Vision Basics


Presbyopia is an unfamiliar word, but it is one of the most important concepts to understand when considering laser vision correction.

Presbyopia affects the near vision. In order for a person with clear distance vision to see up close, the ciliary muscles inside the eye must contract and cause the lens to change shape. In younger individuals, the lens is flexible and changes shape easily, so near objects come into focus. However, around 40 years of age, the lens hardens to the point that it no longer changes shape, and reading glasses are needed to provide a boost to the near vision.

Here is a summary of how presbyopia affects various individuals:

Most people over 40 whoNeed help to see up close with
Wear glassesBifocals (some can just remove their glasses)
Wear contact lensesReading glasses or bifocal contacts
Were born with and still have clear distance visionReading glasses
Have both eyes laser corrected for distanceReading glasses


After learning about presbyopia, the first question many over 40 ask is if there is any way to reduce the need for reading glasses after laser vision correction.

The answer is yes. There is an option known as monovision.

Monovision has been used for years in the fitting of contact lenses. The most common technique is to correct the dominant eye for distance vision and the leave the non-dominant eye somewhat blurry at distance, but better up close.

Monovision is a compromise. The distance vision isn’t quite as good as it could be, because one eye is doing most of the work, and the near vision isn’t perfect for the same reason. However, for many, the brain is able to fill-in the gaps and everything seems clear.

For patients over 40 who are interested in monovision, most surgeons will recommend a first-hand experience of what it is like, most commonly through in-office trial lenses or take-home contact lenses, prior to laser vision correction. As much as the benefits may sound appealing, there is no substitute for actually looking through monovision lenses, as some patients don’t tolerate the inherent imbalance as well as might be hoped.

Presbyopia and monovision are extremely important topics to understand. With current laser technology circa 2006, patients over 40 have only two realistic options. The first is to have both eyes fully corrected for distance and wear reading glasses for up close. The other is to have monovision.

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