Understanding Your Eyes
Understanding Your EyesProject by: Jena Mahoney
Parts of the Eye
Pupil- the round black dot in the middle of your eyeIris- the colored part of your eye that is around the black dotCornea- a clear bubble that covers the iris and pupilAqueous Humor- clear fluid inside of the corneaLens- an oval shaped body behind the pupil and irisSuspensory Ligament- little strings that are pulled tight to hold the lens in placeCiliary Body- at the ends of the strings, produces aqueous humorVitreous Humor- clear jelly that fills your eyeSclera- the outer protective coat of your eye, the white stuffChoroid- layers of blood vessels underneath the sclera
Parts of Your Eye (continued)Retina- the sensory membrane underneath the blood vessels Fovea- a dip in the retina that only contains conesOptic Nerve- a cord at the back of your eye that is a messenger for your brainCentral Artery- a blood vessel inside the eye that is solely for nutritionVein of the Retina- forms with the central artery to drain the retinaOptic Disc- a circle at the back of your eye that the optic nerve attaches to the retina through
How Your Eyes Work (Our own personal camera)
Once the light hits these rods and cones on the retina (the sensory membrane) the image appears upside down.The optic nerve carries this image to the visual part of the brain, and it puts together the image. This all happens in 13 milliseconds!Light enters the eye through the cornea. (That clear bubble in front of the black dot and colored circle.)The black dot, the pupil, is actually a hole that opens and closes to allow certain amounts of light in the eye.After the light enters the eye, it passes through the hole. (The amount is regulated by the colored part of your eye.)The light then hits the lens and projects the light image onto the retina, which is full of thousands of rods and cones.
Things That Can Go WrongAmblyopia (lazy eye)- a vision development that causes the optic nerve to not pick up vision as well, could cause permanent vision loss.Astigmatism- caused by an irregular cornea, causes blurred vision at all distances.Color blindness- light sensitive cells in the retina fail to respond appropriately to variations in wavelengths of light, usually only affects males.Dry eye syndrome- the lacrimal gland doesnt produce enough tears, or not enough oil being produced causes excess evaporation of tears.Hyperopia (Farsightedness)- light rays entering the eye focus behind the retina, rather than on it, your eye is shorter than the average person, images are hard to see if closer up.Myopia (Nearsightedness)- light entering the eye does not focus properly on the retina, your eye is elongated, and objects are hard to see from farther away.
Why People Need Glasses
If you are nearsighted, farsighted or have astigmatism, you are in luck because it can be corrected easily with glasses! For nearsightedness, the lens on the glasses bend the light rays outwards to normalize the eyeball due to its extended length.For farsightedness, the lens on the glasses bend the light rays inwards before it reaches the lens of the eye, fixing the shortness of your eye.For astigmatism, you use bifocals, which bend the light both inwards and outwards, depending on the angle that you look in to them.Having glasses is normal and not geeky at all, many famous people wear them, (Justin Timberlake, Harry Potter, Johnny Depp & many more), along with 75% of the whole population!
Hopefully now you understand your eyes a little bit better now, so dont get discouraged if your eye doctor tells you that you have eye problems, they are perfectly normal and most of the time can be corrected!