Introduction
The eye is the window to the world. Through our eyes, we can see the things around us and perceive
sensory stimulation. However, the eye is not merely a sensory organ that helps us receive visual
stimulation. Anatomically, the eye consists of the conjunctiva, cornea, iris, pupil, lens, retina, blood
vessels and optic nerve. Pupil is the part of the eye that is responsible in controlling the amount of
light that comes in through the eye to the retina. Light adaptation is a considered as an important
function for too much light can blind the eye, while too dim will result in the inability to
see.(Sherwood, 2007)
The pupil responds to light in two ways: dilate or constrict. In a bright area, the pupil will constrict to
limit the amount of light. In contrary, pupil dilation will occur in dim area. Both the dilation
(mydriasis) and constriction (miosis) of the pupil happens without awareness. Pupillary response is
controlled by the autonomic nervous system. (Fion Bremner, 2009)
Success in public health programs, better education and advancement in medicine has led to higher
life expectancy. WHO released the list of countries with the highest life expectancy by gender groups.
(“WHO | World Heal F