How Your Eyes Work

Blurry vision can be attributed to several causes, and they stem from how the eye works and how it has developed. The eye is a tiny organ that measures about an inch long and weighs about 1/4 of an ounce. It is part of a complex system that translates light into images. Light enters your eye through the cornea and into the pupil. The pupil is the black hole in the middle of the iris, which is the colored part of the eye. Behind the iris is the eye’s natural lens. It focuses the light onto the retina. The retina is the inside layer at the back of the eye, and contains cells that are sensitive to light. The image is then converted into electrical impulses that are sent through the optic nerve at the back of the eye to the brain.

All of this happens continuously and instantly to give you clear vision from near to far distances. But eyes don’t always work perfectly. Their exact size and shape affect how well they focus light. These differences can cause some people to have refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), or astigmatism. In addition, over time, everyone loses the ability to focus on near objects. This is a refractive condition known as presbyopia, or blurry near vision, and is the first stage or dysfunctional lens syndrome (DLS). If uncorrected, DLS will progress. DLS stage 3 is a cataract.

Myopia (Nearsightedness)

  • myopiaNear objects are clear, but objects at a distance are blurry
  • It is hard to focus on an object or detail far away, or across the room
  • Occurs when the cornea (front surface of the eye) is too rounded or steep, or the eyeball is too long

Hyperopia (Farsightedness)

  • hyperopiaObjects at a distance are clear, but objects up close are blurry
  • Occurs when the cornea is too flat or the eye is too short
  • Hyperopia, or farsightedness, differs from presbyopia in that hyperopia is caused by an irregularly shaped eye that prevents light from properly lining up on the retina, and is not necessarily an age-related condition


  • astigmatismLight coming into the eye is focused inconsistently
  • All objects are stretched or distorted
  • Occurs when the cornea has an irregular oval shape
  • Can occur simultaneously with nearsightedness or farsightedness

Dysfunctional Lens Syndrome (DLS) Stage 1 – Presbyopia

  • presbyopiaPresbyopia, or DLS stage 1, is the clinical term for near vision loss that starts affecting you in your 40s and 50s
  • Over time, the eye’s natural lens becomes too stiff to effectively focus up close
  • Print and other nearby objects become blurry

Dysfunctional Lens Syndrome (DLS) Stage 2

  • DLS stage 2 is the clinical term for near vision loss that typically starts affecting you in your 50s
  • The eye’s natural lens is continuing to yellow, which reduces the clarity of both distance and near vision

Dysfunctional Lens Syndrome (DLS) Stage 3

  • DLS stage 3 is the clinical term for cataracts, which typically starts affecting you in your 60s and on
  • The eye’s natural lens has become cloudy enough that it is significantly affecting your vision
  • Treatment is necessary to restore the quality of your sight