Why do people wear long distance glasses?

Distances - as opposed to reading etc.

There are three main reasons people need glasses for distance vision.

Primarily Myopia (shortsightedness)is the cause for most people and this is because optically light converges not on the retina but falls short therefore a concave lens is required to placed in front of the eye in order to obtain the clear image.

Astigmatism is where vision is best described as skewed owing to the shape of the eyeball this condition affects both near and distance vision and can be very tiresome.

Finally hyperopia- (longsightedness) is NOT as many people believe "simply the opposite of myopia(shortsightedness) Hyperopia is opposite only in the respect that the rays of light are focused behind the eye and a convex lens facilitates this.

More often than not people with hyperopia have more difficulty with near objects, but depending on the amount of hyperopia and their age (if over 45 or so) they could well require the convex lenses to see at distance.