Research and development continues on multifocal LASIK (also called Presby-LASIK) as a means to restore near vision lost to presbyopia.
The goal of these procedures is to expand the range of vision for presbyopic refractive surgery patients over age 40 and reduce their dependence on reading glasses.
Early results of Presby-LASIK
Recently, prominent LASIK researcher W. Bruce Jackson, MD, professor of ophthalmology, University of Ottawa Eye Institute (Ontario, Canada) offered these findings of ongoing PresbyLASIK research in an article in Ophthalmology Times magazine:
- Bilateral (both eye) treatments appear to work well, but monocular presbyLASIK may be a good alternative.
- Most patients are satisfied with the visual outcomes of presbyLASIK, but tend to want more near vision over time.
- When correcting hyperopia (farsightedness), distance vision after presbyLASIK is comparable to distance vision after monofocal LASIK.
- PresbyLASIK can result in a loss of p to two lines of best-corrected visual acuity (BCVA) as measured on a standard eye chart.
- The re-treatment rate is higher after presbyLASIK than it is after monofocal wavefront-guided LASIK.
- PresbyLASIK appears to provide visual outcomes that are similar to multifocal IOLs after cataract surgery or refractive lens exchange.
Dr Jackson noted that there are different techniques being tested and evaluated for Presby-LASIK. In some varieties, the central part of the cornea is treated for near vision and in others the central cornea is shaped for distance vision and the periphery of the cornea contains the near vision correction.
“Peripheral-near” Presby-LASIK
According to Dr. Jackson, a review of published outcomes of the center-distance, near-periphery multifocal approach indicates that about 80 percent of presbyopia patients achieve binocular distance uncorrected visual acuity (UCVA) of 20/25 or better and 100 percent attain binocular near UCVA of 20/30 or better, which typically is adequate to read a newspaper without reading glasses.
But there appears to be a significant difference in patient satisfaction among different studies. For example, one study says 100 percent of patients receiving presbyLASIK were satisfied with their distance and near vision after surgery, whereas another study found that only about 50 percent of patients were satisfied with their distance and near vision after the procedure.
“Center-near” Presby-LASIK
Dr Jackson is one of several researchers who are evaluating presbyLASIK using a laser ablation pattern that treats the center of the cornea for near vision and the peripheral cornea for distance vision in the correction of hyperopia and presbyopia.
He says that, when using this approach on 56 eyes of 28 hyperopic patients, 100 percent of eyes had distance UCVA of 20/25 or better and near UCVA of 20/30 or better. And 88 percent of eyes at one treatment center had near UCVA of 20/20.
Dr. Jackson also reported that another surgeon using the center-near presbyLASIK approach on a patient population that included individuals with hyperopia and individuals with myopia prior to surgery found that 88 percent of eyes achieved binocular UCVA of 20/25 or better at distance and 20/30 or better at near.
Awaiting FDA approval
At the time of this posting, Presby-LASIK has not received FDA approval for use by refractive surgeons in the United States. But several investigators are continuing research on this multifocal LASIK treatment worldwide, and with outcomes as promising as those noted above, many believe FDA approval will come in the relatively near future. FDA approval would add PresbyLASIK to a list of previously approved LASIK variations, such as LASEK and Epi LASIK eye surgery.
SOURCE: Laser correction of presbyopia viable but still investigational. Ophthalmology Times. May 1, 2009.
Tags: farsighted, vision correction