Current presbyopia correction techniques involve a few complications but are gradually improving, according to one surgeon.

New cornea-based procedures may be on the horizon, Mark G. Speaker, MD, PhD, said during Refractive Subspecialty Day preceding the American Academy of Ophthalmology meeting.

U.S. Food and Drug Administration-approved surgical techniques for treating presbyopia include monovision LASIK, conductive keratoplasty and IOL implantation. Techniques under investigation include synthetic keratophakia, new multifocal IOLs and multifocal excimer laser ablation, and femtosecond laser applications in the cornea and lens. 

“Presbyopia, when we consider using surgical corrections, must be viewed as a transition, a progression,” Dr. Speaker said. “Cataract surgery is the last stop on that progression. Since the onset of presbyopia precedes the onset of cataracts, the optics of a corneal procedure for presbyopia have to be compatible with IOL optics or else be reversible.”

Evolving procedure

“The status of multifocal or presby-LASIK is certainly evolving,” Dr. Speaker said. “This technique improves distance and near vision in hyperopes but does not correct near vision very well in myopes. We need to get better near results, especially in myopes, and this will require optimizing ablation patterns.”

Synthetic keratophakia, which involves the use of corneal inlays in the nondominant eye, can improve near vision without significantly compromising distance acuity and is reversible.

“The advantage is significant in that it’s exchangeable, so as the patient progresses and needs more correction, it can potentially be changed. If the patient is unhappy or at the time of cataract surgery it needs to be removed, it can be reversed. And also it’s nice for refractive surgeons because it’s an adjunctive technique to LASIK,” he said.

The three corneal inlays under investigation are the AcuFocus (Bausch & Lomb), PresbyLens (ReVision Optics) and Invue (Biovision). Dr. Speaker said in one study, the PresbyLens restored uncorrected near visual acuity on postoperative day 1 in 100% of patients and yielded distance uncorrected visual acuity of 20/25 or better in all eyes.

“While the femtosecond has certainly transformed the way we create LASIK flaps, I think that … there’s a lot of potential for it to change our thinking about presbyopia,” he said. “Intrastromal femtosecond laser treatment of the cornea for presbyopia has been reported using the B&L and Femtec lasers. [The results] are quite impressive. Remarkably, there doesn’t seem to be a loss of contrast sensitivity.”

However, there is scant data to support the technique’s safety and efficacy in humans. Femtosecond laser incisions in the crystalline lens are also being investigated as a means of restoring elasticity and accommodative range in animal models.

“It remains to be seen whether this approach can reverse presbyopia in human eyes without inducing cataract, but it’s certainly an exciting opportunity,” Dr. Speaker said.

Pharmacologic agents slow elasticity loss

The use of pharmacologic agents may slow or stop the decline of elasticity in the crystalline lens, Dr. Speaker said. For example, reversatrol, an antioxidant found in red wine, inhibits lipid peroxidation and angiogenesis and may be able to prevent or reverse presbyopia.

“The cleanest way to take care of the problem would be to use pharmacologic inhibition of loss of lens elasticity in the crystalline lens,” he said.

“Current presbyopic surgery produces aberrations that are not accepted by all patients,” Dr. Speaker said. “Contrast sensitivity loss may be less, though, with presby-LASIK and inlays than with multifocal IOLs. And unlike lensectomy with IOL, corneal surgery is time-limited by the progression of presbyopia and the development of cataract.”

However, combined corneal-lens procedures may emerge in the next 5 years.

“A two-stage approach for reversal of presbyopia is something that’s yet to be achieved, but I think we’re getting closer,” he said. – by Matt Hasson