The merits of FLACS

The ESCRS-EUREQUO femtosecond laser-assisted cataract surgery (FLACS) study questioned whether femto outperforms conventional phacoemulsification. According to the results of this case-control study, the answer to that fundamental question is ‘no’, said Peter Barry MD at the XXXIII Congress of the ESCRS in Barcelona, Spain.

Explaining the caveat, Dr Barry noted the importance of considering what the study did and did not measure. The study did measure anticipated surgical difficulty, ocular comorbidity, peri-operative complications, monofocal versus premium intraocular lenses (IOLs), postoperative complications, best corrected visual acuity (BCVA), biometry prediction error, and postoperative cylinder and surgically-induced astigmatism (SIA).

“We did not measure circularity or centration of the capsulorhexis, absolute phacoemulsification energy, the laser platform used, endothelial cell loss, effective lens positioning, or higher order aberrations. These are not unimportant, but there were no comparisons in the database,” explained Dr Barry, St Vincent’s University Hospital and Royal Victoria Eye and Ear Hospital, Dublin, Ireland.

The ESCRS FLACS study included data from 2,814 FLACS cases entered prospectively into the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO) database and 4,987 controls entered into EUREQUO in 2014. These were identified retrospectively and matched for precisely the same preoperative BCVA, age within two years, and scoring the same ‘yes’ or ‘no’ for the EUREQUO fields on ocular comorbidity and anticipated surgical difficulty. All FLACS cases were performed by surgeons who had exceeded a 50-case learning curve and all reported cases were consecutive.

SIGNIFICANT BENEFIT

Summarising the results, Dr Barry reported FLACS was associated with a statistically significant benefit for minimising the incidence of postoperative astigmatism of equal or greater than 1.5D (nine per cent vs 18.5 per cent). The results were similar in an analysis excluding cases with a toric IOL, concurrent femtosecond laser refractive surgery, or a history of corneal refractive surgery. In addition, SIA of greater than 0.5D occurred at a significantly lower rate with FLACS compared with phacoemulsification (47 per cent vs 53 per cent).

However, postoperative BCVA was worse after FLACS than in the phacoemulsification group. The proportion of eyes with worse BCVA postoperatively than preoperatively was significantly higher in the FLACS group than in the phacoemulsification group (3.3 per cent vs 1.3 per cent). This is important because the preoperative visual acuities were the same as the result of the matching process. This worse vision was due to postoperative complications, not to previous corneal refractive surgery. The worse BCVA outcomes with FLACS were due to a higher rate of postoperative surgical complications – corneal oedema, early posterior capsular opacification and uveitis requiring treatment. Femto currently does not outperform phaco, Dr Barry concluded.

Peter Barry: peterbarryfrcs@eircom.net