JAMB - Biology (2000 - No. 18)
Short-sightedness can be corrected by lenses which are
convex
biconvex
plano-convex
concave
Paliwanag
Concave lenses, also known as minus lenses, are used to correct short-sightedness, or myopia:
Concave lenses work by bending light rays outwards, which causes them to focus further back in the eye on the retina. This counteracts the tendency of short-sighted people to focus before the back of the eyeball.