About the Eye

About the Eye

At Fraser Eye Care Center and the Eye Care Center of Port Huron, we believe in providing education to all patients. To understand how treatment will improve or correct vision, it is important to comprehend how the eye works, and how conditions and changes to the eye affect vision.

How does the eye work?

The human eye is made up of many parts, each having unique characteristics and responsibilities for the “seeing” process. These parts gather light, “refract” or bend light rays and process light energy into signals to allow the brain to interpret shapes, colors and dimensions of objects into the world around us. These parts of the eye including iris, pupil, cornea, lens, retina, fovea and optic nerve, all work in unison and are equally important in our vision.


  • Iris
  • The iris is the colored part of the eye that controls the amount of light that enters into the eye, like the shutter of a camera.

  • Pupil

    The pupil is the opening in the middle of the iris that allows light to pass through.

  • Cornea

    The cornea is the clear dome that covers the front of the eye and is responsible for most of the bending of light rays. The shape of the cornea typically remains constant through our lifetime.

  • Lens

    A lens resides inside the eye to help focus the light. This lens changes shape as our focal point moves from object to object.

  • Retina

    The retina is a thin layer of photosensitive tissue that lines at the back of the eye that receives the light and converts it into nerve signals.

  • Fovea

    The fovea is the center portion of the retina, where cells are more densely packed, so light can be processed with greater detail.

  • Optic Nerve

    The optic nerve carries nerve signals from the retina to the brain for interpretation.