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Corneal power measurements by ray tracing in eyes after small incision lenticule extraction for myopia with a combined Scheimpflug Camera–Placido disk topographer

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Abstract

Purpose

To evaluate the accuracy of the measurements of corneal power obtained by ray tracing with a combined Scheimpflug camera–Placido disk corneal topographer (Sirius) in eyes after small incision lenticule extraction for myopia (SMILE).

Methods

Retrospective cases study includes 50 eyes of 50 patients who underwent myopic SMILE. Mean value of simulated keratometry (Kpost), mean pupil power (MPP) (ray tracing, diameter of the entrance pupil range 3–6 mm), anterior and posterior corneal radius, and corneal thickness were obtained with Sirius topographer preoperatively and three months postoperatively, as well as cycloplegic refraction. True net power, equivalent keratometry readings, and Haigis equivalent power formula were calculated, and these measurements, MPP and Kpost, were compared with the corneal power calculated with the clinical history method (CHM).

Results

Corneal power measurements obtained with all methods were significantly different from CHM (P < 0.001), except the value of MPP obtained at 5.5 mm (P = 0.927). A good direct correlation was found between CHM and all measurements. The distribution of differences as compared with the CHM showed that the lowest difference corresponded to the value of MMP at 5.5 mm (− 0.002 ± 0.6). The Bland–Altman plots for the MPP at 5.5 mm showed 95% limits of agreement between − 1.1787 D and 1.1741 D.

Conclusions

MPP obtained by ray tracing within a diameter of entrance pupil of 5.5 mm could predict corrected corneal power derived from the CHM in eyes following SMILE surgery.

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Funding

The authors certify that no financial support has been received for this research.

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Authors and Affiliations

  1. Victoria de Rojas Instituto Oftalmológico, Policlínica Assistens, A Coruña, Spain

    Mª Victoria de Rojas Silva & Adrián Tobío Ruibal

  2. Department of Ophthalmology, Complexo Hospitalario Universitario, A Coruña, Spain

    Mª Victoria de Rojas Silva

  3. Research Support Unit, Complexo Hospitalario Universitario, A Coruña, Spain

    Jorge Suanzes Hernández

  4. Institute of Biomedical Research (INIBIC), A Coruña, Spain

    Jorge Suanzes Hernández

Authors
  1. Mª Victoria de Rojas Silva
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  2. Adrián Tobío Ruibal
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  3. Jorge Suanzes Hernández
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Correspondence to Mª Victoria de Rojas Silva.

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Conflicts of interest

Mª Victoria de Rojas Silva is a Zeiss consultant, but she certifies that she does not have any financial or non-financial interest in the subject matter or materials discussed in this manuscript. The other authors certify that they do not have any financial or non-financial interest in the subject matter or materials discussed in this manuscript.

Consent to participate

Due to the retrospective nature of the research design, informed consent and institutional review board approval were unnecessary. The data used in the study were managed anonymously as part of the institution´s quality control protocols (Victoria de Rojas Instituto Oftalmológico—Policlínica Assistens).

Ethical approval

All procedures performed involving humans in this study were in accordance with the ethical standards of the institution (Victoria de Rojas Instituto Oftalmológico—Policlínica Assistens) and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

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de Rojas Silva, M.V., Tobío Ruibal, A. & Suanzes Hernández, J. Corneal power measurements by ray tracing in eyes after small incision lenticule extraction for myopia with a combined Scheimpflug Camera–Placido disk topographer. Int Ophthalmol 42, 921–931 (2022). https://doi.org/10.1007/s10792-021-02073-9

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  • DOI: https://doi.org/10.1007/s10792-021-02073-9

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