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The use of one eye for distance 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 if you are over the age of 40.
Monovision has been used successfully for over 25 years with contact lens correction and with various types of refractive 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. Monovision is not the best of both worlds, but for many people such as lawyers and reporters who continually focus back and forth between close and distance objects, monovision provides the best alternative for accomplishing their goals.
Frequently Asked Questions About Monovision
The change in accommodation (focusing ability) to see objects at near will generally begin to decline around the age of 40 and will usually get worse quite rapidly over the next 10-15 years (presbyopia). Presbyopia, loss of ability to change your focusing distance from far to near, will occur whether or not you have refractive surgery. This is the reason people over the age of 40 generally need magnifying glasses (readers) to see up close.
There is no right or wrong answer to the question of whether to have monovision. This information is to help you make this decision.
As a rule, we suggest against monovision if you are under the age of 35 for two reasons:
- It will be a number of years before you will notice any benefit from it; and...
- It is very possible that there will be a better (or at least as good) surgical way to help presbyopia by the time it is a problem for you.
We also generally recommend against monovision at any age for people who may need to see better than average for distant tasks. Some examples might be pilots, race car drivers, someone who drives for a living (especially at night), and avid tennis players (especially for playing at night), etc.
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, but it could be anything for which you feel the need or desire to see the very best possible. 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 made to see 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. Below you will find the answers to frequently asked questions about monovision. If you have any further questions regarding your care, please contact us.
MONOVISION FREQUENTLY ASKED QUESTIONS
If I choose to have monovision, does that mean I will never need reading glasses?
No. Presbyopia continues to worsen as you get older, whether or not you have monovision. At some point, the presbyopia may be so bad that reading glasses will be necessary. Still, there is a benefit to having the monovision because there won't be a complete dependence on glasses for things up close. Larger print will still be readable without glasses, and things slightly farther away (like computers and dashboards of cars) will still be readable. Without monovision, even these things would be blurry without reading glasses. For this reason, patients usually don't "give up" their monovision as they get older. They still read better with the monovision than they would if both eyes are corrected for distance, even though for certain things, reading glasses become necessary.
What will the vision be in my reading eye with monovision?
The distance vision in the eye set for reading will be less than 20/20 for distance. The reading eye is left slightly near sighted to allow for better close vision. The amount of residual nearsightedness may be different for different patients, depending on age at the time of surgery, how "good" the patient wants the reading to be, how much distance vision they are willing to give up, and how long they want to be able to read before they eventually need reading glasses. Typically, the amount of nearsightedness left will be between -1.00 and -2.00 diopters. On average it is -1.50 diopters. Regardless of how many residual diopters of nearsightedness are left to allow for the monovision, the vision on the eyechart cannot be predicted just by looking at this number. There is no conversion between diopters and visual acuity on the eyechart (20/20, 20/30, etc.). In other words, if you are left with -1.50 diopters of residual nearsightedness you may see 20/40 with that eye in the distance, or you may see 20/100, 20/80 or 20/50. It can be and is different for different people. In any case, it is not really important how each eye sees separately, it is a two eye world and what is important is how you see with both eyes open you and are you able to comfortably see both near and far for most of your needs.
I tried monovision with contacts and didn't like it. Will it work better with surgery?
It may, and it may not. Part of it depends on how it was tried with the contact lenses. Was it tried for a day, or for a month or more? Sometimes it takes awhile for the brain to "adjust" to this way of seeing. Were the contact lenses properly fit? Was the proper eye set for distance? Was there any astigmatism that needed to be corrected that wasn't with the contacts? Even if everything was done "right" there is certainly a chance that monovision didn't work well. Some of these people have gone on to have surgery, and have tried monovision with surgery and have liked it. Some still did not like it, even with surgery. There may be some contact lens problems that people attribute to monovision problems, and that is why some people may do well with it, even if the contacts didn't work well.
How do you decide which eye to do for distance and which for near?
There are several factors involved. One is, which is the dominant eye? Usually, but not always, the dominant eye is set for distance. Sometimes a patient will come in who has been wearing contacts for monovision and the dominant eye is set for near. If this has been done for awhile, and the patient is doing well with the monovision, we will keep it this way and correct the non-dominant eye for distance. Some patients have a large difference between the measurements in the two eyes. One eye may be -4.00 diopters and the other may be -8.00. Even if the -8.00 diopter eye is the dominant eye, we might make that the reading eye in order to minimize the amount of treatment each eye gets. Part of the purpose of the comprehensive eye exam is to look at all of these issues and decide what will work out best.
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LASIK SECRET #8
After the age of 40, most people need reading glasses to see up close. LASIK does not correct the need for reading glasses unless you choose monovision as an option. Monovision is designed to reduce one's dependence on reading glasses. Call us today @ 888-887-2010 to have all of your LASIK questions answered.
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