All contact lens are potentially damaging. In the United States, regular contacts need a prescription by a certified optometrist to be obtained because they need to be specially fit to your own eyeball. Cosmetic lenses that have 0.00 power (plano lenses) are legal to sell in the USA without prescription, but most stores require one anyways.
But the “largeness” of the lenses are relative – brands in America sell contacts with 14.00-14.60 diameter. Circle lense brands are the same. If you wear contacts already, check the information on your own lenses to determine if the circle lenses you want are the proper fit for you.
Almost all circle lenses sold throughout Asia are imported from Korea. Big name brands are usually FDA and CE approved. There are some smaller, unknown companies that produce the lenses, but they are not approved. Most of those companies are non-Korean brands, though not all. Do not buy them if you are unwary of the brand or seller! Always ask the seller all questions before buying