Monovision is one clinical technique used to deal with the correction of presbyopia, the gradual loss of the ability of the eye to change focus for close-up tasks that progresses with age. The intent of monovision is for the presbyopic patient to use one eye for distance viewing and one eye for near viewing. This practice was first applied to fit contact lens wearers and more recently to LASIK and other refractive surgeries.
With contact lenses, a presbyopic patient has one eye fit with a contact lens to correct distance vision, and the other eye fit with a contact lens to correct near vision. In the same way, with LASIK, a presbyopic patient has one eye operated on to correct the distance vision, and the other operated on to correct the near vision. In other words, the goal of the surgery is for one eye to have vision worse than 20/20, the commonly referred to goal for LASIK surgical correction of distance vision. Since one eye is corrected for distance viewing and the other eye is corrected for near viewing, the two eyes no longer work together.
This results in poorer quality vision and a decrease in depth perception. These effects of monovision are most noticeable in low lighting conditions and when performing tasks requiring very sharp vision. Therefore, you may need to wear glasses or contact lenses to fully correct both eyes for distance or near when performing visually demanding tasks, such as driving at night, operating dangerous equipment, or performing occupational tasks requiring very sharp close vision (e.g., reading small print for long periods of time).
Many patients cannot get used to having one eye blurred at all times. Therefore, if you are considering monovision with LASIK, make sure you go through a trial period with contact lenses to see if you can tolerate monovision, before having the surgery performed on your eyes. Find out if you pass your state’s driver’s license requirements with monovision.
In addition, you should consider how much your presbyopia is expected to increase in the future. Ask your doctor when you should expect the results of your monovision surgery to no longer be enough for you to see near-by objects clearly without the aid of glasses or contacts, or when a second surgery might be required to further correct your near vision.
Bilateral Simultaneous Treatment
You may choose to have LASIK surgery on both eyes at the same time or to have surgery on one eye at a time. Although the convenience of having surgery on both eyes on the same day is attractive, this practice is riskier than having two separate surgeries.
If you decide to have one eye done at a time, you and your doctor will decide how long to wait before having surgery on the other eye. If both eyes are treated at the same time or before one eye has a chance to fully heal, you and your doctor do not have the advantage of being able to see how the first eye responds to surgery before the second eye is treated.
Another disadvantage to having surgery on both eyes at the same time is that the vision in both eyes may be blurred after surgery until the initial healing process is over, rather than being able to rely on clear vision in at least one eye at all times.
If you are considering refractive surgery, make sure you:
- Compare. The levels of risk and benefit vary slightly not onlyfrom procedure to procedure, but from device to device depending onthe manufacturer, and from surgeon to surgeon depending on their levelof experience with a particular procedure.
- Don’t base your decision simply on cost and don’t settle forthe first eye center, doctor, or procedure you investigate. Rememberthat the decisions you make about your eyes and refractive surgery willaffect you for the rest of your life.
- Be wary of eye centers that advertise, ”20/20 vision or your money back” or ”package deals.” There are never any guarantees in medicine.
- Read. It is important for you to read the patient handbookprovided to your doctor by the manufacturer of the device used to performthe refractive procedure. Your doctor should provide you with this handbookand be willing to discuss his/her outcomes (successes as well as complications)compared to the results of studies outlined in the handbook.
Even the best screened patients under the care of most skilled surgeons can experience serious complications.
- During surgery. Malfunction of a device or other error, suchas cutting a flap of cornea through and through instead of making ahinge during LASIK surgery, may lead to discontinuation of the procedureor irreversible damage to the eye.
- After surgery. Some complications, such as migration of theflap, inflammation or infection, may require another procedure and/orintensive treatment with drops. Even with aggressive therapy, such complicationsmay lead to temporary loss of vision or even irreversible blindness.
Under the care of an experienced doctor, carefully screened candidates with reasonable expectations and a clear understanding of the risks and alternatives are likely to be happy with the results of their refractive procedure.
Be cautious about ”slick” advertising and/or deals that sound ”too good to be true.” Remember, they usually are. There is a lot of competition resulting in a great deal of advertising and bidding for your business. Do your homework.
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