FEMTO CATARACT

There are a number of compelling reasons for making the switch from traditional phaco to femtosecond laser-assisted cataract surgery including faster visual rehabilitation, reduced complications and reduced exclusion criteria for cataract surgery, according to Burkhard Dick MD. “Femtosecond laser technology has come a long way in a very short space of time and I am amazed how quickly this technology is developing. In my practice, we are now close to completely eliminating ultrasound for cataract removal. Around 99 per cent of my last 400 cases have been performed without ultrasound,” Dr Dick told delegates attending the XXXI Congress of the ESCRS in Amsterdam.

Beyond the often-cited advantages of customisable corneal and lenticular incisions and precise and reproducible capsulotomies with the femtosecond laser, Dr Dick emphasised some of the other key benefits of the technology. “In prospective, randomised trials of the femtosecond laser-assisted system, endothelial cell loss, corneal swelling and bag shrinkage were reduced compared to standard phacoemulsification. Visual rehabilitation was also faster, with best-corrected visual acuity better up to one week after surgery. By effectively eliminating the need for ultrasound, we can now perform surgery in routine cases without having to use viscoelastic. It works extremely well in complicated cases such as Marfan's Syndrome, intumescent and advanced cataracts and small pupils,” he said.

Dr Dick uses the Catalys (OptiMedica) system incorporating a “Liquid Optics” patient docking interface and an image-guidance system, which identifies ocular surface and establishes safety zones to allow the physician to select and customise the treatment. “The interface is very smooth and stable and results in a minimal IOP increase of the order of 10 mmHg. The guidance system and automatic surface detection means that the laser pulses are delivered precisely to the intended location. Capsulotomy is performed in less than two seconds, with minimal cavitation bubbles and very quiet eyes postoperatively,” he said.

Learning curve

Making the transition to femtosecond laser-assisted cataract surgery has made a dramatic difference to the need to use ultrasound energy in routine cases, said Dr Dick. “When we started we saw a clear decrease in the use of effective phaco time (EPT) by 96 per cent in a controlled trial across all grades of cataract. We also found that by tightening the fragmentation grid pattern from 500 to 350 microns, we were further able to reduce the EPT,” he said. As with any technology, there is a definite learning curve with femtosecond laser-assisted cataract surgery, noted Dr Dick.

“It really is all about optimisation and that comes with experience. My first 200 to 400 cases showed that I still used ultrasound in 59 per cent of cases. Then changing to 350-micron grid spacing we were able to reduce this to 38 per cent for cases 700 to 900. For cases 1200 to 1400 with a new phaco tip and adjusted settings, it was less than nine per cent where I still had to use ultrasound. And in the last series of cases, ultrasound was required in just three out of 400 eyes. Those three cases were grade four cataracts, which means that for 99 per cent of my cases now I do not use any ultrasound at all, just irrigation and aspiration,” he said.

Contrary to expectations, Dr Dick noted that the reduction in ultrasound energy being delivered into the eye did not result in either a higher fluidics usage or longer procedure times. “In a prospective intraindividual comparative trial we measured the fluidics turnover in standard phaco versus femtolaser-assisted group and we saw no significant difference. Likewise, the procedure time was measured from docking on to wound closed and it is very similar for both techniques – whether it is a standard procedure or a laser procedure,” he said.

Many advantages

Other benefits which were confirmed by the prospective trial included a reduction of inflammation by about 20 per cent on day one after surgery, less corneal thickening up to one month postoperatively, less endothelial cell loss after three months, less capsular bag shrinkage and better visual acuity for the first week only, he added. Turning to complications, Dr Dick said that he experienced four capsular tears in his first 1,273 cases, which included patients with pseudoexfoliation and intumescent cataracts.

“Three of these incidents were due to my lack of experience because I underestimated movement of the eye. This translates to an anterior capsule tear rate of 0.16 per cent and the same for posterior tears, which still compares favourably to the published data,” he said. With improved fixation of the eye and using a dimpledown technique with a cannula directed at the centre of the capsulotomy, Dr Dick said that he has reduced the tear rate even further, with an anterior capsule tear of 0.2 per cent and no posterior capsule tears for the most recent 1,000 cases.

Overall, Dr Dick said that adopting the Catalys system has meant a reduction in the exclusion criteria for cataract surgery, as opacified corneas, loose zonules, intraoperative floppy iris syndrome, pseudoexfoliation and small, nondilating pupils no longer preclude from Femtosecond laserassisted surgery, he said. “I think this technology represents the future of cataract surgery. There are exciting ongoing improvements such as the new technique of intraoperative primary posterior capsulotomy which may help to reduce PCO, and the development of new IOLs which are specifically designed for this femtosecond laser technology,” he concluded.