Difference between convex lens and concave lens in tabular form
Difference between the convex lens and the concave lens
CONVEX LENS  CONCAVE LENS 
Definition  
A convex lens Is a piece of transparent material which is thick at the Centre and thin at the edges  A concave lens is a piece of transparent material which is thin at the Centre and thick at the edges. 
Nature  
Convex lenses are called converging lenses because they converge the light.
 Concave lenses are called diverging lenses because they diverge the light.

Focal length  
Its focal length is positive.  Its focal length is negative. 
Use  
It is used for the Correction of Longsightedness.  It is used for the correction of shortsightedness.

CONVEX LENS
It is a lens which is thick at the Centre and thin at the edges. It converges a parallel beam of light at a point and hence is called a converging lens.
TYPES OF CONVEX LENS
(a) Double Convex Lens
Both the surfaces of a double convex lens are convex.
(b) Plano Convex Lens
One of the two surfaces of such a lens is plane and the other is convex.
TYPES OF CONCAVE LENS
(a) Double Concave Lens
Both the surfaces of a double concave lens are concave.
(b) Plano Concave Lens
One of the two surfaces of such a lens is plane and the other is concave.
(c) ConvexConcave Lens
One of the two surfaces of such a lens is concave and other is convex.