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Eyes And Vision

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by

Lulii Salman

on 21 April 2014

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Transcript of Eyes And Vision

Eyes And Vision
Structure Of The Eye
Light enters the eye passing through the cornea and the pupil
The iris, controls the amount of light entering the eye.
- It closes when light is bright allowing less light to enter the pupil
- It opens when light is dim allowing more light to enter the pupil.
Ciliary muscles surround the lens. The muscles hold the lens in place .
-When the muscles relax, they pull on and flatten the lens, allowing the eye to see objects that are far away.
-When the muscle must contract, they thicken and shorten the lens, allowing the eye to see objects that are nearby.
after that, light passes through vitreous humor, striking the retina.
When light strikes the rods and the cones of the retina, it's converted into an electric signal that is relayed to the brain via the optic nerve. The brain then translates the electrical signals into the images we see.
Vision Problems
Vision Correction Surgery
Laser eye surgery is a treatment for vision problems, such as myopia, hyperopia, and astigmatism, that eliminates the need for eyeglasses or contact lenses.
There are two types of laser eye surgery:
LASIK
PRK
PRK
Photorefractive keratectomy or PRK is a type or laser eye surgery uses to correct Myopia, Hyperopia, or Astigmatism, it works by reshaping the cornea so that light traveling through it is probably focused on to the retina
Risks:
eye infection
ectasia
dry eye
Advantages:
highly affective
Disadvantages:
mild discomfort
longer recovery time
LASIK
laser assisted-in-situ keratomileusis or LASIK is preformed by a doctor to correct Myopia, Hyperopia, or Astigmatism. the surgeon creates a thin flap in the cornea to access the treatment area. LASIK is a minor surgery but still has its risks, advantages, and disadvantages.
Risks:
you maybe over-corrected or under-corrected
you may still need glasses or contact lenses to achieve your vision
your results may not be permanent
dry eye symptoms may occur or get worse
you may lose vision.
advantages:
takes less than 30 mins. or less to preform and is ever effective
disadvantages:
it is done on a very sensitive part of the eye and is not reversible
so the lens focuses the image in front of the retina instead of on the retina, which results blurred far objects.
Is when the eyeball is too long
To correct this you use a concave lens
is when the eyeball is too short
so the lens focuses the image behind the retina instead of on the retina which results blurred near objects
to correct that you use convex lens
Nearsightedness/Mypoia
Farsightedness/Hyperopia:

Common Diseases
Cataracts:
A cataract is a clouding of the normally clear lens of your eye.

Symptoms:

Cloudy, blurry dim vision
More difficulty seeing at night or in low light
Seeing halos around lights
Faded or yellowed colors
The need for brighter light to do activities
Double vision within one eye

Causes:
Aging, trauma, radiation, genetic, & drug use.

Treatment:
Cataract surgery.

Astigmatism
It is caused due to irregular shape of the cornea which is steeper in one direction
and causes blurred vision
Retinal Detachment:
Is a disorder in which the retina peels away from the supporting tissues underneath it.


Risk factors:
Family history of retinal detachment.
Severe Myopia
Retinal tears
Cataract surgery

Symptoms:
Flashes of light
Dramatic increase of floaters
A shadow that starts from the periphery and progresses towards the center.

Treatment
:
Vitrectomy.
Scleral buckle surgery.
Gas bubble.
Silicon oil.
Done by:
Lulu Saedan, Maryam Radwan,
Banan Al-Batati, Nora Buhairi,
Almaha Aldhelaan, Sadeem AlHarbi,
& Dania Najm
Grade:
9/1
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