IMPROVED CONTROL

A recent French study adds to the growing number of reports suggesting that the femtosecond laser can provide improved control and precision for key steps of the procedure for cataract removal, according to Jean Claude Rigal-Sastourne MD.

Addressing delegates attending the annual meeting of the French Implant and Refractive Surgery Association (SAFIR) annual meeting, Prof Rigal-Sastourne, an ophthalmologist at the Hôpital Percy in Clamart, Paris, said that the femtosecond laser enables surgeons to achieve greater precision, control and reproducibility in their cataract treatments.

“In our experience, cataract removal with the Victus femtosecond laser (Bausch + Lomb) is an easy, reliable and safe procedure to perform capsulotomy and achieve smooth lens fragmentation. It enables us to create accurate, well-centred anterior capsulotomies, which may lead to better IOL positioning and overlap,” he said.

Prospective study        
Prof Rigal- Sastourne’s prospective study set out to compare the results between cataract surgery performed by femtosecond laser and by traditional manual methods looking at three key areas: capsulotomy, ultrasound time and effective lens position after surgery.

The study included 32 eyes of 24 patients operated for cataracts using bimanual MICS and implanted with the Micro AY lens implant (PhysIOL). Half the eyes were treated using the femtosecond laser and half with traditional manual methods. Postoperative examination took place at one week and one month after surgery.

Creating the capsulotomy with the femtosecond laser was found to be an efficient and effective technique with easy removal of the rhexis and without any adverse events. Moreover, the laser-created capsulotomies were significantly more precise in size and shape than manually created capsulorhexes, said Prof Rigal-Sastourne.

The intended capsulotomy diameter in the study was 5.2mm, although the software on the Victus machine allows the size to be customised, said Prof Rigal-Sastourne. After seven days postoperatively, the mean diameter of the capsulorhexis for the Victus group was 5.35mm (± 0.22mm), with 85 per cent of the rhexis within ±0.35mm of the targeted diameter.

A round and symmetric capsulorhexis with the anterior lens capsule overlapping the optic’s edge is optimal for accurate postoperative IOL centration, noted Prof Rigal-Sastourne, with this goal achieved in 100 per cent of the femtosecond- created rhexes.

For the manual capsulorhexis patients, the intended diameter was 5.5mm, whereas the actual diameter of the rhexis after seven days was 6.1mm (±-0.21mm), with 15 per cent of eyes within ±0-35mm of the targeted diameter.

Capsulotomy A statistically significant difference in the circularity of the capsulotomy using the femtosecond laser compared with the manual technique was also observed. Centration was also better with the femtosecond group, said Prof Rigal-Sastourne.

He added that a number of different lens fragmentation patterns, such as ring or radial cuts, can be used and applied depending on the cataract grade. Using the femtosecond laser seems to enable easier cracking of the nucleus following lens fragmentation, which reduces the phaco energy required for lens removal.

“The average reduction of ultrasound energy being delivered into the eye was about 35 per cent in our study, which means greater protection for the endothelial cells and less trauma to the eye,” said Prof Rigal-Sastourne.

The study also found improved effective lens position (ELP) with the eyes treated by femtosecond laser. The reproducible, central and circular capsulorhexis created by the femtosecond laser is a prerequisite for good postoperative effective lens position, especially with the latest premium IOLs, said Prof Rigal-Sastourne. IOL power calculations were also more accurate in the femtosecond-treated eyes, leading to better refractive outcomes.