FEMTO OR PHACO?

Large prospective comparative cohort series found little difference in safety or visual outcomes between femtosecond (FS) laser-assisted cataract surgery and standard phaco surgery, Brendan J Vote MD, Tasmanian Eye Institute, Launceston, Tasmania, Australia, told the XXXII Congress of the ESCRS in London.

The study examined 4,080 consecutive cases operated by five surgeons at a single regional day surgery centre from May 2012 through to November 2013, Dr Vote reported.

Patients mostly self-selected into the laser or phaco groups based on cost – about AU$750 additional for laser. However, about five per cent were assigned to phaco because laser was contraindicated due to age below 22 years, extensive corneal scarring, corneal ring inlays or past glaucoma filtration surgery.

Overall, 1,852 cases ended up in the laser group and 2,228 in the phaco group. Mean age, gender, PNS cataract grade and ocular comorbidities were similar between the two groups.

While intraoperative complication rates were low in both groups, statistically significant differences were observed. The laser group experienced 30 anterior capsular tags, a 1.62 per cent rate, versus one in the phaco group (P=0.0001), though these are generally not clinically significant.

However, 34 anterior radial tears occurred in the laser group compared with five in the manual group (P=0.0001). The anterior tear rate did not change significantly from the first to the second half of the series, suggesting minimal effect of a learning curve, Dr Vote said.

There was, however, no significant difference in posterior capsular tear complications, which are those typically considered more clinically relevant. Corneal haze was more frequent in the laser group, with 12 cases versus one in the phaco group (P=0.0009). Docking vacuum appeared to cause haze, Dr Vote noted. Unstable pupils were also more frequent in the laser group at 30 versus 14 (P=0.003).

Dr Vote also noted a trend toward more cystoid macular oedema in laser cases. Visual outcomes were assessed in 933 laser and 895 phaco cases. Baseline best-corrected distance vision was worse in the phaco group, logMAR 0.4 +/- 0.3 compared with 0.34 +/- 0.24 in the laser group (P<0.0001). The laser group also utilised more toric lenses at 47.7 per cent compared with 34.6 per cent in the phaco group (P<0.0001).

Laser cases achieved slightly better absolute mean distance corrected visual acuity after surgery, at logMAR 0.09 versus 0.13 for the phaco group (P<0.002).

However, the phaco group improved more, gaining a mean 13.5 letters compared with 12.5 for the laser group (P<0.03). The laser group also ended up with a larger mean absolute error.

“The visual benefits of laser cataract surgery have yet to be clearly established. As all of us are aware, cost effectiveness or the lack thereof for laser cataract surgery remains a significant obstacle to the uptake of this technology,” Dr Vote said.

Brendan J Vote: eye.vote@me.com