Two eyes, two lasers, same patient: Schwind's ESIRIS versus Wavelight's 400Q

Schwind's ESIRIS and Wavelight's 400Q laser systems are equally efficacious in correcting refractive error, according to a study presented by Yannis Aslanides, MD of the Emmetropia Mediterranean Eye Clinic in Crete, Greece.

The Wavelight system produces a 400 Hz laser repetition rate versus the 200 Hz rate of Schwind's ESIRIS. Other key technological features include eyetracking (400Q: semi auto eyetracker with locking system, ESIRIS: full auto eyetracker with no locking system) and low energy at focus level (400Q: around 1.60 mJ, ESIRIS: around 0.50 mJ).

Aslanides and a team of colleagues studied the performance and safety of these two excimer laser platforms in 23 patients (13 males, 10 female; age 21-59 years), with each patient receiving treatment in both eyes, but one eye with ESIRIS and the second with 400Q. Both eyes were treated at the same session.

The team performed LASIK in 42 of the 46 eyes and PRK in the remaining four eyes. The Moria M2 microkeratome was employed for each LASIK procedure.

Postoperatively, subjects achieved uncorrected visual acuity (UCVA) of 0.7 to 1.5 (preoperative range was counting fingers to 0.6) and best-corrected visual acuity (BCVA) of 0.9 to 1.5, versus a preoperative BCVA of 0.7 to 1.2. Spherical equivalent (SE) refraction was recorded at -1.25 to plano postoperatively, from a preoperative SE refraction of -7.625 to +4.75.

Overall, 75% and 83% of ESIRIS and Wavelight eyes, respectively, were within ±0.5 D of target refraction. Of the remaining ESIRIS eyes, 100% were within 0.75 D of target, while 91.5% of remaining 400Q eyes were within 0.75D and 100% within 1 D of target refraction.

Aslanides conceded that there was no significant difference between the platforms in terms of refractive outcomes, with no adverse events or loss of UCVA or BCVA being recorded for either platform.

He concluded that both Schwind's ESIRIS and Wavelight's 400Q laser platforms were safe and effective for primary refractive corrections and the laser repetition rate does not appear to be important in achieving accurate visual outcomes.

Ophthalmology Times Europe reporting from the XXIV Congress of the ESCRS, London, 9-13 September, 2006.