You only get one pair of eyes so treat them right. Sunglasses are as important as sunscreen when you are planning to be outdoors on a sunny day for a prolonged period of time.
Cheap sunglasses that you buy from gas stations and drug stores may end up costing you big! Not all sunglasses offer adequate protection from ultraviolet light. One of the biggest misconception about sunglasses is the darker the lenses are, the more protection they offer against harmful rays. This is simply false.
If you've bought a cheap pair of sunglasses, the biggest danger is that they may be just tinted, but do not offer adequate UV protection. Darker tints cause the pupils to dilate and that causes more light to enter the eyes. Regular exposure to UV light can have profound consequences to the eyes and skin.
Solar radiation reaching the earth consists of electromagnetic energy ranging from ultraviolet (UV) light to infrared (IR) light. UV radiation is divided into three types: UVA, UVB, and UVC. UVC radiation is absorbed by the earth's atmosphere, so we won't talk about that. UVB on the other hand is known to cause skin cancer in humans. UVA has been found to play some role in skin cancer and a major role in eye cataracts, solar retinitis, and corneal dystrophies.
Remember the following terms when shopping for new sunglasses: UV protection and polarization. Sunglasses should offer 99 to 100 percent protection against both UVA and UVB rays. Some sunglasses such as Mosley Tribes Carden take protection a step further, and offer an anti-reflective treatment on the backside of the lenses to help stop light hitting the back of the lenses from reflecting into the eyes. As much as 50% of unwanted UV rays can enter the eyes through reflection.
Wraparound style sunglasses are always recommended for outdoors sports, especially watersports. These styles perform much better since the lenses are wrapped around the eyes and most of reflection is eliminated. At Trovelle, we only carry sunglasses that offer 100% UVA and UVB protection.
Your optician may be able to test the UV protection of your sunglasses. Testing UV protection at home is pretty simple too. All you need is your sunglasses, a UV flashlight and paper money. Shine the UV flashlight at your paper money to reveal the security elements as they will appear to glow when exposed to UV light. You might need to do this indoors in a darker area. Now, do the same thing again, only this time, pass the UV light through your sunglasses lenses onto the paper money. The security elements should no longer glow.
In conclusion, sunglasses are not bad for your eyes and are meant to protect them from prolonged sun exposure. Sunglasses are not meant to be worn all the time. You should not wear your sunglasses in the shade, on a cloudy day, at night or indoors. Remember, your eyes and body need natural light from the sun for many other health reasons. For more information about this topic, you may want to check out the using light to optimize health episode from the Huberman Lab Podcast.