How do we see using intraocular lenses (IOLs)?

For us to see clearly, light rays enter our eyes through the clear cornea, pupil and lens. These light rays are focused directly onto the retina, the light-sensitive tissue lining the back of our eyes.

The retina converts light rays into impulses that are sent through the optic nerve to our brain, where they are recognized as images. Seventy percent of the eye’s focusing power comes from the cornea and 30 percent from the lens. While problems with the cornea (the clear front window of your eye) or the lens may prevent light from focusing properly on the retina, a refractive error may prevent us from seeing clearly in certain situations, despite having a clear cornea and lens.

Today, many people are choosing to correct their refractive errors with options other than eyeglasses or contacts.

Various forms of refractive surgery — such as LASIK — improve vision by permanently changing the shape of the cornea to redirect how light is focused onto the retina. In some cases, instead of reshaping the cornea, the eye’s natural lens is either replaced or enhanced by an implanted intraocular lens (IOL) that helps correct vision.

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