rhythms, melatonin, cortisol, and even how your cells produce energy.

The Effect of Blocking Natural Sunlight on the Eyes

Blocking key parts of the sun’s spectrum with sunglasses can quietly disrupt the valuable information our eyes take in from sunlight. I’ll be honest: I’ve never worn sunglasses regularly. With my prescription, it was always too much hassle to keep two pairs (regular and sunglasses) and switch them out. So, I just squint when I’m out in the sun. For years I wondered if that was “bad” for my eyes. Reading Dr. AmmousMD’s post made me realize my habit might actually align better with how our bodies are designed to handle natural light!

Squinting isn’t perfect, of course, but at least it doesn’t completely block the UV cues your eyes (and brain) need.

And you can read up on how to protect your skin from sunburn (with nutrition!) here.

So—What About Blue-Light Blockers?

This got me thinking about another common light-related tool many of us use: blue-light-blocking glasses. You’ve probably seen them marketed for screen time—clear or lightly tinted lenses that filter out blue wavelengths from phones, computers, and LED lights. I’ve been musing about the best way to use them, especially for those of us with prescriptions who might consider adding a blue-light-blocking coating to our everyday glasses.

Here’s my question: Could wearing blue-light-blocker-treated prescription glasses all day long interfere with the important light messages your brain needs in the morning?

Why We Need Natural Morning Sunlight

Morning light—particularly the blue wavelengths in natural sunlight—helps set your circadian clock. It signals alertness, supports healthy cortisol rhythms, and prepares your body for the day. Blocking too much of that could send mixed signals to the suprachiasmatic nucleus (your master clock in the brain), potentially affecting sleep later, mood, and even metabolic health.

The science backs this up. A 2022 review in the journal Chronobiology International concluded that while blue-light-blocking lenses in the evening can help protect melatonin and improve sleep, using them during the daytime is not recommended. Daytime blue light is beneficial—it helps synchronize your circadian rhythm, boosts alertness, and supports cognitive function. The authors noted that evidence for negative effects from reducing blue light during the day is stronger than any benefits from wearing the lenses around the clock.

​Harvard Health Publishing echoes this: “Exposure to blue light during the daytime is desirable: it helps synchronize the body’s circadian clock and helps people stay alert.”

In contrast, blue light at night is the real culprit for melatonin suppression and disrupted sleep. That’s why many sleep researchers recommend blue blockers only in the evening—ideally 2–3 hours before bed—or specifically for screen use after sunset.

Practical takeaway for us prescription-wearers? Consider two separate solutions instead of an all-day coating:

• Keep your regular prescription glasses for daytime (especially morning outdoor time).
• Use a dedicated pair of blue-light-blocking glasses (or clip-on filters) only in the evening for screens or indoor artificial light.

This way you get the full benefit of natural daylight signals without the evening disruption.

If you already have blue-blocker coatings on your everyday lenses, it might be worth discussing an uncoated pair for daytime use with your optometrist. Small shifts like this—protecting your eyes from unnecessary blocking while being intentional about evening light—can support the same systems we target with nutrition: better hormone balance, steadier energy, and deeper sleep. Light, not just food, is information for your body!

Have you tried adjusting your sunglasses or blue-light habits? I’d love to hear what’s worked for you—reply and let me know. In the meantime, try getting 10–20 minutes of natural morning light without sunglasses this week and notice how you feel. My action step is going to be taking my glasses off every time I don’t need them when I’m outside.

Sincerely yours,

Laura Sheehan, MSACN, Holistic Nutritionist