|
|
 |
|
|
 |
|
 |
 |
Reading glasses, Bifocals, Presbyopia, and Monovision |
 |
|
|
|
|
As people age, their eyes gradually loses the ability to change focus from the distance to near. This loss of "accommodation" is called presbyopia and comes from a loss of flexibility of the lens inside the eye as well as some weakening of the focusing muscles inside the eye. Although this is a gradual change throughout life, it usually is not noticeable until the mid-forties. Although we may call this "reading vision", it is the near vision that we use for eating, putting on make-up, looking at our watch or similar tasks.
With the onset of presbyopia, typically between 40 and 45 years of age, some form of reading correction, such as readers, bifocals, or progressives, is required by everyone. A nearsighted person over age 40 who is also presbyopic, often uses their nearsightedness to see up close by removing their glasses or contact lenses, instead of using bifocals or readers. Through laser eye surgery, nearsightedness can be eliminated, so that the natural focus of the eye is adjusted for clear distance vision without glasses. Like any individual over the age of 40 who is not nearsighted, near vision tasks will require reading glasses. After laser eye surgery, it is as if you are always wearing your distance glasses or contact lenses and can't take them off to read. If both eyes are corrected for distance, reading glasses will be necessary in the presbyopic age group for near vision tasks.
To decrease the need for reading glasses, the technique of creating monovision may be helpful. Monovision is a technique in which the laser (or contact lenses) fully corrects one eye for distance, usually the dominant eye. The surgery on the other, usually non-dominant eye, is then planned to undercorrect. This leaves one slightly nearsighted eye that has reading vision without glasses. Monovision lets one maintain reading vision in one eye, to help avoid total dependence on reading glasses. As always, one must give up a little distance sharpness to gain the near vision. A weak distance lens may be needed at times for the slightly nearsighted reading eye for driving at night. Reading glasses will also still be needed at times for extended or difficult reading. Also, some depth perception may be lost, so it is generally not recommended for avid golfers, tennis players and others who place great importance on sports performance. Monovision does not eliminate, but can significantly reduce, the need for reading glasses. Most presbyopic patients find it to be a tremendous convenience not to have to constantly reach for reading glasses.
While we do not recommend monovision for patients under the age of 40, we do recommend that presbyopic patients consider a slight monovision correction. However, it is best to evaluate its suitability for your situation in contact lenses with your eye doctor before having laser eye surgery. Monovision can initially cause some mild discomfort such as eye strain or disorientation, and can take several weeks to get accustomed to. Monovision is reversible, and additional laser treatment can usually bring that eye to full distance correction.
During your consultation you can discuss this option with us, and together we can evaluate the best option for you.
|
|
|
|
|
|
|
|
|
|
|
|
