The best way to measure your eyesight and health

For those who are new to eye exams, one of the most important measurements performed during your eye exam is the refraction measurement. Refraction refers to the bending of light as it passes from one transparent substance into another. For example, light waves are bent, or refracted, as they pass through the cornea and lens of your eye. The curve of the lens focuses the light onto the retina, or the back of the eye. The image is then captured by photoreceptors in the retina and sent to the brain to create the images you see. When it comes to eye exams, the refraction measurement determines if you need prescription lenses, as well as what prescription lens will give you the best possible vision.

The results of the test are used to diagnose the following conditions:

  • astigmatism, a refractive problem with the eye related to the shape of the lens, which causes blurry vision
  • hyperopia, which is also known as farsightedness
  • myopia, which is also known as nearsightedness
  • presbyopia, a condition related to aging that causes lens of the eye to have trouble focusing

The results of the test can also help diagnose the following conditions:

  • macular degeneration, a condition related to aging that affects your sharp central vision
  • retinal vessel occlusion, a condition that causes the small blood vessels near the retina to be blocked
  • retinitis pigmentosa, a rare genetic condition that damages the retina
  • retinal detachment, when the retina detaches from the rest of the eye