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:)
Prescription Reading Glasses vs OTC. Typically, about the time you hit 40, though sometimes a bit earlier or later, you start to need reading glasses for up close work. People who do a lot of fine detailed work or work with numbers, like seamstresses and accountants, may notice the need earlier, but eventually it happens to almost everyone.