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Abstract

We appreciate the insightful comments of Dr Park and associates on our published article. 1 Kamiya K. Shimizu K. Igarashi A. Kobashi H. Factors influencing long-term regression after posterior chamber phakic intraocular lens implantation for moderate to high myopia. Am J Ophthalmol. 2014; 158: 179-184 Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar We agree with their opinion that the use of measurements from only 1 eye for studies involving eye-specific outcomes is recommended for the statistical analysis because of inter-eye correlation. 2 Karakosta A. Vassilaki M. Plainis S. Elfadl N.H. Tsilimbaris M. Moschandreas J. Choice of analytic approach for eye-specific outcomes: one eye or two?. Am J Ophthalmol. 2012; 153: 571-579 Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar , 3 Armstrong R.A. Statistical guidelines for the analysis of data obtained from one or both eyes. Ophthalmic Physiol Opt. 2013; 33: 7-14 Crossref PubMed Scopus (247) Google Scholar Otherwise, the model-based analysis such as mixed model is useful when both eyes from 1 patient are included. We examined 60 eyes of 35 consecutive patients undergoing posterior chamber phakic intraocular lens implantation in the current study, in accordance with many published studies on refractive surgery. However, even when we included 35 eyes of 35 patients, we obtained similar results that the explanatory variables relevant to the myopic regression were the preoperative axial length and patient age. Moreover, the normality of all data samples was first checked by the Kolmogorov-Smirnov test. Since the data did not fulfill the criteria for normal distribution, the Spearman correlation coefficient was used to assess the univariate relationship of myopic regression with other variables in the present study. Even when the Pearson correlation coefficient was used for statistical analysis, we obtained almost similar results that there were significant correlations of myopic regression with the preoperative axial length and patient age, and no significant correlation shown with other clinical factors. Accordingly, we believe that eyes of older patients and eyes with greater axial length showed greater long-term myopic shift after posterior chamber phakic intraocular lens implantation. Factors Influencing Long-Term Regression After Posterior Chamber Phakic Intraocular Lens Implantation for Moderate to High MyopiaAmerican Journal of OphthalmologyVol. 158Issue 6PreviewWe have read with great interest the article by Kamiya and associates.1 The authors showed that eyes of older patients and eyes with longer axial length were more predisposed to have greater myopic regression after posterior chamber phakic intraocular lens (Visian ICL; STAAR Surgical) implantation. We are confident that the study was well designed, but we have the following comments from a statistical point of view. Full-Text PDF