Match the following.

Diseases / Defects	Causes
1) Glaucoma	A) Infection in one of the layers of the eye
2) Conjunctivitis	B) Defects of the cone cells
3) Colour Blindness	C) The lens of the eyes become opaque
4) Cataract	D) Accumulation of aqueous humour

The correct option is A

1 - D, 2 - A, 3 - B, 4 - C

Conjunctivitis is a disease caused due to infection in the conjunctiva. It may be caused by any pathogen spread through contact. Glaucoma is a condition in which the aqueous humour isn't reabsorbed and gets accumulated in the eye. It causes an increase in pressure within the eye leading to blindness eventually. Colour blindness is a condition in which the ability to distinguish between colours is lost. It is mainly due to a defect in photoreceptors known as cones. Cataract is a condition in which the lens of the eyes becomes cloudy, impairing vision. It can be corrected by replacing the lens with artificial ones through surgery.