Monovision
Monovision means one eye set for distance vision and the other eye set for near vision and reading. This is done in an attempt to significantly reduce the need for glasses in most daily life circumstances. Most patients who are successful with monovision are glasses free, except possibly driving at night or for detailed 3 dimensional near work such as sewing, woodcarving, etc. Usually the dominant eye is set for distance and the non-dominant eye is set for near vision.
How to check your eyes for dominance
- While wearing your distance correction (glasses or contacts if used for distance), make a circle with your thumb and forefinger.
- Hold the circle you made with your finger and thumb at arms length. Now with both eyes open, look at a small distant object through the circle.
- While still viewing it, close one eye and then the other to see which eye was focused on the object (only in one eye will the object be visible).
The eye that could still see the object is your dominant eye! This is often the eye with the least nearsightedness, farsightedness and astigmatism, and the eye you would use to look through a camera viewfinder or telescope.
The great majority of patients begin their experience with monovision by trying it with contact lenses. This is often around age 40, when distance contact lenses no longer work for distance and near vision, because of presbyopia (loss of ability to focus). If they are successful with monovision contact lenses, they will almost always be successful if they choose to have refractive surgery set for monovision, such as NuSite™ Advanced Surface Ablation, or Refractive Lens Exchange (RLE). A few patients are born with natural monovision and occasionally a patient has monovision as the result of previous cataract or other eye surgery in one eye. In both cases the patient has usually already adapted to monovision and wants to maintain this effect.
The important factor in all these scenarios, is that the patient has already experienced monovision, has adapted to it, and likes this effect. Patients who have already adapted to monovision are almost always "shoe ins" for this effect with cataract surgery and should almost always choose this method. They are some of our happiest patients, since they are usually not wearing any glasses at all for most of their daily activities. Also, since this surgery is performed with the monofocal (Tecnis™) IOL (covered by insurance), there is no extra out-of-pocket costs for this effect.
There are two problems with monovision. First, only 50% of people that try monovision can adapt to this effect, with the other half bothered by feelings of imbalance, a "swimming" effect, visual confusion, or even nausea. Those that can adapt usually do so very quickly, and often feel normal with good distance and near vision within a day. Second, patients with cataracts usually are unable to have a good trial of monovision with contact lenses prior to surgery since the cataract blurring would prevent a good visual trial. Since only 50% of patients will adapt to monovision, we never recommend this method unless the patient has already been successful with it currently or in the past. If surgery were done without a trial and you could not adapt, a second surgery would need to be done to reset the eye to match the other side.
