Thursday, February 7, 2013

Wednesday, January 23, 2013

Monovision Laser Vision Correction: An Alternative to Reading Glasses



One of the most common questions we hear from prospective patients over the age of 40 is:  “Am I a candidate for LASIK or PRK laser vision correction if I only need reading glasses?”  The answer may surprise you:  It's yes!  The common misconception is that laser vision correction is only for patients who are lifelong glasses or contact lens wearers.  However, with the advantage of the monovision approach, patients who only wear reading glasses can also benefit from the procedure.  Even better news:  For those patients who truly have 20/20 distance vision in each eye without corrective lenses, the laser vision correction procedure is half the price, since only one eye is corrected.

Monovision is a tried and true approach to avoiding or minimizing the need for reading or computer glasses, and is a laser vision correction procedure in which one eye is optimized for distance vision and the other for near vision tasks.  With monovision correction, although both eyes are still working together, one eye is relied upon much more for distance, while the other eye is relied upon for near, which is why it’s called monovision (from the term monocular, meaning one eye).   Your brain has neuroplasticity,  so you can train your brain to automatically, and seamlessly, switch between the eyes as you change your focus from near to distant objects, and vice versa.  Monovision is also commonly used as a customized option in LASIK and PRK laser vision correction procedures for those patients who are either nearsighted or farsighted and over the age of 40 who have lost their ability to see clearly up close.

In order to understand monovision, you need to understand how the visual system works, as well as some key ophthalmic terms.  When a patient reaches their mid 40’s and loses the ability to accommodate, (or adjust their focusing power for near vision) they need bifocals or reading glasses.   This condition is called presbyopia, and the lenses used to correct this condition are plus powered lenses which enable the patient to see clearly for near vision tasks.  In a normal sighted eye, light rays from distant objects are focused directly on the retina to produce a clear image without the need for corrective lenses.  In a nearsighted (myopic) eye, the eye is anatomically longer than that of a normal sighted eye.  Therefore, light rays from distant objects come into focus before they reach the retina.  This condition results in an eye that cannot see clearly in the distance, but can see clearly up close (without the help of corrective lenses).  This is the concept that is employed in monovision correction.

All patients have a dominant eye, which is the eye that is preferred for visual tasks.  In the monovision approach, the non-dominant eye is purposely made slightly nearsighted to optimize reading vision.  This means that vision in that eye will be clearer up close for near vision tasks, but blurry when viewing distant objects.  The degree of correction chosen for reading correction will be customized for each patient’s visual needs.  The factors considered in choosing the amount of correction for reading vision include the refractive error (prescription) of the eye, the patients’ age, profession and hobbies.  The goal for the dominant eye is for it to see clearly in the distance.  If a patient is nearsighted or farsighted, the dominant eye also requires laser vision correction treatment to correct that eye for distance vision.  If a patient has a normal sighted dominant eye, that eye does not require treatment, so only the non-dominant eye is corrected for near vision.

Is it possible to train yourself to adjust to this different type of vision?  YES.  Monovision takes advantage of brain plasticity to help you learn to automatically see both near and far objects. How motivated you are to adapt to this customized vision and take advantage of your brains plasticity, is the best predictor of success with monovision.

Not everyone is an optimal candidate for this type of laser vision correction procedure.  Therefore, a consultation, including a thorough medical eye exam, is necessary to determine whether monovision is the right choice for you.  This type of correction can also be simulated with a contact lens so that patients can see what monovision is like prior to having this procedure.  Monovision correction can also be achieved with contact lenses, but is usually not successful in eyeglasses.

There is a slight compromise with monovision, as two eyes working together typically give you better vision than one eye working alone.  There is also a learning curve to adapt to monovision.  However, after an adjustment period, the motivation to avoid bifocals or reading glasses is usually strong enough to overcome this.  Depth perception can be affected slightly, but usually not enough to affect daily activities.  At Mandel Vision, we do recommend driving glasses until you comfortably adapt to monovision.  Once the brain adjusts to monovision, most patients are very happy with their customized procedure.  Moreover, they are ecstatic that they no longer have to reach for their reading glasses every time they attempt to read a restaurant menu!

Call Mandel Vision® today, at 888-866-3681, for your free laser vision correction evaluation, with corneal surgeon, Eric R. Mandel, M.D., to see if you qualify for this exciting alternative to reading glasses.