As Richard Packard, MD, FRCS, FRCOphth, traced the evolution of the capsulotomy from crude forceps to precision laser during his Binkhorst Medal Lecture, he noted a new technology that may improve upon femtosecond cataract surgery.
Billed as the next generation in laser cataract technology, the CAPSULaser is a thermal laser that fits under a surgical microscope and is used only for making a capsulotomy. Perfectly round and precise, and completed in just 3 seconds.
Still in the clinical validation phase, the company expects a commercial launch in late 2015.
“Capsulotomy creation is the most important advantage of femtosecond cataract surgery,” Dr. Packard said. “But what does the capsulotomy look like?”
Research from Dr. Brendan J. Vote shows femtosecond-created capsulotomies have irregularities at the capsule margin, similar to perforations on a postage stamp, which may attribute to the higher rate of anterior capsule tear compared with standard phacoemulsification, occurring at a rate of 1.87% vs. .12% (P=0.0002).
Because the CAPSULaser is continuous, not pulsed like a femtosecond laser, and is scanned in a single circular pattern to create the continuous curvilinear capsulotomy, it creates a smoother capsulotomy, Dr. Packard said.
The technique begins with trypan blue to stain the anterior capsule and create a selective target for the laser. As the laser is scanned in a single circular pattern, the laser energy facilitates the molecular phase change of the capsular collagen IV to elastic amorphous collagen, creating a capsulotomy with a rim that has a high degree of elasticity and tear strength associated with the amorphous collagen.
“Results in 10 patients with 2 months of follow-up showed all corneas were clear and with endothelial count as expected, Dr. Packard said. “And capsulotomies were well-centered and not contracted, and there was no change in IOL position.”
In contrast to the femtosecond laser, preliminary clinical results show no pupil constriction after laser application with the CAPSULaser.
In other symposia held here at ESCRS 2015, speakers presented data showing more evidence of the benefit of femtosecond cataract surgery in complicated cases and pediatric patients.
Burkhard Dick, MD, of the University Eye Clinic Bochum in Germany, said that femtosecond cataract surgery has a distinct advantage in pediatric cataracts, compared with manual surgery. Anterior and posterior capsulotomies in early pediatric cataracts are often challenging due the elasticity of the capsule. The laser alleviates some of the difficulty as it produces perfectly sized, shaped and centered anterior capsule openings, which helps position and stabilize IOLs. It also makes it significantly easier to line up the posterior and anterior capsulotomies.
But on the whole, enthusiasm for femtosecond cataract surgery waned considerably at ESCRS 2015, compared with 5 years ago when the technology was launched.
Some surgeons said they have stopped creating incisions with the femtosecond laser due to reports of localized endothelial cell loss around incisions.
Additionally, 2-year results from the ESCRS Femtosecond Laser-Assisted Cataract Surgery (FLACS) study continued to show that it doesn’t outperform routine phacoemulsification.
Funded entirely by ESCRS, this study is the first to compare femtosecond surgery and phacoemulsification in matched patients who were measured by major quality benchmarks: visual acuity, surgically induced astigmatism, complications and biometric errors.
Dr. Peter Barry, head of the Department of Ophthalmology in St Vincent's University Hospital, Dublin, who delivered the 2-year data, which now includes nearly 3,000 femtosecond cataract cases, said laser surgery showed benefit only in astigmatism reduction.
“The single, biggest benefit was seen in less postop astigmatism and less surgically induced astigmatism,” Dr. Barry said.
Patients in the femtosecond group in the FLACS database tended to be younger, had better preop vision, were more likely to have had previous refractive surgery and were more likely to have a multifocal IOL.
Dr. Barry said the femtosecond cataract patients had “slightly worse postop visual acuity, due to a slightly higher incidence of postop complication, such as higher IOP, uveitis and early PCO. And they had slightly worse postop VA compared to preop VA.”
Oliver Findl MD, Hanusch Hospital, Vienna, Austria and Moorfields Eye Hospital, London, UK, summed up the disappointment this way.
“I thought we would be in a better position. I thought it (femtosecond cataract surgery) would be a game changer,” Dr. Findl said. “I’m a little depressed. It doesn’t seem that way.”