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. 2023 Jul 7;12(13):4536.
doi: 10.3390/jcm12134536.

Prediction of Posterior-to-Anterior Corneal Curvature Radii Ratio in Myopic Patients after LASIK, SMILE, and PRK Using Multivariate Regression Analysis

David S Cha  1 , Majid Moshirfar  2   3   4 , Michael S Herron  5 , Jordan M Santos  6 , Phillip C Hoopes  2
Affiliations

Prediction of Posterior-to-Anterior Corneal Curvature Radii Ratio in Myopic Patients after LASIK, SMILE, and PRK Using Multivariate Regression Analysis

David S Cha et al. J Clin Med. .

Abstract

The ratio of posterior-to-anterior curvature radii of the cornea (P/A ratio) is an important element in determining corneal refractive power. P/A ratio has been well studied in patients prior to undergoing refractive surgery, but its postoperative value remains less so. We aimed to examine the value of preoperative characteristics of refractive surgery patients in predicting the 1-year postoperative P/A ratio in LASIK, PRK, and SMILE using both linear and multivariate regression analyses. This was a retrospective study that included patients with manifest refraction spherical equivalents (MRSE) from -7.71D to -0.25D. In total, 164 eyes underwent LASIK, 183 underwent PRK, and 46 underwent SMILE. All patients had preoperative and 1-year postoperative front sagittal and back sagittal keratometry measurements at 4, 5, and 6 mm around the corneal vertex. Postoperative P/A after LASIK, PRK, and SMILE was found to be significantly correlated with MRSE and preoperative P/A. Stepwise variable selection in multivariate regression revealed that spherical equivalent was the most significant predictor of postoperative P/A. When coupled with other preoperative characteristics, including P/A, age, asphericity, and keratometry, the multivariate regressions were able to produce models with high predictive value in LASIK (adjusted R2: 0.957), PRK (adjusted R2: 0.934), and SMILE (adjusted R2: 0.894).

Keywords: asphericity; cornea; keratometry; posterior-to-anterior corneal radii ratio; refractive surgery.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure A1
Figure A1
Scattergram showing correlation between age and postoperative P/A at 6-mm zone after LASIK, SMILE, and PRK.
Figure A2
Figure A2
Scattergram showing correlation between MRSE and postoperative P/A at 6-mm zone after LASIK, SMILE, and PRK.
Figure A3
Figure A3
Scattergram between preoperative cylinder and postoperative P/A at 6-mm zone after LASIK, SMILE, and PRK.
Figure A4
Figure A4
Scattergram showing correlation between preoperative and postoperative P/A at 6-mm zone after LASIK, SMILE, and PRK.
Figure A5
Figure A5
Scattergram showing correlation between anterior asphericity (Q) and postoperative P/A at 6-mm zone after LASIK, SMILE, and PRK.
Figure A6
Figure A6
Scattergram showing correlation between preoperative posterior asphericity (Q) and postoperative P/A at 6-mm zone after LASIK, SMILE, and PRK.
Figure A7
Figure A7
Scattergram showing correlation between preoperative pachymetry and postoperative P/A at 6-mm zone after LASIK, SMILE, and PRK.
Figure A8
Figure A8
Residual plots of multivariate regression analyses of postoperative P/A in LASIK patients at 6-mm zone.
Figure A9
Figure A9
Residual plots of multivariate regression analyses of postoperative P/A in PRK patients at 6-mm zone.
Figure A10
Figure A10
Residual plots of multivariate regression analyses of postoperative P/A in SMILE patients at 6-mm zone.
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References

    1. Norrby S. Sources of error in intraocular lens power calculation. J. Cataract Refract. Surg. 2008;34:368–376. doi: 10.1016/j.jcrs.2007.10.031. - DOI - PubMed
    1. de Sanctis U., Loiacono C., Richiardi L., Turco D., Mutani B., Grignolo F.M. Sensitivity and specificity of posterior corneal elevation measured by Pentacam in discriminating keratoconus/subclinical keratoconus. Ophthalmology. 2008;115:1534–1539. doi: 10.1016/j.ophtha.2008.02.020. - DOI - PubMed
    1. Moshirfar M., Brown T.W., Heiland M.B., Rosen D.B., Ronquillo Y.C., Hoopes P.C. Comparative Analysis of LASIK Flap Diameter and its Centration Using Two Different Femtosecond Lasers. Med. Hypothesis Discov. Innov. Ophthalmol. 2019;8:241–249. - PMC - PubMed
    1. Mifflin M.D., Betts B.S., Frederick P.A., Feuerman J.M., Fenzl C.R., Moshirfar M., Zaugg B. Efficacy and safety of a 3-month loteprednol etabonate 0.5% gel taper for routine prophylaxis after photorefractive keratectomy compared to a 3-month prednisolone acetate 1% and fluorometholone 0.1% taper. Clin. Ophthalmol. 2017;11:1113–1118. doi: 10.2147/OPTH.S138272. - DOI - PMC - PubMed
    1. Payne C.J., Webster C.R., Moshirfar M., Handlon J.J., Ronquillo Y.C., Hoopes P.C. One-Year Visual Outcomes and Corneal Higher-Order Aberration Assessment of Small-Incision Lenticule Extraction for the Treatment of Myopia and Myopic Astigmatism. J. Clin. Med. 2022;11:6294. doi: 10.3390/jcm11216294. - DOI - PMC - PubMed

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