Sports glasses will fog up because they are at a lower temperature than the heat that is being emitted by your face. When the heat from your face hits the glasses, the lower temperatures cause the air to condensate and the moisture turns to a liquid on the glasses. The amount of fogging that will occur will be determined by temperature differences and how much moisture is in the air.
What Causes the Glasses to Fog?
The colder the temperature is, the more likely your glasses will fog. A big temperature difference can cause the glasses to fog up even more, no matter what the moisture level is in the air. When its humid outside, it causes water droplets to form at lower temperature differences. This is why glasses will almost always fog with humidity. Raining is similar to when it's humid out since there is a lot of moisture in the air. The rain on the glasses can also cool them down, which will add to the temperature difference. While all glasses can fog, sports glasses tend to fog up more because they provide more protection and are closer to the face. Glasses that are closer to the face decrease the amount of air that flows through them to dissipate the heat. Working hard will cause your body to heat up and you produce sweat. The added moisture and heat contribute to more lens fogging.
Should You Have an Anti-Fog Coating?
There are lenses that come with an anti-fog coating. The anti-fog coating works by blocking moisture that sticks to the lenses. You can get this at the optical clinic or store where you are purchasing your glasses. It can either be permanent or temporary. If you decide to get anti-fog coating then you will need to not touch or wipe the lenses since this can cause the coating to peel off. Even if it's a permanent coating, the coatings to tend to wear unevenly with use and then it can be difficult to see out of your glasses. Coatings can't be replaced so the only way to fix this is to replace the lenses entirely.
What Else You Can Do
If you have an issue with your sports glasses fogging up, there are different things you can try instead of an anti-fog coating.
Change the Eyewear Design: Finding sports glasses that allow more airflow around the lens may be what you need to reduce or delay fogging.
Position Glasses Further Away from the Face: If you can't change your eyewear design then try to position glasses further away from the face to let the air flow between your lenses and your skin. Some eyeglasses may be fitted with an adjustable nose-piece in order to help with this problem.
Use Anti-Fog Wipes: If the glasses don't have anti-fog coating then you can do this with wipes. These solutions are quite handy and are formulated with compounds that prevent the water droplets from forming on the lenses. The anti-fog wipes offer the same anti-fog performance as the coatings but don't stay on the lenses so they won't affect the lenses in the same way and cause issues.
Choose Your Weather Accessories Carefully: If it's raining, you don't want to bundle yourself up in clothing that causes air to be trapped around your glasses. This may mean you have to avoid face-masks and scarves. If you can't stand the weather without a scarf on then choose one that is course enough to let the air pass through.
Avoid Abrupt Temperature Changes: It can help to wait before you go from cold to hot areas in order to prevent fogging. Upon entering a building, stand in the doorway for a minute or two.
By using some of these techniques, you will be seeing clearly whatever sport or activity you are enjoying. At Goggles N More we carry prescription sports glasses that will suit your needs for every sport.