The Eye’s Lens and Cataract Surgery

A cataract cannot be removed from the eye’s lens. Therefore the only way to treat cataracts and restore your vision is to remove the entire lens and replace it with an artificial lens called an intraocular lens (IOL). The IOL is positioned inside the same pocket that the natural lens previously occupied.

In past years, IOLs were monofocal. That is, they gave clear vision for close, intermediate, or far distances, but not all three. A person chose which distance range they wanted corrected with IOLs and then wore glasses to correct for the other distances. Alternatively, they could have one eye corrected for near vision and the other for distance vision. Then the brain learned how to interpret those two sets of data so that you could see clearly at both distances.

Now there are several IOLs that give clear vision at all distances, and another one currently in testing for FDA approval.

The Lens and Accommodation

When the natural lens is removed from the eye, accommodative ability is also lost. In a normal eye, the lens changes its curvature according to how far away an object is. A circular muscle (the ciliary muscle) is attached to the entire lens periphery and controls lens curvature:

  • When this muscle relaxes, the lens curvature becomes steeper. This gives clear near vision.
  • When the ciliary muscle contracts, the lens flattens out, and you have clear distant vision.

We do not feel this happening, or will it to happen. It happens automatically when you switch your focus from near to far and back again. For more information please see How the Eyes Work.

Modern IOLs

To somehow replace this accommodative ability, lens manufacturing companies have done a great deal of research and testing and each company has devised a different way of solving the problem. They all use different technologies and you can read more on our IOL Technology page and on the Crystalens® page.

Now when cataract surgery is done, the natural lens is replaced with one of these newer IOLs instead of a monofocal IOL. This makes for far more patient satisfaction.

Please contact us today if you would like to speak with a qualified ophthalmologist in your area.