Initial Single-Site Experience Using SMILE for the Treatment of Astigmatism in Myopic Eyes and Comparison of Astigmatic Outcomes with Existing Literature

Majid Moshirfar, Andrew C Thomson, William B West Jr, MacGregor N Hall, Shannon E McCabe, Robert J Thomson, Yasmyne C Ronquillo, Phillip C Hoopes, Majid Moshirfar, Andrew C Thomson, William B West Jr, MacGregor N Hall, Shannon E McCabe, Robert J Thomson, Yasmyne C Ronquillo, Phillip C Hoopes

Abstract

Purpose: To assess a single site's initial experience with SMILE for the treatment of myopic astigmatism and compare outcomes and vector analysis results with the US Food and Drug Administration (FDA) results and published literature.

Patients and methods: Forty-eight eyes (29 patients) with mean preoperative sphere of -5.11 ± 1.31 diopters (D) and cylinder of -1.12 ± 0.60 D underwent SMILE. Visual acuity, refractive, and vector analysis outcomes as well as subjective measures were reported at three and twelve months postoperatively and compared with FDA results and the published literature between 2014 and 2020 involving treatment of patients with mean cylinders of >-0.50 to ≤-3.00 D.

Results: At three and twelve months, 43 and 32 eyes were evaluated, respectively. At twelve months, mean cylinder power was reduced to -0.38 ± 0.38 D with 78.1% achieving ≤±0.50 D. Uncorrected distance visual acuity (UDVA) ≥20/20 was achieved in 77.4% of eyes by twelve months with 100% achieving ≥20/30 UDVA. No loss of corrected distance visual acuity was observed in eyes seen at twelve months. Correction index (CI) at twelve months was 0.90 indicating overall undercorrection of 10%. Twelve-month CI was 0.96, 0.90, and 0.83 in eyes with preoperative cylinders of <-1.00 D, ≥-1.00 to <-2.00 D, and ≥-2.00 D, respectively. Mean angle of error was -1.58 ± 11.61° ranging from -24.22° to 37.75°.

Conclusion: We found SMILE to be an effective and safe means of achieving spectacle independence and improving visual acuity in patients with myopic astigmatism. SMILE has the potential for improved clinical outcomes with better nomogram guidance and advancements in technique. However, surgeons must be aware of the potential for undercorrection in with-the-rule astigmatism and at higher preoperative cylinders and as well as the potential for overcorrection in against-the-rule and lower preoperative cylinder astigmatism.

Keywords: ReLEx; SMILE; astigmatism; myopia; toric; vector analysis.

Conflict of interest statement

The authors report no conflicts of interest in this work.

© 2020 Moshirfar et al.

Figures

Figure 1
Figure 1
Standard reporting graphs for three- and twelve-month outcomes of eyes treated with SMILE.
Figure 2
Figure 2
Double angle vector diagrams for three- and twelve-month target induced astigmatism and difference vector.
Figure 3
Figure 3
Comparison of vector analysis outcomes with other studies.

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