But conventional intraocular lenses (IOLs) used for cataract procedures are monofocal lenses, meaning they have only one power. Therefore, most people who undergo cataract surgery are dependent on reading glasses for near vision.

And even with advances in refractive cataract surgery, many people have residual refractive error after surgery and need prescription eyewear for driving as well.

For people who want greater independence from glasses after cataract surgery, there is good news: Researchers in South America recently reported that presbyopia-correcting multifocal laser vision correction after cataract surgery is safe and can reduce dependence on eyeglasses after surgery.

Multifocal laser vision correction after cataract surgery: Study design and methods

At the recent 2009 annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS), Gustavo Tamayo, MD, of Bogota Laser Refractive Institute in Bogota, Columbia, reported the results of presbyopia-correcting laser vision correction performed on 22 eyes that had undergone successful cataract surgery at least six months earlier.

All eyes had phacoemulsification cataract procedures with implantation of monofocal IOLs, and all eyes had best-corrected visual acuity (BCVA) of 20/20 after surgery.

But all patients in the study were dependent on eyeglasses after cataract surgery: All needed glasses for reading, 17 wore glasses for distance and near vision, and four wore contact lenses.

For their follow-up laser vision correction, four eyes under went multifocal LASIK and 18 eyes underwent multifocal LASEK. In all cases, the eyes received a wavefront-guided multifocal ablation with a peripheral corneal zone shaped for near vision.

Results and conclusions

After multifocal laser vision correction, all eyes had improved uncorrected visual acuity (UCVA) at distance and near, and all subjects were less dependent on prescription eyewear.

No eye lost distance BCVA from the laser procedure, and halos and other visual symptoms increased only slightly after surgery. Patient satisfaction with the visual outcomes of the laser procedures was very high, Dr. Tamayo said.

SOURCE:  Presbyopic laser vision correction reduces spectacle dependence in pseudophakes. Ophthalmology Times. Meeting E-News. Published online April 4, 2009.

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.