Femtosecond laser assisted cataract surgery has been one of the hottest topics in ophthalmology for the past few years, but is this just hype? I believe the answer is "no". Femtosecond laser devices are truly the most remarkable advance in cataract surgery since the development of phacoemulsification. This technology optimizes the critical steps of cataract surgery (cataract incision, capsulotomy, and nucleus disassembly).1,2 It creates accurate, reproducible, and customized corneal and lenticular incisions facilitating the subsequent intraocular steps of cataract surgery. There is no doubt that femto-phaco is superior to manual surgery; the main concern presently is how to pay for this technology.
The issue of cost arises with any new technology and is always resolved. This debate is analogous to the ones over previous refractive technologies: laser vision correction versus radial keratotomy, and femtosecond lasers versus mechanical microkeratomes for LASIK flap creation. Whenever a superior technology emerges it ultimately succeeds. I believe femtosecond lasers for cataract surgery is indeed a game-changing technology, and it will ultimately become the preferred way of performing cataract surgery.
By using the best technology for preoperative measurements and IOL calculations, we can significantly improve the predictability in refractive target, so that the main source of uncertainty becomes the final position of the IOL optic. Dr. Warren Hill has elegantly demonstrated this in a number of presentations. There is no doubt that the size and shape of the anterior capsular opening influences this effective lens position (ELP). A study that evaluated the effect of capsulorhexis size found that a larger capsulorhexis (6 mm vs. 4 mm) resulted in an average anterior shift of the IOL optic of 0.23 mm or approximately 0.5 D.3 This is the reason why surgeons optimize their IOL formulas to achieve more consistent refractive outcomes. Creating a perfect capsulotomy that overlaps the IOL optic edge for 360 degrees produces less deviation in ELP and has improved the refractive outcomes of laser assisted cataract surgery according to data presented by Drs. Steven Slade, Robert Cionni, and others over the past two years.
Femtosecond laser devices make cataract surgery safer and less challenging, particularly in difficult cases (i.e., pseudoexfoliation, phacodonesis, ectopia lentis, and mature cataracts). I have personally found the intraocular steps to be easier and quicker to perform, although some minor adjustments in surgical technique are necessary such as releasing the cavitation bubbles prior to hydrodissection. However, the partial pneumodissection that occurs from this gas facilitates nuclear rotation and thus less or no hydrodissection is required. In addition, in my experience with the OptiMedica device, the lens segmentation patterns can create small aspiratable cubes, which considerably reduces and sometimes eliminates ultrasound energy. Time is certainly saved in the OR; however, additional time (approximately 5 minutes total) is necessary for the laser procedure. Modification in workflow does allow this technology to be efficiently incorporated into the surgical routine similar to that required when surgeons transition from mechanical microkeratomes to femtosecond lasers for LASIK. Furthermore, although machine breakdown is possible with any automated device, such an occurrence is extremely unlikely. I have not yet heard of this happening with a femtosecond laser for cataract surgery and there are now approximately 150 devices installed globally and thousands of cases have been performed. In fact, I have never had to cancel a corneal refractive surgical case because my femtosecond (iFS (AMO)) or excimer (VISX Star S4 (AMO) or WaveLight Allegretto (Alcon)) laser was malfunctioning. It is much more likely that the problem occurs with the phaco machine, and this has happened to me on multiple occasions.
There are of course limitations with any technology and surgery. Just like some laser vision correction patients are not good candidates for LASIK or for femto-flaps, and some cataract patients are not good candidates for multifocal IOLs, there are patients who are not good candidates for femto-phaco. Femtosecond laser incisions cannot be created through opaque tissue. Therefore the diameter of the lens cuts depends on the size of the patient’s pupil, lens fragmentation/softening cannot be accomplished in white cataracts, and corneal opacities can cause incomplete corneal and lens incisions. However, it is possible to first mechanically enlarge the pupil with intraocular expansion devices and then safely create lens incisions with the femtosecond laser. This has been accomplished without complications using the Catalys Precision Laser System4, which produces watertight corneal incisions and a minimal rise in IOP.
Why don’t we ask ourselves: If I needed cataract surgery today, which method (manual or laser-assisted) would I choose? For me there is only one choice. I would select laser-assisted, and I expect most other ophthalmologists would too. The femtosecond laser devices for cataract surgery include the LenSx laser (Alcon), Catalys Precision Laser System (OptiMedica Corp.), LensAR Laser System (LensAR Inc.), and Victus (Bausch + Lomb). These lasers make cataract surgery safer, more precise and reproducible. This is not debatable it is fact. Femto-phaco is the future of cataract surgery and the future is here.
References:
- Palanker DV, Blumenkranz MS, Andersen D, et al. Femtosecond laser-assisted cataract surgery with integrated optical coherence tomography. Sci Transl Med. 2010 Nov 17;2(58):58ra85.
- Friedman NJ, Palanker DV, Schuele G, et al. Femtosecond laser capsulotomy. J Cataract Refract Surg. 2011; 37:1189-1198.
- Cekic O, Batman C. The relationship between capsulorhexis size and anterior chamber depth relation. Ophthalmic Surg Lasers. 1999; 30:185-190.
- Dick HB (personal communication).
Disclosure:
Dr. Friedman is a consultant and member of the medical advisory board for OptiMedica.