COST BENEFIT ANALYSIS FOR FEMTOSECOND LASER IN CATARACT SURGERY

Femtosecond laser offers exciting possibilities for significantly improving cataract surgery precision and outcomes, the XXXV United Kingdom & ireland society of Cataract & Refractive surgeons (UKisCRs) Congress heard. The ongoing discourse in the profession over the revolutionary properties of the femtosecond laser and its increasing applications versus its costs and the potential unknown risks were the focus of a lively session during the second day of the meeting. it was argued that femtosecond laser should always remain in the hands of ophthalmologists as opposed to lower grade clinicians, and that it will probably never completely replace traditional phaco surgery.

Jorge L Alió MD, PhD, instituto Oftalmológico De Alicante, spain, spoke about his pioneering work using the new technology in microincision cataract surgery. Explaining the difference between cornea and lens femtosecond laser applications, he said the femtosecond laser pulses to the anterior capsule and crystalline lens during cataract surgery and requires different parameters from those used by femtosecond laser for corneal surgery. specifically, the newest intraocular femtosecond laser penetrates deeper into the eye: 7.500 microns vs. 1.200 microns for those used in corneal surgery. 'This is a dramatic change and why it is so difficult to have a laser that can make corneal flaps and emulsify them at the same time. And the main difference in the different technologies is the numerical aperture (NA). it defines the focal length of the application of the laser and also the amount of energy you focus on that,' he commented.

Elaborating, Dr Alió said the larger the NA, the smaller the focal spot volume, and the smaller the energy threshold. There are two ways to increase the NA; by increasing the lens diameter or by decreasing focal length, and in either case accuracy is vital. Looking at the technologies currently available, he noted that in 2010 the Us FDA approved femtosecond laser technology to be used in cataract surgery, unusually ahead of Europe. There are currently four companies working with it, though with some variance in imaging – Lensx/Alcon (optical coherence tomography (OCT)), LensAR (confocal structured illumination (scheimpflug)), OptiMedica (OCT), and Technolas (OCT). highlighting what femtosecond surgical systems are capable of, Dr Alió explained they can create corneal incisions (so far only Lensx), perform capsulotomy and photodisruption of the nucleus. Other applications that have been investigated include lens softening (unsuccessfully), while some models (Femtec 520) may also perform refractive presbyopic surgery (intraCor).

Advanced and reliable After studying femtosecond cataract surgery for six years and visiting surgeons with direct handson experience in the different technologies available Dr Alió believes Alcon Lensx is the 'most advanced, complete and reliable laser of all i know'. (he acknowledged that he became a member of the Medical Advisory Board of Lensx in 2010, prior to its acquisition by Alcon.) As one of the few surgeons using the technology as this level, Dr Alió discussed his own results of femtosecond laser clear cornea incisions. he pointed out that the design is controlled and selected by the surgeon and the programming software allows customised geometry and positioning so there is excellent dimension reproducibility. All incisions are self-sealing, the incision quality is objectively excellent and neutral for the corneal optics and there are no surprises, he added. 'Corneal incisions created using a femtosecond laser compared with those using manual blades show laser incisions are more architecturally reproducible,' he maintained.

Discussing his experience with interior capsulotomy using Lensx, Dr Alió said it is highly precise and predictable. specifically it is more accurate, metered and consistent than traditional surgery, it avoids the risk of anterior capsular tear, and is perfectly centred which is a crucial factor for premium iOLs, he noted. it also reduces the induction of higher order aberrations. To support his own findings, Dr Alió quoted the results of a clinical evaluation study of intraocular femtosecond laser in cataract surgery (Nagy et al, J Refract Surg. 2009; 25(12): 1053-1060), which found 100 per cent of Lensx procedures achieved an accuracy of ± 0.25mm while only 10 per cent of manual procedures achieved an accuracy of ±0.2. Looking at femtosecond laser's ability to perform photodisruption of the nucleus, Dr Alió said it allows the surgeon to skip sculpting and chopping steps, using patterns of cuts to soften harder cataracts and help facilitate removal of the nucleus. The technology also reduces the number of instruments used, intraocular movements and manipulation of the lens, plus by minimising the amount of phaco energy needed, it reduces the risk of capsule complications and corneal endothelial injury. in a nutshell, the technology is a perfect fit with the new premium iOLs he told the meeting and has exciting possibilities for better precision and results in this type of surgery. he reiterated the limitations of conventional cataract surgery compared to LAsiK – the poorer visual outcomes, the limits on astigmatism and presbyopia correction, and the higher complication rates.

Expense an issue However, despite his optimism for the potential of femtosecond laser in cataract surgery, Dr Alió acknowledged the 'important concerns among surgeons and administrators about how to deal with the extra expenses to be generated by femto cataract surgery'. Currently it costs over €500 per eye in his practice. he said he remains confident, however, that the price will come down eventually and better management of the costs will make the financial condition manageable. Packages combining premium lens and premium surgery are a likely development in the next couple of years.