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Get key facts and figures about chronic dry eye

Understanding your Vision


Vision is the ability to see. To have vision, you need light, and the use of your eyes and brain. The eye is made of different parts that work together.
  • The outside clear layer in the front of your eye is the cornea. Around the cornea is the white part called the sclera. Light rays enter your eye through the cornea as they bounce off the object you are looking at. The light then passes through the pupil, which is the black circle in the middle of the iris. The iris is the colored part of your eye. This controls how much light is needed as it goes into the eye for you to see well. The iris closes the pupil in bright light and opens it when the light is dim.
  • Behind the iris is a clear lens that changes shape as you look at objects at different distances. Light goes through this lens on its way to the retina at the back of the eye. The retina is a special layer of nerves on the back inside wall of your eyeball. The retina turns the light rays into images or pictures and sends them to the brain as impulses (signals). The brain combines the images that each eye sees to make one picture. It also helps you understand what you are seeing.


Eye checks:

You should have a complete eye exam regularly. This includes tests that may help learn about your vision and check for signs of eye problems.

  • Have your eyes checked at least every few years until you are 40 years of age, then every 2 to 3 years thereafter.
  • Have your eyes checked more often if you are at risk of having eye problems. Risk factors may include having diabetes or hypertension (high blood pressure).
  • Ask your caregiver for more information about eye checks.

First aid for eye injuries:

The following are first aid treatments for some of the common eye injuries. Make sure to have a caregiver check your eye. Any eye injury may be more serious than what it seems.

  • Blows: If your eye gets hit, apply cold cloths on your eye for 15 minutes. This will help decrease swelling, pain, and redness around your eye.
  • Cuts or punctures: If an object gets stuck in your eye, do not pull it out or try to remove it. Put a loose bandage on your eye and seek care immediately.
  • Chemical burns: If a chemical gets into your eye, wash it out with water for at least 10 minutes. Chemicals may include cleaning fluid. Have your caregiver check your eye right away.
  • Foreign object: Wash your eye with water if sand, dust, or other foreign objects get into your eye. Do not rub your eye.

Preventing eye injuries:

  • Always wear safety glasses, eye shields, or goggles when working with power tools, gardening, or playing sports.
  • Do not rub your eyes while working with wood or metal pieces.
  • The correct use of contact lenses is very important. Know when and how long they can be used, and how to clean and store them properly.


  • You have trouble seeing even when using corrective lenses.
  • Your eye problem prevents you from doing your daily activities.
  • You have discharge or pain from your eye.
  • You have questions or concerns about your eye, condition, medicine, or care.


  • You develop blurred vision or blind spots.
  • You suddenly lose your eyesight.
  • You feel a sudden, sharp pain in your eye.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.