The Eye is the organ of sight. Eyes enable people to perform daily tasks and to learn about the world that surrounds them. Sight, or vision, is a rapidly occurring process that involves continuous interaction between the eye, the nervous system, and the brain. When someone looks at an object, what he/she is really seeing is the light that the object reflects, or gives off. This reflected light passes through the lens and falls on to the retina of the eye. Here, the light induces nerve impulses that travel through the optic nerve to the brain, where it makes an...
vision. Prismatic lenses are prescribed to correct this defect.

Imperfections in the cones of the retina, resulting from heredity or disease, cause defective color vision. This is known as color blindness, or Daltonism. In total color blindness, everything appears in shades of gray. In its more common from, color blindness is the inability to distinguish between reds and greens.

Persistent headaches, blurred vision, and painful inflammation of the eyelids are symptoms that may indicate serious eye disorders. Particles lodged in the eye should be removed without delay. Glasses are prescribed to strengthen vision and to reduce strain and fatigue.