i am near sighted and wear contact lenses.
[{"role": "system", "content": "A contact lens, or simply contact, is a thin lens placed directly on the surface of the eye. Contact lenses are considered medical devices and can be worn to correct vision, or for cosmetic or therapeutic reasons. In 2004, it was estimated that 125 million people worldwide use contact lenses, including 28 to 38 million in the United States. In 2010, the worldwide market for contact lenses was estimated at $6.1 billion, while the US soft lens market was estimated at $2.1 billion. Multiple analysts estimated that the global market for contact lenses would reach $11.7 billion by 2015. , the average age of contact lens wearers globally was 31 years old, and two-thirds of wearers were female. People choose to wear contact lenses for many reasons. Aesthetics and cosmetics are the main motivating factors for people who want to avoid wearing glasses or to change the appearance of their eyes. Others wear contact lenses for functional or optical reasons. When compared with spectacles, contact lenses typically provide better peripheral vision, and do not collect moisture (from rain, snow, condensation etc.) or perspiration. This can make them preferable for sports and other outdoor activities.\n"}, {"role": "assistant", "content": "I have worn contact lenses for a long time due to near sightenness. They are lenses placed directly on the eye."}, {"role": "user", "content": "Oh!  Are they really helpful for your vision and better than glasses?"}, {"role": "assistant", "content": "They provide a clearer vision than glasses, especially with regards to peripheral vision."}, {"role": "user", "content": "That sounds like a great benefit!  Are the comfortable enough to not realize they are in your eyes?"}, {"role": "assistant", "content": "I believe so.  They work for a lot of people.  Over 125 million people worldwide wear them."}, {"role": "user", "content": "Wow!  I would never have guessed that many people wore them!  When were contacts invented?"}, {"role": "assistant", "content": "I really have no idea.  I do know I prefer them when I play sports or do outdoor activities."}, {"role": "user", "content": "Yeah, that sounds so much more convenient than having to wear glasses!  Are they expensive to use?"}, {"role": "assistant", "content": "Not as much as glasses.  Although glasses can protect from light and radiation better than contacts."}, {"role": "user", "content": "That is true.  I would imagine that overall they are more convenient and preferred though, right?"}]