Wow, that's really cool! I had no idea our eyes can produce melanin to protect us from the sun. While it's always important to take precautions against excessive exposure to UV radiation and stay as protected from the sun as possible, that's an interesting thing to keep in mind during situations where you are getting some amount of sunlight along with being cautious. Although I wouldn't recommend anyone completely relying on their body's natural protection without any other safety measures such as sunscreen for a prolonged tim19e of exposed sunlight. Relatively safe exposure limits should be accounted for whilst going sunglasses-free again 😀 .