Steam eye masks are dangerous when applied for a long period of time, and may lead to incidents such as stinging eyes, redness and swelling of the eyelids, conjunctivitis, and burns of the cornea. 1. Eye stinging, eyelid redness and swelling: If the steam eye mask is too hot and burns the cornea, then you will feel eye stinging. Eyelid redness and swelling is mainly due to the direct contact between the eye mask and the skin, which produces an allergic reaction. 2. Conjunctivitis: Some people will use steam eye masks with makeup or wearing contact lenses, which is likely to trigger eye infections and lead to conjunctivitis. 3. Eye tissue damage: long-term steam eye mask, especially wearing a steam eye mask to sleep, there may be pressure on the eye, resulting in eye tissue damage, this is because the steam eye mask heat reaction is over, the iron powder inside will harden, fall asleep and turn around, inside the hardened iron powder will be friction with the tissues around the eye. The use of steam eye masks produce heat and steam, can indeed achieve to promote blood circulation in the eyes, relieve dry eyes, eyestrain effect, but must choose the regular products, standardized use, otherwise it is easy to cause damage to the eyes. If any discomfort occurs during the use of steam eye masks, be sure to seek medical attention.