NEW CATARACT SURGERY TECHNOLOGY

Cataract surgery performed with femtosecond lasers has several potential advantages over conventional phacoemulsification with ultrasound, but it may also represent another step towards the automation of surgery that will leave the surgeon handicapped by the constraints of the machines that they use when difficult situations arise, according to participants in a debate at a JCRS symposium at the XXX Congress of the ESCRS. Taking the argument in favour of the new technology, H Burkhard Dick MD, PhD, Ruhr University Eye Clinic, Bochum, Germany, said that femtosecond laser cataract surgery has four principal advantages. “First is the rapid adoption of the procedure, by both surgeons and patients. Second is the ease and precision it allows in the creation of corneal incisions and capsulotomies. Third is the reduction or elimination of the need for ultrasound, which is especially true when performing extensive nuclear fragmentation, and fourth is the potential to improve existing techniques and create new ones,†he said.

The main disadvantage of femtosecond laser cataract surgery is the increased expense compared to conventional ultrasound. Currently the various systems cost about half a million euro. In order to break even a surgeon would have to perform femtosecond laser procedures in 250 eyes during the first year and in 350 eyes in the second year with an added surcharge of €1,500 in each case. However, Dr Dick said that so enthusiastic has been the acceptance of femtosecond laser cataract surgery that he was able to perform more than 960 cases in nine months, on a commercial basis without advertising, and he expects to exceed three times his quota for breaking even by two years. One of the driving factors of its popularity is that it can be used in “all comers,†he continued. That includes many of the more difficult cases, such as hard cataracts, small pupils, intraoperative floppy iris syndrome and eyes with comorbidities, including corneal guttata and glaucoma.

He noted that, in the Catalys Precision Laser System (OptiMedica Corp) that he uses, the low suction of the fluid filled Liquid Optics interface leaves the conjunctiva unchanged, even in patients receiving anticoagulant therapy. Moreover, the interface also only increases IOP by a mean of 10.0 mmHg and is therefore safe to use in eyes that have undergone trabeculectomy. Regarding the reduction in the need for ultrasound in femtosecond laser cataract procedures, Dr Dick said that out of his first 850 cases, 40 per cent required no ultrasound phacoemulsification. In addition, there was a 96 per cent reduction in effective phaco time across all grades of cataract compared to manual phacoemulsification. The precision it adds to the performance of capsulorhexes may also make femtosecond laser cataract surgery especially suitable for use with premium IOLs, such as those with aspheric, toric and multifocal designs. A precisely shaped and sized capsulorhexis can help insure the good centration and stability that such lenses require. “When we look at the literature, laser cataract surgery is better concerning capsulorhexis parameters, IOL position, internal aberrations and optical and predictability of IOL power. The studies also show less corneal trauma and swelling and comparable postoperative macular thickness,†Dr Dick added.

From surgeons to technicians

Femtosecond lasers can offer precision and control over many aspects of cataract surgery, but a skilled surgeon using older technology can produce equivalent results at less expense. Moreover, the extra control the machines afford is control that is taken from the surgeon’s hands, said Steve Arshinoff MD, University of Toronto, Toronto, Ontario, Canada. “My issues with femtosecond laser cataract surgery are really that it takes a part of the art of cataract surgery away from us, and it is not as adaptable to the unusual circumstances that we often meet in cataract surgery,†he added. He noted that for a long time phaco surgeons were considered great artists, but in more recent years various technologies have been developed that are designed to replace surgical technique with commercial products.

Examples include the use of toric IOLs in place of limbal relaxing incisions, and the use of multifocal IOLs in place of monovision. Now there is the femtosecond laser, which is designed to replace diamond knives for creating incisions and bent needles and forceps for performing capsulorhexes. “As more and more of the art of our procedures is being removed and taken over by machines, the income trend for doctors will go down and that for companies will go up,†Dr Arshinoff added. The replacement of surgical skill and experience by technology could, in the whole surgical process, reduce the role of surgeons to that of technician. The future may see companies recruiting surgeons fresh from medical school or residency to work in corporate surgical centres at very little pay for very little skill. Furthermore, many of the supposed advantages of femtosecond laser are not really proven. The reduction in phaco time most investigators report is around 33 per cent rather than 90 per cent as reported by Dr Dick, he said. In addition, there have been reports of adverse events such as incomplete capsulorhexes.

The expense of the devices will also make them unavailable to most surgeons and to most patients in the world. There are still many places in the world where surgeons cannot afford conventional ultrasound phaco. He added that history has shown that what ultimately makes any new surgical technology become part of standard practice is its ability to enable surgeons to do things that were previously impossible and which improve patients' outcomes, usually at fairly low cost per case. “I want the femtosecond laser to make me feel that I can do new things that I could not do before, that my surgical art has been enhanced, not replaced and that I’m not a servant of some big corporation,†Dr Arshinoff added.