FEMTOLASER SURGERY

The LenSx® (Alcon) femtosecond laser system is highly flexible in the performance of cataract surgery and may provide some important safety advantages over conventional ultrasound phacoemulsification, said Prof Jacek P Szaflik MD, PhD, Medical University of Warsaw, Poland. “The biggest advantages are repeatability of capsulorrhexis shape and size and lens fragmentation that is individually adjusted for the type of cataract and preference of the surgeon, and the reduction in phacoemulsification power decreases the risk of endothelial cell loss and macular oedema,” Prof Szaflik told a symposium of the Polish Society of Cataract and Refractive Surgery at the 17th ESCRS Winter Meeting. He presented a prospective analysis comparing the results in 80 patients who underwent femtosecond laser cataract surgery using the LenSx platform with those of a matched group of patients who underwent standard phacoemulsification. The patients’ cataracts ranged from grade 1 to grade 5. The analysis showed that the amount of phacoemulsification energy used per procedure was 43 per cent lower among those undergoing a femtosecond laser procedure than it was among those who underwent manual phaco. Furthermore, among the femtosecond laser group endothelial counts were lower than preoperative values by only 1.8 per cent at one month and by only 3.2 per cent at six months. By comparison, among eyes in the manual phaco group endothelial cell counts fell by 5.8 per cent at one month and by 17.25 per cent at six months. Femto-cataract plus DSAEK Prof Szaflik also presented results achieved in a series of 46 patients who underwent combined DSAEK and cataract surgery with the femtosecond laser. Fuchs’ dystrophy was the indication in 45 eyes, and two eyes had primary endothelial dysfunction. 

Prof Szaflik and his associates used the LenSx femtosecond laser (Alcon) to create the capsulotomy and chop the nucleus. They implanted round endothelial grafts of 8.5mm diameter or oval grafts sized 8.0mm by 9.0mm. Although docking was not possible in one case and three capsulotomies had to be created manually in three cases, the surgeries were uneventful. There was one case of graft detachment two days after the surgery that required air injection, after which it became fully attached and clear. “Femtosecond laser capsulotomy and nucleus fragmentation can be performed in presence of endothelial lesions and mild to moderate corneal oedema. In cases with very oedematous cornea attention should be paid whether the capsulotomy is complete. The accurate capsulotomy ensures maintaining good stability of the implant in the capsular bag during the remaining surgery. Employing the femtosecond laser technology facilitates cataract surgery during combined procedure,” Prof Szaflik said.

The femto procedure When using the femtosecond laser, Prof Szaflik and his associates perform the capsulotomy, nucleus fragmentation, corneal tunnels and side incisions with the laser and then complete the surgery using a torsional micro-coaxial phacoemulsification technique. They perform the procedure under local anaesthesia using a palpebral speculum. When the patient looks at the fixation light the interface becomes fixed to the eye and they increase suction to immobilise the eye. Afterwards, they use the laser’s integrated OCT device to check the orientation and position of the cuts in the cornea and the position of the anterior capsule. They also adjust the range of lens fragmentation to avoid cutting the posterior capsule. The lens fragmentation patterns include longitudinal slices that can be combined into a pizza pie configuration and cylindrical cuts. They can be used alone or in combination, Prof Szaflik noted.

“Basically we enter the data so we can precisely define what kind of cuts, what kind of procedure we want to perform, the diameter of the capsular axis, the method of lens fragmentation and the parameters of arcuate incisions. It looks a little complicated but after a couple procedures it becomes very easy to manage and it's pretty user-friendly,” he added. Learning curve Prof Szaflik noted that they had some difficulties with some of their first cases but he said that problems became less common as they gained experience with the system. In addition, the new patient interface (LenSx® SoftFit™) seems to have eliminated the difficulties. In five cases they could not complete docking because of a discrepancy between the size of the patient’s interface piece and the periorbital anatomy and they had to abandon the laser procedures. Four of the abandoned cases were among the first 50 treated and one was among the following 80 eyes. They also had incomplete capsulotomy in eight cases, six among the first 50 cases and three among the following 80 cases. Anterior radial tear occurred in one case, necessitating a manual capsulorrhexis. In one case with a mature white cataract, they could not visualise the posterior pole of the lens with the built-in OCT system and could therefore perform only the capsulorrhexis and corneal incisions. “The new design of the laser has a smaller patient interface and it also allows a shortened time for the laser at a lower energy, so the quality of the cuts is far improved. We’ve also had no problems with docking with the new interface and we’ve also had no incomplete capsulotomies, although even with the old system that didn't happen anymore after we had some practice,” Prof Szaflik added.