EyeWorld Asia-Pacific March 2014 Issue

22 EWAP CAtArACt/IOL March 2014 Brendan VOTE, MB, BS(Qld), FRANZCO Associate Professor, Launceston Eye Institute 36 Thistle Street West, South Launceston, TAS 7248 Tel. no. +613 63441377 Fax no. +613 63441577 eye.vote@me.com T here time for hype associated with femtosecond laser cataract surgery (LCS) has passed, and the ophthalmic community is now looking to researchers to present level II and III evidence when presenting comparisons with current best practice manual phacoemulsification surgery (PCS). It is certainly pleasing to see a randomized trial underway (level II) as presented by Dr. Holzer. The emphasis on safety is important. Our own comparative cohort study, the largest to date, showed reduced safety and increased complications when the femtosecond laser was used. 1 Furthermore, in order to show a 5% difference in BCVA outcomes between LCS and PCS, 95% power calculations indicate a sample size of n=1500 will be needed. The ophthalmic community looks forward to results from this study when more meaningful conclusions can be provided. There is no question that femtosecond laser pretreatment can allow significantly reduced effective phaco time (EPT) as highlighted by both Dr. Holzer and Dr. Schultz. Whether this translates into improved safety remains to be determined, particularly as complications such as corneal decompensation are already very uncommon after PCS (~1/2000). Our own comparative cohort data (level III-2 evidence) has confirmed reduced EPT with LCS was associated with statistically significantly reduced early postoperative inflammation (flare) and corneal stress measures (central corneal volume and endothelial cell loss at day 1 and day 21-28). 2,3 However, long-term follow-up (6 months postoperatively) did not show any significant corneal benefits of LCS over PCS (submitted data). In fact LCS with laser corneal incisions showed significantly worse corneal endothelial cell loss than PCS; while LCS without laser corneal wounds was significantly better than PCS (and LCS with wounds), particularly when zero EPT was achieved. Intraoperative aberrometry certainly is an exciting technology offering potential for significantly improved visual outcomes. Whilst Dr. Fisher’s study design only supports conclusions about intraoperative aberrometry improvements to femtosecond laser cataract surgery, it is likely similar improvements would be realized with intraoperative aberrometry used in manual surgery. The influence of intraoperative aberrometry over and above LCS was certainly promising with a 10% improvement in 20/40 BCVA and ~25% improvement in 20/25. However, Dr. Fisher suggests by association that femtosecond laser is playing a role in these improved outcomes. Most manual surgeons using modern biometry achieve similar outcomes to Dr. Fisher’s LCS benchmark (80%) and certainly significantly better than historical PCS data of 50-55%. Our comparative cohort data for MCS using non-optimized biometry is 79.5% MAE ±0.5D and 93.5% ±1 D. LCS (n=405) did not show any statistically significant improvement over PCS (n=215) though numerically slightly better outcomes (83.5% ±0.5 D MAE and 96.3% ±1 D MAE). The opththalmic community looks forward with interest to level II and III evidence of long-term refractive outcomes for both intraoperative aberrometry and femtosecond laser using prospective comparative cohorts of both LCS and PCS. As identified by Dr. Holzer, “there is little difference between the techniques,” so it is not surprising that at current cost to patients the femtosecond laser is not cost-effective. 4 Until better quality trials are published, based on the current published evidence, manual cataract surgery remains the gold standard, and femtosecond laser a technology in development and research. References 1. Abell RG, Davies PE, Phelan D, Goemann K, McPherson ZE, Vote BJ. Anterior capsulotomy integrity after femtosecond laser-assisted cataract surgery. Ophthalmology. 2014 Jan;121(1):17-24. 2. Abell RG, Allen PL, Vote BJ. Anterior chamber flare after femtosecond laser-assisted cataract surgery. J Cataract Refract Surg . 2013 Sep;39(9):1321-6. 3. Abell RG, Kerr NM, Vote BJ. Toward zero effective phacoemulsification time using femtosecond laser pretreatment. Ophthalmology. 2013 May;120(5):942-8. 4. Abell RG, Vote BJ. Cost-Effectiveness of Femtosecond Laser-Assisted Cataract Surgery versus Phacoemulsification Cataract Surgery. Ophthalmology. 2014 Jan;121(1):10-6. Editors’ note: Dr. Vote has no financial interests related to his comments. Views from Asia-Pacific