Something that causes a response in a body part or organism. A stimulus may be internal or external. Sense organs, such as the ear, and sensory receptors, such as those in the skin, are sensitive to external stimuli such as sound and touch.
Just curious...given my insurance plan I can get a new pair of frames and lenses once every 2 years, but I realllly love glasses so I tend to purchase about 2 pair per year...Gotta have my style...oh and of course the added benefit of sight is a nice plus:)
Then, you may wear four hours on the second day. By parity of reasoning, you just add two hours every day to wear contact lenses until the fifth day. However, after you have adapted to wearing it, you should keep in mind that not wearing contact lenses more than 8 hours every day.