Technology: Timing is everything

Oct 01, 2012

Viewpoints vary on rediness of femtosecond laser-assisted cataract surgery

Leading surgeons agree that the femtosecond laser will be part of cataract surgery in the future, but have differing opinions on whether the technology is ready for prime time.

Cautious surgeons might ask if it is too early to become involved with the laser, whether it will make a difference in their outcomes, and if patients will appreciate the technology.

"We are seeing universal patient excitement about the laser and numerous ophthalmologists choosing the procedure for their own cataract surgery," said Dr Cionni, medical director, The Eye Institute of Utah, Salt Lake City, USA. "During the year we've had the femtosecond laser, we've had a 36% increase in cataract procedure volume along with increases in the proportions of patients who are opting for astigmatic correction and advanced-technology IOLs."

However, Dr Barrett expressed guarded optimism as he reviewed the purported advantages of femtosecond laser-assisted cataract surgery and questions that remain to be resolved prior to greater adoption of the technology.

"I believe femtosecond laser-assisted cataract surgery is the future," said Dr Barrett, professor, Lions Eye Institute, Nedlands, Western Australia. "For now... we are at a peak of inflated expectations, and we may still experience a trough of disillusionment before complications are minimized and surgeons become more familiar with the technology.

"For the moment it may be prudent for cataract surgeons to pause and defer its purchase as the femtosecond laser may not be ready for prime time," he said.

The true advocate's view

Changes in the cataract surgery patient population are driving the need for advances that can deliver successful outcomes with increased predictability, Dr Cionni noted.

"Patients coming for cataract surgery today are different from the ones surgeons dealt with a decade ago," he said. "The baby boomer population is now Medicare age; they represent a large and rapidly growing segment of the population; and they are well-educated, more financially secure, have a longer life expectancy, will work longer, and demand higher quality of vision. As a result, my cataract clinic today feels more like a refractive surgery center."

"Using a femtosecond laser, surgeons can consistently create a capsulotomy with the desired size, shape, and centration to achieve increased predictability of IOL position," Dr Cionni said. "They can make corneal entry and arcuate incisions of precise length and geometry, and using the laser to pre-treat the lens, we can reduce phaco time and power needed for lens removal."

He supported these claims by reviewing results achieved at his own center for groups of eyes that underwent cataract surgery with standard manual techniques or a femtosecond laser (LenSx, Alcon Laboratories, Fort Worth, Texas, USA). There were 26 eyes in the manual group and 22 that had capsulotomy, lens fragmentation, and the corneal incision performed with the femtosecond laser. The attempted capsulotomy diameter was 5 mm in both groups, and attainment of the desired size in the manual group was facilitated using a 5.75-mm optical zone marker as a guide. All eyes had <1 D of astigmatism and no astigmatic corrections were performed. All patients received the same aspheric monofocal IOL (SN60WF; AcrySof IQ, Alcon). The two groups were comparable in their preoperative demographics and mean axial length, keratometry, and anterior chamber depth.

At 1 month after surgery, there were statistically significant differences favoring the femtosecond laser group compared with the manual group in mean absolute error from predicted refraction (0.26 versus 0.34 D), proportion of eyes within 0.25 D of target refraction (77% versus 54%), and proportion of eyes achieving UCVA of 20/25 or better (82% versus 54%).

In addition, there was better ELP predictability in the femtosecond laser eyes, and postoperatively measured ELP correlated with preoperative anterior chamber depth in eyes that had the femtosecond laser procedure, but not in the manual group.

Data from follow-up to 6 months showed little change in refraction in the femtosecond laser group but a shift in refractive error in eyes that underwent standard manual surgery, Dr Cionni noted.

"The good news is that the shift in the manual surgery group was to a better mean refractive outcome, but the bad news is there was significant variability in the change," he said. "At 6 months, the femtosecond laser group still had better UCVA outcomes than the manual group as well as less total aberrations and less defocus."

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