All About The Different Parts Of The Eye: Cornea, Iris, And Lid

Learn about the different parts of the eye and how they work. Tips about cleaning and common vision problems.

Touch, smell, and taste, hearing and sight; these of coarse are the gift of the "five senses".The loss of one of these senses may make our daily activities a little more challenging or unpleasant than one who retains them all.One sense that has always fascinated me is the gift of sight.Imagine losing that gift; not being able to see the changing colors of the trees during the fall season, seeing the first blanket of snow as it shimmers in the sunlight, or watching your child grow and change throughout the years. Imagine being able to transplant this organ into another human being so that the may be able to one day, see.What is this organ called the eye?

The Cornea and its function

The cornea is the clear tissue that covers the front of the eye.If you look closely at your eye in the mirror, you will be able to see a clear covering over your Iris (the colored part of your eye); this is the cornea.The cornea protects the inside of your eye from germs, dust and any other harmful matter; however, the cornea is susceptible to injury and infection.

The cornea is the eyes' outermost lens.When light hits the cornea, it refracts the light onto the crystalline lens, which focuses the light onto the retina.The retina than translates the light, sending a signal through the optic nerve to the brain, which becomes vision.

How does the Cornea affect vision?

The cornea is very important to having good vision.The cornea filters out some of the damaging UV rays and with out this protection, the retina could be damaged.The cause of having nearsighted vision is from the cornea being too curved, making the light refract imperfectly on the retina thereby making far away objects blurry.If the cornea has imperfections, the light will refract unequally, causing a slight distortion of a visual image. This is what we call astigmatism.If the cornea has no imperfections, the light refracts into the retina equally thereby causing no vision irregularities.

The Iris and its function

The Iris is the colored portion of your eye and is made up of muscles that change the size of your pupil (the black center of your eye).The changing of the size of your pupil helps to regulate the light entering the eye.The Iris of the eyes is like a snowflake; no two are alike, not even among twins.

How does the Iris get its color?

The Iris of the eye is made up of cells (the stroma) that contain a brown pigment called melanin, which reflect brown light.If the stroma of the Iris contains little of this pigment, the Iris reflects more of the blue light, causing the blue light to scatter out of the eye.When a person is looking at you, what they see is the out going blue light, which perceives the Iris to be blue.Blue eyes are blue for the same reason the sky is blue.When a baby is born their eyes are blue because the melanin in their Iris has not yet browned.If no melanin is present within the stroma, the Iris turns red, like in an Albinos' eyes.

The Eye Lid

The eyelid is the thin layer of skin that covers your eye and protects your eye from harmful substance.Consider this layer of skin to be the "windshield wipers" for your eyes.Every time you blink the lid sweeps the dust and debris from the cover of your eye, helping to protect the eye from infection.The eyelid also lubricates the eye and helps to drain away tears.

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