Laser Energy Settings and Visual Recovery After SMILE
By Lynda Seminara and selected by Richard K. Parrish II, MD
Journal Highlights
American Journal of Ophthalmology, August 2017
Download PDF
Although small-incision lenticule extraction (SMILE) has many benefits, recovery of visual acuity in the early postoperative period is slower than for other refractive techniques, even with optimization of laser scanning patterns. Ji et al. experimented with different levels of femtosecond laser energy to assess their effect on clinical outcomes. They found that low levels (< 115 nJ) provided the best visual outcome and induced fewer corneal aberrations during the very early postoperative period.
This prospective randomized trial included 151 patients (151 eyes) who underwent SMILE for correction of moderate myopia. Fifty-eight eyes were treated with the femtosecond laser on low energy settings (100-110 nJ), and conventional energy settings (range, 115-150 nJ) were used on 93 eyes. The same surgeon performed all procedures. Complete ophthalmic exams were performed preoperatively and at the 1- and 3-month marks postoperatively.
Surgery was uneventful in all patients. Uncorrected distance visual acuity (UDVA) at day 1 and week 1 following surgery was significantly better for the low-energy group; in contrast, substantially more corneal aberrations were induced by conventional energy at these time points. Within 1 to 3 months postoperatively, these between-group differences were not significant.
The investigators concluded that laser energy levels below 115 nJ lead to rapid visual recovery after SMILE and reduce the likelihood of corneal aberrations during the immediate postoperative period. They postulated that the lower levels may yield a better optical interface surface and emphasized that more research is needed to determine optimal laser settings for different systems and platforms.
The original article can be found here.