Which spectacle lens fixes short-sightedness, and which fixes long-sightedness?
A short-sighted (myopic) eye focuses images in front of the retina, so it needs a concave (diverging) lens to spread the rays out before they enter the eye.
A short-sighted (myopic) eye focuses images in front of the retina, so it needs a concave (diverging) lens to spread the rays out before they enter the eye. A long-sighted (hypermetropic) eye focuses behind the retina, so it needs a convex (converging) lens to bring the focus forward. Remember: myopia → concave (minus power), hypermetropia → convex (plus power).
Key point
Myopia → concave lens; hypermetropia → convex lens.
Common mistake
swapping the two corrections.
Memory tip
'minus for myopia' — concave for short sight.
Tap to watch or see it right here — the app stays open (it only opens a quick search if nothing embeddable is found).