Factors influencing the outcome of small incision lenticule extraction for myopic astigmatism

Session Details

Session Title: Moderated Poster Session: Trends in Refractive Surgery

Venue: Poster Village: Pod 1

First Author: : A.Ivarsen DENMARK

Co Author(s): :    A. Gyldenkerne   J. Hjortdal                    

Abstract Details

Purpose:

To determine factors influencing the postoperative outcome after small incision lenticule extraction (SMILE) for myopic astigmatism.

Setting:

Department of Ophthalmology, Aarhus University Hospital

Methods:

A total of 829 eyes of 829 patients (324 male, median age 37 years) were treated with SMILE for myopia with an astigmatism of 1.00 diopter (D) or more. SMILE was performed with a Visumax femtosecond laser. Patients were examined before and 3 months after surgery with subjective refraction and Pentacam HD. Cylinder data was evaluated by vector analysis and multiple linear regression.

Results:

Preoperative subjective cylinder averaged 1.71D. With-the-rule (WTR) and against-the-rule (ATR) astigmatism was observed in 73% and 16% of eyes, respectively. Backsurface astigmatism (BA) averaged 0.40D, and 91% of eyes had a net ATR BA. Multiple linear regression was used to predict magnitude of error (ME) from age, gender, left/right eye, target induced astigmatism (TIA), subjective ATR/WTR astigmatism, and BA. The model significantly predicted ME (R2=0.23, p<0.001) with TIA contributing -0.15 D per attempted diopter (p<0.001) and subjective ATR astigmatism contributing 0.33 D (p<0.001). BA, age, gender, and left/right eye had no significant impact on the outcome.

Conclusions:

Almost 25% of the variation after SMILE for myopic astigmatism may be explained by the size of the attempted cylinder correction and ATR/WTR astigmatism. By incorporating these parameters in the preoperative planning, more consistent results should be obtainable in high cylinder corrections.

Financial Disclosure:

None