Sunday, August 19, 2012

How can Plus lenses correct distance vision?

I am studying to be an optician.In my text book it states that Plus lenses are used to correct Hyperopia or farsightedness, and minus lenses are used to correct Myopia or nearsightedness. This all makes sense to me for the most part. What confuses me is how many plus lenses I dispense on a weekly basis that are used to correct distance vision. If plus lenses are only for farsightedness correction, the how come all these people use plus lenses for distance correction as well?

Or are the terms "nearsightedness" and "farsightedness" used not to describe what the person is capable of seeing, but rather for example "farsightedness" is a condition where the light goes too far and passes the retina? Is that what these terms are supposed to mean? I assume not - I just am very confused. I personally have a plus lens in one eye and a minus in the other. Both help me with distance and both are not incredibly strong - so i know that obviously both are possible. But based on what the book says only farsighted people use plus lenses & its definitely not 'near vision' I have a problem with.
>>> How can Plus lenses correct distance vision?