Presbyopia is therefore an age-related need for reading glasses ("cheaters") or bifocals in glasses. It occurs as the natural lens of the eye becomes progressively stiffer with age.
MONOVISION
One option for presbyopic people who wish to avoid reading glasses is to create "monovision" in which the dominant eye is corrected for distance and the non-dominant eye is corrected for close vision. With both eyes functioning as a team, the presbyopic patient can see near and far, all without glasses. Monovision can be an excellent option for presbyopic patients, but there is a downside: the quality of the distance vision is often not as good as if both eyes were corrected for distance. This is particularly noticeable at night or under dim lights. A night-time pair of driving glasses can fill this gap and allow patients to enjoy the other benefits of monovision.
BLENDED VISION
Blended vision, or "mid-monovision," is a less severe variation of monovision. With monovision, the dominant eye is set for distance and the non-dominant eye is corrected for close vision. By contrast, with blended vision, the non-dominant eye is set for mid-range vision, rather than close range, creating less of a disparity between the eyes. Blended vision is often more comfortable for patients and tends to minimize the distance impact of monovision. Unlike monovision, the goal of blended vision is not to eliminate reading glasses altogether, but rather to dramatically reduce their need. With blended vision, presbyopic patients typically can still read a cell phone or write a check without "cheaters," but will often wear a light pair of reading glasses to read a phone book. Blended vision offers patients a different balance of priorities than monovision does -- the emphasis is more on the mid range (where computer screens are) rather than the close -- and also provides better and more comfortable distance vision than monovision does. As with monovision, a night-time pair of driving glasses can help fine tune low light distance vision.
WHO BENEFITS FROM MONOVISION OR BLENDED VISION?
To some people, the idea of having one eye for distance and one eye for closer up sounds strange and imbalanced. In fact, not all patients are good candidates for monovision or blended vision. However, many people are surprised by how much they do enjoy monovision with little or no sacrifice in vision or balance. In fact, the data shows that 80% of people are very pleased with either monovision or blended vision, whereas 20% have trouble adapting to it. We can help determine if you will benefit from either monovision or blended vision before surgery by simulating these two options for you in the office. Ultimately, you will best know how you react to monovision or blended vision by this simulation, giving you a chance to "try on" the surgery before any surgery is done!
Similarly, people who have otherwise never worn glasses in their lives, but now need reading glasses, can be offered monovision or blended vision. For these patients, LASIK is performed only in the non-dominant eye to allow it to see closer and the dominant eye is left untouched for distance, allowing the team of both eyes to see well near and far without glasses.
Questions? Please email us at shapirolaser@sbcglobal.net
