Assessing the change in visual quality and predicting the postoperative visual acuity following small-incision lenticule extraction for high myopia

Session Details

Session Title: Presented Poster Session: Keratorefractive Surgery Results II

Venue: Poster Village: Pod 2

First Author: : A.Gyldenkerne DENMARK

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

Abstract Details

Purpose:

Small-incision lenticule extraction (SMILE) and refractive surgery in general is known to increase higher-order aberrations (HOA). HOA decrease the image quality, but they also interact; a visual quality metric, the log Visual Strehl Ratio (logVSR), is based on the entire wavefront aberration. The logVSR was used in this study to assess the change in visual quality following SMILE.

Setting:

University eye clinic

Methods:

One eye of 42 patients measured before and 3 months after SMILE for high myopia was analyzed in this study. Measurements included high-contrast visual acuity, subjective refraction, autorefraction, and ocular HOA. The logVSR was calculated from the HOAs before and after surgery to calculate the change in visual image quality. Vector analysis was performed to correlate the subjective refraction and autorefraction with postoperative UDVA, and the postoperative logVSR was correlated with postoperative UDVA. Statistical analysis was conducted using paired t-tests and linear regression.

Results:

The spherical equivalent changed from -7.60±1.16 D to -0.23±0.43 D following SMILE. The change in logVSR from -1.04±0.38 before surgery to -1.11±0.40 after surgery was not statistically significant (p=0.41). Spherical aberration increased 0.046 mm (p<0.001) and total coma increased 0.044 mm (p<0.001). Postoperative UDVA was most highly correlated with the blur vector calculated from subjective refraction (p<0.001, R2=0.77), followed by the blur vector calculated from autorefraction (p<0.001, R2=0.52), and the postoperative logVSR (p<0.001, R2=0.40).

Conclusions:

Despite statistically significant changes in ocular total coma and spherical aberration, the image quality measured by the logVSR only decreased slightly and statistically insignificantly following SMILE. The postoperative UDVA is well predicted by the blur vector calculated from subjective refraction.

Financial Disclosure:

None