Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jul;43(7):2493-2501.
doi: 10.1007/s10792-023-02649-7. Epub 2023 Mar 11.

The effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis

Haohan Zou #  1   2 , Xinheng Zhao #  2 , Jiamei Zhang  2 , Lulu Xu  2 , Qian Fan  2 , Lin Zhang  2 , Tommy C Y Chan  3   4 , Yan Wang  5   6
Affiliations

The effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis

Haohan Zou et al. Int Ophthalmol. 2023 Jul.

Abstract

Purpose: To evaluate the effects of different programmed optical zones (POZs) on achieved corneal refractive power (CRP) with myopic astigmatism after small incision lenticule extraction (SMILE).

Methods: In total, 113 patients (113 eyes) were included in this retrospective study. The eyes were divided into two groups according to POZ: group A (6.5, 6.6, and 6.7 mm, n = 59) and group B (6.8, 6.9, and 7.0 mm, n = 54). Fourier vector analysis was applied to evaluate the error values between the attempted and achieved corneal refractive power (CRP). Alpins vector analysis was used to calculate surgically induced astigmatism (SIA), difference vector (DV), magnitude of error (ME), and astigmatism correction index (ACI). Multivariate regression analysis was performed to assess potential factors associated with the error values.

Results: The error values in the group with large POZ were closer to zero, and significantly associated with the POZ at 2 and 4 mm of the cornea (β = - 0.50, 95% confidence interval [CI] [- 0.80, - 0.20]; β = - 0.37, 95% CI [- 0.63, - 0.10], P < 0.05, respectively). For the correction of astigmatism, the values of SIA, ME, and ACI were lower in group B than in group A (P < 0.05). The fitting curves between TIA and SIA were y = 0.83x + 0.19 (R2 = 0.84) and y = 1.05x + 0.04 (R2 = 0.90), respectively.

Conclusions: Smaller POZs resulted in higher error values between the achieved- and attempted-CRP in the SMILE procedure, which should be considered when performing surgery.

Keywords: Corneal refractive power; Myopic astigmatism; Programmed optical zone; Vector analysis.

PubMed Disclaimer

References

    1. Kim TI, Alió del Barrio JL, Wilkins M, Cochener B, Ang M (2019) Refractive surgery. Lancet 393:2085–2098. https://doi.org/10.1016/So140-6736(18)33209-4 - DOI - PubMed
    1. Primavera L, Canto-Cerdan M, Alio JL, del Barrio JLA (2022) Influence of age on small incision lenticule extraction outcomes. Br J Ophthalmol 106:341–348. https://doi.org/10.1136/bjophthalmol-2020-316865 - DOI - PubMed
    1. Liu J, Wang Y (2020) Influence of preoperative keratometry on refractive outcomes for myopia correction with small incision lenticule extraction. J Refract Surg 36:374–379. https://doi.org/10.3928/1081597X-20200513-01 - DOI - PubMed
    1. Torky MA, Alzafiri YA (2017) Visual and refractive outcomes of small-incision lenticule extraction in mild, moderate, and high myopia: six-month results. J Cataract Refract Surg 43:459–465. https://doi.org/10.1016/j.jcrs.2017.01.015 - DOI - PubMed
    1. Shin DH, Lee YW, Song JE, Choi CY (2020) Comparison of refractive outcomes after photorefractive keratectomy with different optical zones using Mel 90 excimer laser. BMC Ophthalmol 20:270. https://doi.org/10.1186/s12886-020-01537-3 - DOI - PubMed - PMC

LinkOut - more resources