Eye Health Matters > Vision Correction -Nearsightedness

Nearsightedness, or myopia refers to vision that is good at close range but poor at a distance. Nearsightedness generally occurs because the eyeball is too long as measured from front to back - being oval-shaped instead of being spherical. This causes the eye's overall power to be too strong.

Because of the increased distance between the cornea and retina, light converges in front of the retina, rather than on it, making distant objects blurry. A nearsighted person will often squint in order to see distant objects-utilizing the pinhole effect.

Nearsightedness is the most common vision problem in the U.S. affecting about 50 percent of the population. It usually develops in children and teenagers during growth periods, and may require frequent changes in corrective lens prescriptions - another reason why regular eye exams are important. It usually stops progressing around age 20, when growth is completed.

Most experts believe that nearsightedness is genetic. However, it is difficult to ignore (and study) the effects of intense close-vision activities such as reading or computer use and it's relationship to the development of nearsightedness.

Symptoms

People who are nearsighted have blurred vision or difficulty focusing on distance objects such as road signs or a movie screen, but can focus well with close objects such as reading a newspaper or road map. Poor school performance is often the first clue in children, since they cannot see the blackboard. Other symptoms can include:

• Squinting to focus in the distance
• Eye strain
• Headaches from squinting or eye strain.
  
  

Most cases of nearsightedness are inherited, and therefore cannot be prevented. However, its severity may be affected by poor nutrition, stress and intense close visual work under poor lighting or too much glare. When performing close visual work, keep the work area well-lit and glare-free, and take breaks every 30 minutes or so from close visual activity, and focus on distant objects to give your eyes a break.