It has been asked before whether things (such as sugar, water, tea or condoms) that do not obviously involve the use of animal derivatives might or not be vegan. Here my question is about contact lenses. Are all of them vegan? Do any of them use any products that have been tested on animals?
As far as I know, there are no animal products involved in the production of contact-lenses. Whether they are vegan is debatable though and depends heavily on your definition of vegan.
The trouble with lenses is that they are often being tested on animals. While laws vary from country to country, there are countries and companies that do not test their lenses on animals and advertise so - you should be able to find them with a simple Google search. Unfortunately, as with many other products, most of the producers use at least some animal testing and so if the welfare of animals is an issue for you, you should always investigate the brand you intend to purchase.