Metamorphosia and Optical Coherence Tomography

Abstract

I read with interest the article by Watanabe et al.1Watanabe A. Arimoto S. Nishi O. Correlation between metamorphosia and epiretinal membrane optical coherence tomography findings.Ophthalmology. 2009; 116: 1788-1793Abstract Full Text Full Text PDF PubMed Scopus (111) Google Scholar describing the correlation between metamorphopsia and epiretinal membrane (ERM) optical coherence tomography (OCT) findings. The authors concluded that metamorphosia induced by ERM may be related to the edematous areas of the inner nuclear layer detected with spectral-domain OCT. Although the study is well-designed, I have the following comments and questions.For measurement of the thickness of the inner retinal layer, the authors examined 5 horizontal B-scan cross-sections on 3D OCT, and vague points vertically, which were described by the authors as follows: “as many points as possible on each of the horizontal B-scan cross-sections.” Although the authors commented on this point as a limitation of the study, a more precise parameter for statistical comparison between groups should be used. In addition, no comments were included in the article to address prevention of selection bias when the authors measured the thickness by manual caliper.I am wondering how to match the Amsler chart findings with the OCT mapping; and I suggest that the authors explain more precisely the definition of the area correlating to metamorphosia, which was a very important factor in their statistical results. Furthermore, in a case of broad metamorphosia (see Fig 2, Case 3 in this article1Watanabe A. Arimoto S. Nishi O. Correlation between metamorphosia and epiretinal membrane optical coherence tomography findings.Ophthalmology. 2009; 116: 1788-1793Abstract Full Text Full Text PDF PubMed Scopus (111) Google Scholar), measurement of the thickness of the inner nuclear layer, outer plexiform layer, and outer nuclear layer by caliper seems very difficult.I agree that establishment of an objective method for detection of metamorphosia is clinically important and that spectral-domain OCT is useful for detection of objective changes in the inner retinal layers. Furthermore, from the aspect of surgical indication and prognosis, the author's morphological classification of ERM seems to be a good approach. However, I recommend the authors present simpler and more reliable methods for clinical application of their findings. I read with interest the article by Watanabe et al.1Watanabe A. Arimoto S. Nishi O. Correlation between metamorphosia and epiretinal membrane optical coherence tomography findings.Ophthalmology. 2009; 116: 1788-1793Abstract Full Text Full Text PDF PubMed Scopus (111) Google Scholar describing the correlation between metamorphopsia and epiretinal membrane (ERM) optical coherence tomography (OCT) findings. The authors concluded that metamorphosia induced by ERM may be related to the edematous areas of the inner nuclear layer detected with spectral-domain OCT. Although the study is well-designed, I have the following comments and questions. For measurement of the thickness of the inner retinal layer, the authors examined 5 horizontal B-scan cross-sections on 3D OCT, and vague points vertically, which were described by the authors as follows: “as many points as possible on each of the horizontal B-scan cross-sections.” Although the authors commented on this point as a limitation of the study, a more precise parameter for statistical comparison between groups should be used. In addition, no comments were included in the article to address prevention of selection bias when the authors measured the thickness by manual caliper. I am wondering how to match the Amsler chart findings with the OCT mapping; and I suggest that the authors explain more precisely the definition of the area correlating to metamorphosia, which was a very important factor in their statistical results. Furthermore, in a case of broad metamorphosia (see Fig 2, Case 3 in this article1Watanabe A. Arimoto S. Nishi O. Correlation between metamorphosia and epiretinal membrane optical coherence tomography findings.Ophthalmology. 2009; 116: 1788-1793Abstract Full Text Full Text PDF PubMed Scopus (111) Google Scholar), measurement of the thickness of the inner nuclear layer, outer plexiform layer, and outer nuclear layer by caliper seems very difficult. I agree that establishment of an objective method for detection of metamorphosia is clinically important and that spectral-domain OCT is useful for detection of objective changes in the inner retinal layers. Furthermore, from the aspect of surgical indication and prognosis, the author's morphological classification of ERM seems to be a good approach. However, I recommend the authors present simpler and more reliable methods for clinical application of their findings. Correlation between Metamorphopsia and Epiretinal Membrane Optical Coherence Tomography FindingsOphthalmologyVol. 116Issue 9PreviewTo examine the retinal morphologic features of metamorphopsia caused by epiretinal membrane (ERM) and to determine whether spectral-domain optical coherence tomography (SD-OCT) correlated with metamorphopsia. Full-Text PDF Author replyOphthalmologyVol. 117Issue 8PreviewWe thank Dr. Park for his interest in our manuscript.1 As he pointed out, a more precise and selection bias-free parameter to represent thickness of the inner retinal layer should be employed for statistical comparison. Full-Text PDF