A lot of websites are selling dark lensed glasses designed to directly observe the solar eclipse that will pass over parts of the U.S. on August 21. But make sure you are getting glasses that are genuine, otherwise you could damage your eyes. According to NASA, you should check if your glasses fit these criteria:

• Have certification information with a designated ISO 12312-2 international standard
• Have the manufacturer’s name and address printed somewhere on the product
• Not be used if they are older than three years, or have scratched or wrinkled lenses
• Not use homemade filters or be substituted for with ordinary sunglasses — not even very dark ones — because they are not safe for looking directly at the Sun