Posters

Changes in corneal deformation parameters after lenticule creation and extraction during small incision lenticule extraction (SMILE) procedure

Poster Details

First Author: Y.Shen CHINA

Co Author(s):    J. Zhao   P. Yao   H. Miao   L. Niu   X. Wang   X. Zhou

Abstract Details

Purpose:

To investigate the effect of lenticule creation and subsequent corneal lenticule extraction on corneal deformation parameters during small incision lenticule extraction (SMILE) procedure.

Setting:

Refractive surgery operating room, Eye and ENT hospital, Fudan University, Shanghai, China

Methods:

In this prospective study, 18 eyes of 10 patients (27.90±7.11 years, -5.64±2.45 diopters) scheduled for SMILE procedure were enrolled. Changes in the corneal deformation parameters, including deformation amplitude (DA), applanation time(AT1 and AT2), applanation length(AL1 and AL2), corneal velocity(CV1 and CV2), peak distance(P.Dist.), radius and the intraocular pressure values were measured preoperatively, immediately after lenticule creation and subsequent to corneal tissual lenticule extraction in all eyes with the Corvis Scheimpflug Technology (Corvis ST, OCULUS, Wetzlar, Germany). Repeated measures analysis of variance (ANOVA) with bonferroni-adjusted post hoc comparisons was performed to investigate changes following each step of the procedure.

Results:

All surgical procedures were uneventful. A significant difference was detected among the three time points(pre-operation, post-lenticule creation and post lenticule extraction) for AT1 (P<0.001), AT2(P=0.001), DA(P<0.001), and IOP(P=0.002). Bonferroni-adjusted post hoc comparisons indicated that there was no significant change in AT1, AT2, DA, or IOP after lenticule creation (post hoc P>0.05), but there was a significant decrease in these parameters following subsequent corneal lenticule extraction (post hoc P<0.01), when compared to values obtained pre-operatively. The scheimpflug camera of the Corvis ST demonstrated the intralamellar small gas bubbles formed from the vaporisation of tissue after lenticule creation and a gray zone was observed between the cap and the residual stromal bed after lenticule extraction.

Conclusions:

There is a significant change in corneal deformation parameters following SMILE procedure. The changes may be caused predominantly by stromal lenticule extraction, while lenticule creation with femtosecond laser may not have an obvious effect on corneal deformation properties. FINANCIAL INTEREST: NONE