Monovision – Presbyopia Treatment
If you have normal distance vision (either with or without lenses, or after refractive surgery), as you reach 42 to 45 years of age, presbyopia develops. There are no exceptions to this rule. Presbyopia is the loss of ability to accommodate. Accommodation is the ability to focus up close. Each year it gets worse. If you are presbyopic, you either need bifocals or a separate pair of reading glasses to see what you normally could see up close when you were younger. By the time you are 60 you will have lost essentially all of your ability to focus closer than 3 feet. So, all close objects will be blurred.
The use of one eye for distance vision and one eye for near vision is referred to as monovision and is one of the options to consider as part of your refractive surgery decision. This is primarily applicable to those 40 years and older. Monovision has been used successfully for many decades with contact lens correction and with various types of refractive and cataract surgery. By correcting one eye to focus in the distance and one eye to focus for near, the vision part of our brain tends to suppress or filter out the image from the eye that is not in clear focus. The patient is not bothered by the eye that is not in focus. We create monovision using the laser such that the dominant eye focuses at distance and the non-dominant eye at near.
One of the best ways to define monovision in the context of refractive surgery is that you can aim to have each eye corrected to a natural focus at any distance you choose. How well it will see at other distances depends upon how old you are. For example, if you are 30 and we correct each eye to excellent distance vision, then you will have good vision at almost any distance because, due to your young age, the eye will be able to accommodate (adjust focus) from far to near. If, on the other hand, you are over 40 and we correct each eye to excellent distance vision, you will not see well at a typical reading distance and will need reading or near vision glasses. This change in accommodation (focusing ability) will generally begin to be noticed about age 40 and will usually get worse quite rapidly over the next few years (presbyopia). This loss of ability to change your focusing distance from far to near will occur whether or not you have refractive surgery.
At any age, if you have the vision in one eye corrected to a natural focus for near tasks such as reading, you will not see clearly with it farther away as the ability to change focus only goes from far to near. The brain adjusts to each eye being focused at a different distance within 6 to 8 weeks. You do not need to consciously make any adjustments.
There is no right or wrong answer to the question of whether to have monovision. This information is to help you make this decision.
In our experience, most people over the age of 40 to 45 who try monovision and take a few months to become accustomed to it, like it and find it very useful. Those who have monovision will be able to generally see well enough both at distance and near to do most things at any age without corrective lenses. Depending on the exact result obtained (as is true for everyone having refractive surgery) there might still be some situations when the very best vision or the maximum visual comfort might require wearing glasses (or possibly contacts). Night driving and prolonged reading are two examples that are mentioned frequently, as well as vision at “intermediate” distance (between 3-10 feet). However, glasses may be required for anything for which you feel the need or desire to have the sharpest possible vision.
It is probably helpful to realize that without a specific cure for presbyopia once you are past the 40-year age range, all refractive corrections involve compromise. If you have both eyes corrected for good distance vision, you will need glasses for close vision. If you have both eyes corrected for close vision (not a common choice) you will need glasses to clearly see everything far away. If you choose monovision, although your vision may work well for almost all purposes, you might feel it is less than perfect.
We know of no perfect way to help you make this choice. We would suggest that if significant doubt remains in your mind, that you aim to have your vision corrected for good general distance vision and plan to use reading glasses when necessary.
It is important to note that if you choose monovision and are unable to get used to it, it can be reversed by performing an “enhancement” procedure on the eye left for near. Once the enhancement is performed, the near eye then sees more clearly in the distance and reading glasses are then required for all near tasks.
Schedule a Consultation Today
The experienced eye surgeons at Ophthalmic Medical Associates, Inc. are dedicating to helping all patients achieve better vision. If you have been considering monovision, schedule a consult at one of our office locations in Hayward, San Jose, Concord or Castro Valley, CA, to learn if you may be a candidate.