Myopia or Near-sightedness

Due to myopia the eyes are able to see nearby objects clearly but cannot see the distant objects clearly. This defect is caused due to the formation of image of distant object in front of the retina.     Cause of Myopia An eye suffers from the defect of myopia...

Common defects in human eye

Human eye is very sensitive organ of the body. It is essential for every individual to take full care for keeping human eye healthy. There are many types of defects that develop in human eye. Following are the common defects found in a human eye: Myopia or...

How do we see colours

Retina contains a large number of light sensitive cells called rod cells and cone cells. The rod cells respond only to the intensity of light, while the cone cells respond to the colours of an object. There are 3 types of cone cells which are sensitive to red, blue...

Light and dark adaptation in human eye

We have already studied that the amount of light entering the eye through pupil is controlled by iris. But this adjustment takes some time. For example, our eyes cannot see everything clearly when we enter a dark room from a bright light. The reason for this is that...

The human eye

The human eye is one of the most important and sensitive sense organ gifted to us by the God. The construction and working of the human eye is like a camera forming an inverted and real image. The diagram showing the structure of human eye are sclerotic, cornea,...

Optical Instruments

The optical instruments are the devices which help us in seeing objects. The most common examples of optical instruments are our eyes, microscope, and telescope. These instruments contain lenses and form images by refraction of light through lenses. In this chapter we...