The Eye

How the Eye Works

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Crystalline Lens
Iris
Pupil
Cornea
Ciliary Body


Introduction to the Eye
Vitreous Body
Optic Nerve
Macula
Retina


The eye is like a camera in the way it captures and focuses the light. Here is the step-by-step of how the eye works to provide you with vision:

  1. Light enters the eye through the cornea, the clear, dome-shaped surface that covers the front of the eye.
  2. From the cornea, the light passes through the pupil. The amount of light passing through is regulated by the iris, or the colored part of your eye.
  3. From there, the light then hits the lens, the transparent structure inside the eye, which focuses light rays onto the retina.
  4. Finally, it reaches the retina, the light-sensitive nerve layer that lines the back of the eye, where the image appears inverted.
  5. The optic nerve carries signals of light, dark, and colors to the area of the brain (the visual cortex), which assembles the signals into images (our vision).

Normal Refraction

With normal vision, the cornea and the lens focus light directly onto the retina. Light rays entering the eye are focused sharply on the retina and the image you see is clear.

Eye anatomy

Refractive Error

Any change from this normal focusing is called a refractive error. Common types of refractive errors include myopia (nearsightedness), hyperopia (farsightedness) and astigmatism.

In all of these conditions, the person needs some type of corrective lens, such as glasses or contact lenses, to focus the light properly. LASIK and PRK laser eye surgery can change the shape and curve of the cornea to correct or reduce these types of refractive errors.

What is 20/20 vision?

20/20 is a measurement of your distance vision. 20/20 vision is frequently described as a person being able to see detail from 20 feet away that a person with normal vision can see from 20 feet. Therefore, if a person has a 20/40 vision, this indicates that the person would have to be 20 feet away to be able to see what a person with normal vision of 20/20 could see at 40 feet.

Find out what kind of results you can expect from laser vision correction at LASIK MD.

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