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Comment
. 2023 May;71(5):1849-1854.
doi: 10.4103/IJO.IJO_3017_22.

Higher-order aberrations and visual quality after incision lenticule extraction surgery with intraoperative angle kappa adjustments between small and large kappa patients: A 2-year follow-up

Mengzhen Xie  1   2 , Yingping Deng  1 , Chengshu Sun  1 , Lemei Qiu  1 , Jing Tang  1
Affiliations
Comment

Higher-order aberrations and visual quality after incision lenticule extraction surgery with intraoperative angle kappa adjustments between small and large kappa patients: A 2-year follow-up

Mengzhen Xie et al. Indian J Ophthalmol. 2023 May.

Abstract

Purpose: To evaluate the postoperative visual outcomes, that is, corneal higher-order aberrations (HOAs) and visual quality, of patients with an angle kappa greater than 0.30 mm who underwent angle kappa adjustment during small-incision lenticule extraction (SMILE) 2 years after surgery compared to eyes with an angle kappa less than 0.30 mm.

Methods: This was a retrospective study and included 12 patients from October 2019 to December 2019 who underwent the SMILE procedure for correction of myopia and myopic astigmatism and had one eye with a large kappa angle and another eye with a small kappa angle. Twenty-four months after surgery, an optical quality analysis system (OQAS II; Visiometrics, Terrassa, Spain) was used to measure the modulation transfer function cutoff frequency (MTFcutoff), Strehl2D ratio, and objective scatter index (OSI). HOAs were measured with a Tracey iTrace Visual Function Analyzer (Tracey version 6.1.0; Tracey Technologies, Houston, TX, USA). Assessment of subjective visual quality was achieved using the quality of vision (QOV) questionnaire.

Results: At 24 months postoperatively, the mean spherical equivalent (SE) refraction was - 0.32 ± 0.40 and - 0.31 ± 0.35 in the S-kappa group (kappa <0.3 mm) and the L-kappa group (kappa ≥0.3 mm), respectively (P > 0.05). The mean OSI was 0.73 ± 0.32 and 0.81 ± 0.47, respectively (P > 0.05). There was no significant difference in MTFcutoff and Strehl2D ratio between the two groups (P > 0.05). Total HOA, coma, spherical, trefoil, and secondary astigmatism were not significantly different (P > 0.05) between the two groups.

Conclusion: Adjustment of angle kappa during SMILE helps reduce the decentration, results in less HOAs, and promotes visual quality. It provides a reliable method to optimize the treatment concentration in SMILE.

Keywords: Ablation center; HOAs; angle of kappa; small-incision lenticule extraction (SMILE); visual quality; wavefront aberration.

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Conflict of interest statement

None

Figures

Figure 1
Figure 1
The method to offset the angle of kappa during SMILE. SMILE = small-incision lenticule extraction
Figure 2
Figure 2
Visual outcomes with angle kappa adjustment during SMILE:(a)Uncorrected distance visual acuity (UDVA) outcomes;(b)change in corrected distance visual acuity (CDVA);(c)distribution of achieved spherical equivalent outcomes;(d)spherical equivalent refractive accuracy;(e)refractive astigmatism, and (f) stability of spherical equivalent refraction at 24 months postoperatively; D = diopters
Figure 3
Figure 3
Subjective visual quality of patients 2 years after surgery
See this image and copyright information in PMC

Comment on

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