Monovision Contact Lens Information
By the time we reach our mid-forties, most of us have lost the ability to focus up close. This condition is called presbyopia (Greek for "old man eyes"). There are several treatment options available, including bifocal eyeglasses and bifocal contacts. A lesser known, and more exotic sounding, treatment option is monovision contact lens fitting. This is how it works.
Other People Are Reading
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It Starts With the Brain
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The brain is constantly receiving separate and unique images from each eye. Think of the eyes as two video cameras independently feeding images to a central production studio.
Eye Dominance
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Just as we are right or left handed, we are also right or left eyed. The dominant eye passes the image to the brain 14 to 21 milliseconds faster and thereby becomes the main point of reference for our vision.
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Monovision Contact Lens Fit
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The dominant eye will do the majority of the work, so the doctors fits it with a contact lens to correct distance vision. The non dominant eye, which normally would have only provided depth perception, is now fit with a contact lens for near (reading) vision.
Back to the Studio
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The brain is now receiving two very different images. One is clear at distance and blurry up close while the other is clear up close and blurry at distance. The brain, like a television director, seamlessly switches to whichever "camera" suits it's present need.
Monovision Is Not for Everyone
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While monovision represents a good compromise between distance and near vision, it typically does not deliver "best possible" clarity at either distance. There is also a drop-off in depth perception and peripheral vision.
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References
Resources
- Photo Credit Image by Flickr.com, courtesy of Logan Ingalls
