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Understanding How the Eye Works

The eye works like a camera.


Light rays enter the eye through the cornea, then travels through the lens where it is fine tuned to focus properly on the retina. Light is then changed by the retina into electric impulses that are carried by the optic nerve to the brain.


For you to see clearly, light must come to a focus precisely on the retina. If light cannot focus properly you will need glasses or contact lenses to help achieve that.



The cornea is like the window of the eye. It provides most of the focusing power when light enters the eye. The cornea is composed of 5 layers of tissue; the outer layer (epithelium) is the eye's protective layer. Most of the inner layers provide strength to the eye. The cornea has the ability to grow back every 3-7 days and therefore allow for fast healing of superficial injuries.



The pupil is the black circle in the center of the eye. The primary function of the pupil is to control the amount of light entering the eye. When you are in bright light, the pupil constricts to allow less light through. When it is dark, the pupil expands to allow more light to reach the back of the eye.



This is the coloured part of the eye (e.g. blue, green, brown, hazel). The iris controls the pupil size by contracting or expanding the muscles of the iris.



The lens is a natural lens of the eye. It is a transparent, biconvex structure located behind the pupil. Its main function is to fine tune the light for focusing and reading. The lens preforms this by altering its shape. At approximately age 40-50, the lens becomes less flexible and presbyopia sets in. At about the age of 60 or 70, the lens can become cloudy and harder. This indicates the beginning of cataracts which prevents the light from entering the eye.



The retina consists of fine nerve tissue which line the inside wall of the eye and act like the film in a camera. Its primary function is to transmit images to the brain. There are 12 layers that make up the retina.


Optic Nerve

The optic nerve carries images from the retina to the brain.



This is the white part of the eye. The main purpose of the sclera is to provide structure, strength and protection to the eye.



This is the clear, gel-like substance located inside the eye cavity behind the lens. Its main purpose is to provide a spherical shape to the eye. The vitreous sometimes may develop small clumps known as floaters which are more common in nearsighted people.


If you are concerned that something is wrong with your eyes, contact us immediately.

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