Are IOL designs holding back Femtosecond Laser Assisted Cataract Surgery?
Lens fragmentation pattern following FLACS. Courtesy of Boris Malyugin MD, PhD, Nikolay Sobolev MD and Natalia Anisimova MD, S Fyodorov Eye Microsurgery Complex State Institution, Moscow, Russia
Designing intraocular lenses (IOLs) to take advantage of the precision afforded by femtosecond laser-assisted cataract surgery (FLACS) will likely encourage FLACS development and adoption, according to experts who spoke at the Ophthalmology Futures Forum Barcelona 2015, in Spain.
“I don’t think the lack of lenses today is retarding femtosecond cataract technology; it is going forward by itself. But there is huge potential for IOL improvement. If new IOL technology gives a benefit to femtosecond laser surgery there will be a synergetic effect that will propel this complex forward in the years to come,” said Boris Malyugin MD, PhD, Chief of Cataract and Implant Surgery at the S Fyodorov Eye Microsurgery Complex, Moscow, Russia, who moderated a panel discussion on the topic.
However, with current IOLs the benefits are unclear, so some surgeons advised caution in adopting FLACS. “My clinic has a mission statement and the first sentence is ‘patient satisfaction is the number one priority’. Right now I can’t justify femtosecond cataract surgery because it does not improve the performance of current lenses,” said Arthur Cummings MB, ChB, MMed(Ophth), FCS(SA), FRCSEd, of Wellington Eye Clinic, Dublin, Ireland.
FUTURE LENS DESIGNS
That could change quickly, Dr Cummings added. “If future lens designs have real benefits – I’m thinking real accommodation – and they fit better in an eye treated with a femtosecond laser, that is what will drive (widespread FLACS adoption).”
For example, FLACS might one day make possible emulsifying and removing cataracts, through a very small incision, followed by re-inflation of the capsular bag with an accommodating gel, he added.
A decade of follow-up with the bag-in-lens design by Marie-José Tassignon MD, PhD, FEBO, shows that capsulotomy-fixated lenses are stable, resisting anterior movement associated with capsule fibrosis and contraction over time. Better stability may also allow larger IOL optics offering better vision quality, he said.
Sunil Shah MBBS, FRCOphth, FRCS (Ed), FBCLA, a consultant ophthalmologist at Midland Eye, Solihull, UK, is conducting a study of the LENTIS IOL, focusing in part on outcomes with less-experienced surgeons. His early results suggest that the technology may produce better results even among surgeons with 20 or fewer procedures, but it’s still too early to tell for sure.
IS FLACS BETTER?
Before looking to new lenses that optimise FLACS, the question of whether femtosecond technology is superior to phacoemulsification should first be addressed, said Béatrice Cochener MD, PhD, Professor and Chair of the Ophthalmology Department at University Hospital Brest, France.
She underlined that, actually instead of asking if femto is better than phaco, we should consider that we are not comparing two competitive techniques but just refining phaco with femto for potentially better safety and accuracy.
“Is perfect lens centration guaranteed to perfect positioning of the lens? We don’t have an answer for that. Will the capsular bag act the same after FLACS as it does after phaco? We don’t know,” she said.
Another issue with FLACS is it can make polishing the capsule more difficult, increasing the risk of posterior capsule opacification (PCO), Dr Cochener added. This could gravitate against FLACS because overcoming PCO is a major issue in improving outcomes.
“We need to think about what we need to eliminate in cataract outcomes, we need to improve predictability of IOL positioning and to eliminate PCO,” she added.
Early results of a multicentre French study will focus, among the various evaluated parameters, on the occurrence of PCO. Fibrosis and bag contraction may appear earlier after femtocataract, but it is too early to tell for sure, or if the differences is significant, Dr Cochener said.
“We need to see if FLACS itself is better than phaco alone, and then come back to evaluate specific lenses that need to be designed to achieve the targeted perfection of predictable and stable implantation,” said Dr Cochener.
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