Multifocal LASIK for Presbyopia Correction
Multifocal is also known as presbyLASIK can be referred to as an advanced type of laser eye surgery or laser vision correction surgery. The shape of the eye’s cornea is changed in this surgery so that there can be different power zones that can see from distinct variations.
This procedure fixes the presbyopia as the eye’s natural lens begins to lose its focusing flexibility most probably after the age of 40, which causes the near vision to blur. For instance, there are contact lenses, multifocal eyeglasses, and progressive lenses worn by individuals to have a clear vision.
How LASIK for Presbyopia Works:
There are these multifocal corneal treatments that help individuals with this condition to be able to have a clear vision of the things at distance without wearing multifocal eyeglasses, reading glasses, or bifocals. These treatments are created by the manufacturers of femtosecond lasers and excimer lasers.
There are two main ways in which this procedure fixes the condition:
1) Your cornea is reshaped into three different zones for near, far, and intermediate vision by the excimer laser. Depending on the object’s distance on whether it’s near or far, the brain chooses the specific zone in which an individual can see through the sharpest vision.
2) Just as the multifocal contact lenses that’s how it corrects presbyopia, the different zones help the individuals to have a good vision from all directions as the light is refracted differently.
One major difference between multifocal contact lenses and this procedure is that unlike multifocal contact lenses, which rests upon the eye’s surface, can move and distort the vision. This type of LASIK is fixed with three zones directly on the surface of the eye that cannot distorts the vision.
Additionally, multifocal contact lenses, progressive eyeglass lenses, and multifocal LASIK, all of these have multiple designs and various approaches towards the correcting and shaping of cornea’s vision to achieve the best flexibility.
The Distance Vision to be Centered in PresbyLASIK:
Robert L. Epstein, a refraction surgeon and the director of the Mercy Center for Corrective Eye Surgery in Chicago, supports this type of LASIK with a central zone for the scope of vision. He says, “I chose this approach because of the possibility of easy reversibility to pure monofocal distance correction, should be needed.” He continues, “I felt this was safer than the opposite approach, where the peripheral cornea is corrected for distance and the center for near.”
The Near Vision to be Centered in PresbyLASIK:
Jorge L. Alio, a professor of ophthalmology at Instituto Oftalmologico de Alicante, supports the peripheral zone for distance vision to be in the center of the cornea shaped for near vision by a multifocal ablation. This approach will cause fewer aberrations as compared to the distance center ablations because it will also provide the surgeons with a stronger correction for near vision tasks such as reading.
The Refractive Error in the LASIK for Presbyopia:
There are different designs as discussed above. Your eye surgeon will help you in deciding which design is best suited for your specific refractive error and vision needs. For instance, a distance – center multifocal LASIK design will be best for those individuals who have near sightedness. The same goes for a near – center multifocal LASIK design that will be best for those individuals who have far sightedness. Both of the designs are prescribed for those who have presbyopia.
Modified Monovision PresbyLASIK:
There is another approach where you can have this surgery performed in one eye and a standard LASIK surgery performed in another eye. This surgery is known as modified monovision. This approach provides a sharper distance vision as compared to multifocal LASIK surgery performed on both eyes. However, it comes with certain disadvantages as it will require you to wear reading glasses more often which can reduce the depth perception in the sight.
According to Dr. Epstein, with any kind of LASIK, a strong distance vision is necessary. He supports the modified monovision approach where one eye is supposed to have presbyopia and the other eye is supposed to have wavefront-guided LASIK.
He says, “We just cannot match what (distance – only) wave front-guided LASIK provides for good distance vision.”
A test can be conducted to verify the tolerance for modified monovision. The advantage in multifocal LASIK as compared to straight monovision is that in straight monovision there are only two focal points that are of near and far whereas in modified monovision there is a third intermediate focal point. Dr. Epstein explains, “This gives vision over a broad range of distance”, he further adds, “It’s also much easier to adapt to the milder difference in a correction in the eyes when we use this type of LASIK in the non-dominant eye and wave front-guided distance LASIK in the dominant eye”.
Is There a Possibility of Reversion in this surgery?
According to Dr. Epstein, the reverse of the near vision center zone design surgery is more difficult than the distance vision center zone design. However, if you are unsatisfied with this surgery, there is a possibility of a LASIK enhancement procedure that can fix your distance vision. It has a disadvantage that will make the near vision less clear without reading glasses.
The Level of Effectuality in Multifocal LASIK?
The results of this surgery has a positive outcome as most individuals came out to see 20/20 or 20/25 in the distance. Also, some of them don’t need the glasses at all while reading printed newspapers.
However, there is a possibility that you may have blurry vision after the surgery if you had a normal vision before the surgery. This is a problem for most of the individuals as it may not go away. Some individuals may experience a reduction in contrast sensitivity or may face a tendency to see halos around the lights at night.
Therefore, future enhancements may be required as if there are any changes in the eye after LASIK surgery because there is no guarantee of this surgery whether its effects will be permanent or not.