Many French ophthalmologists still prefer microkeratomes

There are scientific, clinical, ergonomic and financial reasons why practitioners are favoring microkeratomes over femtosecond lasers.

PARIS — Several years after the introduction of femtosecond lasers in LASIK, the majority of French ophthalmologists still use microkeratomes, according to one surgeon speaking at the meeting of the French Society of Ophthalmology.

“Currently, more than two-thirds of LASIK procedures are performed with microkeratomes, also in the clinics where a femtosecond laser is available,” Jean-Marc Ancel, MD, said.

There are scientific, clinical, ergonomic and financial reasons behind this choice, he explained.

Scientific, clinical reasons

Thin flaps are no longer an exclusive advantage of femtosecond lasers, because new microkeratomes, such as the Moria One Use-Plus, can be used to perform sub-Bowman’s keratomileusis. In addition, Hansatome (Bausch + Lomb) users can obtain thinner flaps by lifting the microkeratome head while maintaining a constant inverse pressure on the suction ring, Dr. Ancel said.

“In our cases series, the Visante OCT showed that with IntraLase 60 Hz (Abbott Medical Optics), Moria One Use-Plus and B+L Hansatome 160, mean flap thickness was quite similar, with a slightly wider standard deviation in the Hansatome group,” Dr. Ancel said.

A second argument in favor of microkeratomes is that surface regularity is better, he noted.

“Scanning electron microscopy showed that femtosecond lasers produce a less regular surface. Cavitation bubbles make iris registration impossible in 10% to 20% of the cases, and the presence of tissue bridges can make flap lifting more difficult,” he said.

A potential drawback of femtosecond laser LASIK is interface inflammation due to the energy of the laser and the diffusion of gas through the endothelial pump. Keratocyte activation, visible by confocal microscopy as areas of hyperreflectivity, is increased in more than 25% of cases.

“Pain and delayed visual recovery are common consequences of inflammation,” Dr. Ancel said.

In his opinion, safety can no longer be used as an argument in favor of femtosecond lasers. Time and a longer follow-up are beginning to show that the risk for ectasia after LASIK might not be lower with femtosecond lasers.

“Cases have been found, and we are likely to conclude that the rate of this particular complication is comparable with the two techniques,” he said.

Ergonomic, financial reasons

Ergonomically speaking, femtosecond lasers are less user-friendly and patient-friendly than microkeratomes, he said. The patient needs to be moved from the femtosecond laser to the excimer laser, and the procedure time is lengthier, particularly during suction and flap lifting. Suction can also be more painful.

“Furthermore, femtolasers are delicate machines which need regular maintenance and frequent servicing. Their availability is not constant and not predictable, which affects surgery schedules and planning,” he said.

The issue of cost can also shift the balance in favor of microkeratomes.

“The cost of microkeratome LASIK is approximately €82 per eye, while femto-LASIK is €210 including the purchase and the maintenance of the machines. Calculating an average of 1,000 procedures per year, the difference in 5 years is €640,000 less with the [One Use-Plus] Moria, and €800 to €900 less with the Hansatome,” he said. – by Michela Cimberle

• Jean-Marc Ancel, MD, can be reached at 52 Avenue du Roule, 92200 Neuilly sur Seine, France; +33-1-47222094; fax: +33-1-47220213; e-mail: dr.ancel@wanadoo.fr.

Mechanical microkeratomes compare very favorably with femtosecond lasers for creating flaps with comparable sub-Bowman's flap thicknesses, few complications, smoother beds, less inflammation and at a fraction of the cost. As a matter of fact, we don't need to switch to a much more costly method of creating flaps, with essentially no benefits.

Future studies should look at further evolutions of both mechanical keratomes and femto-lasers; both will improve, but I suspect that the outcomes will be very comparable for many years, while the price of doing business with the femtosecond laser manufacturers will always be far more costly, with the price being passed to the patient.

Vive le difference et vive la France!!

– Richard A. Norden, MD, FACS
Norden Laser Eye Associate, Ridgewood, NJ, USA

It is true that some microkeratomes, under adequate conditions, can perform similarly to femtosecond lasers. The problem is that the variability in long series is, no question, much worse for the mechanical microkeratomes than the femtosecond. Energy problems are no longer such an issue, as recently developed 60- and 120-kHz femtoseconds really do not have the incidence of diffuse lamellar keratitis that they had previously, and surface quality is equivalent at this moment.

Clinical practice with mechanical microkeratomes is indeed the state of the art in many countries. However, I cannot see the future with mechanical microkeratomes with the femtoseconds on the market. Financial issues are on a short-term basis, and in the long term, all flaps will be created with femtosecond because of obvious advantages in quality control, repeatability, stability of the flap design and control. Since I have used the femtosecond technology, complications are minimal although never absent. I strongly support the future for femtoseconds rather than for mechanical microkeratomes.

– Jorge L. Alió, MD, PhD
OSN Europe Edition Board Member

• Dr. Alió has done research for IntraLase Corporation (Abbott Medical Optics).