Question

collect information about different types of eye defects from your nearest eye specialist or optical shop and write a report

Answer 1

eye defects : these are usually the result of weak muscles in the eye.

1) Myopia or short sight
2) Long sightedness
3) astigmatism  - distortion along different axes
4) color blindness

Contact lenses or spectacles with lenses are used to correct them.  They are plano convex lens, biconvex lens, plano concave lens, biconcave lens, lens with a combination of convex & concave surfaces.

Cylindrical lenses are used to correct astigmatism.