Answer the following :
(a) What is the function of the lacrimal gland and where is it situated in the body?
(b) In what two ways is the yellow spot different from the blind spot?
(c) Name an old-age eye defect. What causes it?
(d) What is meant by power of accommodation of the eye?
(e) Mention the characteristics of the image that falls on the retina of the eye.
(a) The lacrimal gland is a tear gland located at the upper sideward portion of the eye orbit. Its secretion lubricates the surface of the eye, washes always the dust particles and kills germs
(b) Yellow spot is the region of brightest vision and contains maximum sensory cells whereas a blind spot contains no sensory cells and this is the point of no vision.
(c) Presbyopia is an age-old eye defect. In this condition, the lens loses flexibility resulting in far-sightedness. Cataract is also very common in old people, the cornea becomes opaque and the vision is cut down even to blindness.
(d) The process of focusing the eye by varying the curvature of the lens at different distances is called the power of accommodation.
(e) The image formed on the retina is inverted and real.