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Purpose To assess the correlations between a patient's subjective perception of metamorphopsia and the clinical measurements of metamorphopsia by M-CHARTS and PreView PHP (PHP). Methods The authors designed a 10-item questionnaire focusing on the symptoms of metamorphopsia and verified its validity with a Rasch analysis. M-CHARTS measured the minimum visual angle of a dotted line needed to detect metamorphopsia, and PHP used the hyperacuity function for detection. Subjects were 39 patients with idiopathic epiretinal membrane (ERM), 22 patients with idiopathic macular hole (M-hole), 19 patients with age-related macular degeneration (AMD), and 51 healthy controls. Results Rasch analysis suggested the elimination of one question. The nine-item questionnaire score significantly correlated to the M-CHARTS score in ERM (r = 0.59; P = 0.0004) but not in M-hole and to the PHP result in AMD (r = -0.29; P = 0.04) but not in ERM. Eighty percent of ERM patients with greater horizontal M-CHARTS score subjectively perceived horizontal metamorphopsia more often. M-CHARTS showed better sensitivities than PHP in both ERM (89% vs. 42%) and AMD (74% vs. 68%) and better specificity (100% vs. 71%) in healthy controls. Rasch analysis indicated that the present form of the questionnaire is better suited for moderate to severe cases of metamorphopsia than for mild cases. Conclusions The questionnaire appears to be a valid assessment of patient subjective perception of metamorphopsia and can be used to supplement the clinical measurements of metamorphopsia by M-CHARTS and PHP in patients with macular diseases.

PURPOSE Using M-CHARTS (Inami Co., Tokyo, Japan), which were developed by the authors to measure metamorphopsia, and image-analysis software, which was developed to quantify retinal contraction, the authors investigated the relationship between the degree of retinal contraction and the degree of metamorphopsia in eyes with idiopathic epiretinal membrane (ERM). METHODS This study was conducted in 29 eyes with ERM (29 patients, 20 women; mean age, 62.1 +/- 8.6 years) observed for at least 3 years (mean, 3.55 +/- 0.6 years) after diagnosis. Horizontal (MH) and vertical (MV) metamorphopsia scores were obtained with the M-CHARTS. Horizontal and vertical retinal contraction due to ERM was measured by using image-analysis software developed by the authors to calculate horizontal and vertical components of changes in the locations of retinal vessels on sequential fundus images. RESULTS There was a significant (P < 0.01) positive correlation between the degree of retinal contraction and metamorphopsia score. In addition, there were significant positive correlations between horizontal contraction of the retina and the MV score (P < 0.01) and between vertical contraction of the retina and the MH score (P < 0.05). No significant correlations were found between change in the metamorphopsia score and change in visual acuity or mean defect. CONCLUSIONS Metamorphopsia scores correlate well with measurements of retinal contraction due to idiopathic ERM. Using M-CHARTS is a simple and useful method for quantitatively monitoring metamorphopsia in patients with ERM.

Purpose To quantify the degree of metamorphopsia in patients with idiopathic epiretinal membranes (ERMs), by use of a new metamorphopsia chart (M-CHARTS) developed by the authors. Methods These M-CHARTS had 19 dotted lines with dot intervals of between 0.2 degrees (fine) and 2.0 degrees (coarse) visual angles. As the dot intervals were changed from fine to coarse, a decrease in the severity of metamorphopsia was noted. In this study, the minimum visual angle of the dotted lines needed to cause the metamorphopsia to disappear was measured in 51 eyes of 51 patients with ERM. The metamorphopsia scores were compared with the stages of ERM classified by scanning laser ophthalmoscope (SLO) images. Results In patients with ERM, the metamorphopsia score increased depending on the severity of membrane proliferation classified by SLO images. The scores obtained from the horizontal dotted lines were larger than those of the vertical lines in advanced stages of ERM. Conclusions M-CHARTS provide a very simple and useful method for evaluating the severity of metamorphopsia in patients with ERM.