Which of the following is true with regards to the eye?

Which of the following is true with regards to the eye?

a. Cone cells in the retina detect color in bright light.

b. Cone cells in the retina detect shades of grey in dim light.

c. Rod cells in the retina detect color in bright light.

d. The cornea is made of dense connective tissue.

e. The lens has a rich blood supply.

Answer: The correct options are a and d.

The retina contains two types of photoreceptor cells: The photoreceptors in the retina are of two categories namely rods and cones. Cone cells are the cells that are used in color perception and are most effective when exposed to high amounts of light. These are situated in the fovea centralis which is a part of the retina that is used in high visual resolution. While rod cells are able to function better in the dark and only respond to one type of colour, namely black and white.

The cornea is the anterior transparent part of the eye which is composed of connective tissue. It does not contain a blood supply and nourishment is received through the tear film and the aqueous humour. The lens which is found at the back of the pupil is also avascular and is nourished by fluids that surround it.