This is because our eyes produce less oil once we age and so the ability to retain the on the eyes is significantly less proficient so water is lost quicker pc is supplanted.
Artificial tears are made of a solution that is analogous to that of a natural tear. http://low.gs/__media__/js/netsoltrademark.php?d=Www.Drbigboobs.com%2Fcgi-bin%2Fat3%2Fout.cgi%3Fid%3D25%26trade%3Dhttps%3A%2F%2FPenzu.com%2Fp%2F2e0ad6fe46f21166