Posters

Lenticule thickness deviation in small incision lenticule extraction: a target – actual comparison using spectral domain OCT

Poster Details

First Author: M.Ring AUSTRIA

Co Author(s):    N. Luft   M. Bolz   M. Dirisamer   T. Kreutzer   T. Haslwanter   S. Priglinger     

Abstract Details

Purpose:

To evaluate the precision of lenticule thickness in small incision lenticule extraction (SMILE) with the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) for the treatment of myopia.

Setting:

Ars Ophthalmica Study Center, Department of Ophthalmology, General Hospital (AKH) Linz, Austria

Methods:

This prospective observational study included twenty patients that underwent uneventful SMILE surgery. Anterior segment SD-OCT (RS-3000 Advance; NIDEK Co. Ltd., Gamagori, Japan) was used to assess the central corneal stromal thickness before and multiple times after surgery. Planned maximum (central) lenticule thickness was compared to the measured decline in central corneal stromal thickness 1 week, 6 weeks as well as 3 months, 6 months and 12 months postoperatively.

Results:

Forty eyes of twenty patients were included and mean age was 35±7 years. Mean spherical equivalent of the extracted lenticules was 5.22±1.57 diopters and mean lenticule thickness was 100±21 µm. Preliminary results showed that on the first postoperative day the actual stromal change observed with SD-OCT was 23±7µm lower than the programmed lenticule thickness (p<0.01). This discrepancy decreased to 19±8µm, 16±5µm and 18±5µm after 1 week, 6 weeks and 3 months, respectively (all with p<0.01).

Conclusions:

Programmed lenticule thickness was found to be higher than the observed decrease in stromal thickness during the first 3 postoperative months after SMILE. These differences might be explained by postoperative corneal edema, subsequent corneal biomechanical remodeling or alignment errors of pre and postoperative measurements. A comprehensive analysis of lenticule thickness accuracy and corneal stromal remodeling in the first 6 postoperative months as well as eventual impact on refractive and visual outcomes will be presented.

Financial Disclosure:

NONE