EyeWorld Asia-Pacific June 2016 Issue

June 2016 EWAP FEATURE 15 Femtosecond cataract surgery: Is it as good? by Steven G. Safran, MD, PA W hen femtosecond laser assist for cataract surgery was introduced I really had a hard time understanding why anyone who could make a reliable rhexis consistently with a cystotome/forceps would bother with it. At a time when there is and was significant pressure on healthcare providers to be more efficient and cost effective the idea of adding a half million dollar laser to cataract surgery that cost 300–500 dollars extra per case to use made no sense to me. We all heard the hype about the “LASIK-like refractive outcomes” a geometrically perfect, round rhexis would provide, but this claim defied logic then and now. Intraocular lenses, after all mostly come in half-diopter steps (whereas excimer lasers can be fine tuned to 0.01-diopter treatments) and there never was any evidence to suggest that the size and shape of the rhexis plays a significant role in effective lens position (nor is there any good reason to suspect that it might). It’s no surprise that most of these claims have fallen by the wayside as study after study has failed to show a significant refractive benefit on spherical outcomes with FLACS versus manual cataract surgery (MCS). It was also suggested by proponents of the laser that we would need this to make a rhexis compatible with the “new accommodating lens technology coming down the pike” but 6 years later there is no such lens and nothing that I’m aware of in the pipeline coming any time soon. The other claims that were made for FLACS were that it would provide superior incisions, more accurate astigmatic cuts, and reduce phaco energy leading to safer surgery. Studies however have failed to show any significant refractive or safety benefit for FLACS versus manual and the question now is not whether it is better than MCS but rather...is it as good? Although we had been assured on roll out that the femtosecond laser-created rhexis was actually stronger than the one created with a manual tear this claim was mostly based on a single study looking at dead pig eyes. 1 In live human patients on the other hand the quality of the rhexis created by the laser has been demonstrated to be markedly inferior to manual tear when compared under scanning electron microscopy (SEM). After experiencing a 15x higher radial tear out rate with FLACS versus MCS Abel, Davies et al. decided to examine their torn capsules with SEM and found that the femtosecond laser capsules had “zipper like jagged edge marred by postage stamp perforations and aberrant pulses which are strikingly different than the smooth edge created manually.” 2 Their findings have been confirmed by others. 3 It is now clear that while the laser-created rhexis looks beautiful to the naked eye it is not so pretty when examined up close and that this may actually make a difference in terms of surgical complications. There have been numerous papers by different investigators now showing an increase in inflammatory mediators caused by use of the femtosecond laser at the beginning of the case. Schultz et al. found that “prostaglandins rise immediately after femtosecond laser treatment” and stated this as likely a causative factor for miosis associated with use of the laser. They recommended that Figure 2. Same patient 1 week after MCS 20/25 uncorrected. Source (both): Steven G. Safran, MD, PA Figure 1. A 95 year old with black HM cataract. continued on page 16 Steven G. Safran, MD, PA