Changes in metamorphopsia in daily life after successful epiretinal membrane surgery and correlation with M-CHARTS score

Figures & data

Figure 1 Self-administered questionnaire used in the study.

Notes: Questions 1 and 2 were asked at each visit, and Question 3 was asked only at 12 months after the surgery.

Figure 2 Method of determining the metamorphopsia score using M-CHARTS.

Notes: The minimum angle of the dots that appeared straight was taken to be the metamorphopsia score. In this case, metamorphopsia for vertical lines (MV) is 0.4.

Table 1 A contingency table of diagnostic tests

Test	Disease		Total
	Present	Absent
Positive	TP	FP	TP + FP
Negative	FN	TN	FN + TN
Total	TP + FN	FP + TN

Notes: “Disease” in this study corresponds to the presence of an improvement or worsening in the degree of metamorphopsia in daily life after epiretinal membrane surgery.

Abbreviations: TP, true positive response; FN, false negative response; FP, false positive response; TN, true negative response.

Table 2 Examples of concerning explanation variables

	MH	logMH	MV	logMV
Baseline	1.5	0.176	1.0	0
12 months	0.5	−0.301	0.8	−0.096
Change	−1.0	−0.477	−0.2	−0.096
	MHpost-MHpre	logMHpost-logMHpre	MVpost-MVpre	logMHpost-logMHpre

Notes: When the MH score and the MV score were 1.5 and 1.0 at baseline, and 0.5 and 0.8 at 12 months after the surgery respectively, M1-value was −1.0 and M2-value was −0.477. M1-value = either (MH_post-MH_pre) or (MV_post-MV_pre) whichever of these absolute value was larger was used. M2-value = either (logMH_post-logMH_pre) or (logMV_post-logMV_pre) whichever of these absolute value was larger was used.

Abbreviations: MH, metamorphopsia for horizontal lines; MV, metamorphopsia for vertical lines; logMV, logarithm of MV score; logMH, logarithm of MH score.

Table 3 Baseline demographic data of patients with ERM in Part 1 and Part 2

	Part 1	Part 2 (test)	P-value
Sex	42 women/23 men	27 women/29 men	0.102
Age (yrs), mean ± SE (range)	68.8±1.0 (51–84)	69.3±1.1 (53–91)	0.729
Preoperative BCVA (logMAR), mean ± SE	0.33±0.03	0.40±0.03	0.901
Preoperative MH, mean ± SE	1.05±0.08	0.88±0.06	0.245
Preoperative MV, mean ± SE	0.89±0.07	0.74±0.05	0.282

Abbreviations: ERM, epiretinal membrane; SE, standard error; MH, metamorphopsia for horizontal lines; MV, metamorphopsia for vertical lines; yrs, years; BCVA, best-corrected visual acuity; logMAR, logarithm of the minimum angle of resolution.

Figure 3 Changes in the percentage of patients without metamorphopsia and the mean metamorphopsia scores.

Notes: The percentage of patients without metamorphopsia increased as the metamorphopsia scores decreased until finally 35.4% of patients had no metamorphopsia in their daily life at 12 months. Error bars indicate standard error. ^*,†Statistically significant compared with the metamorphopsia score at baseline (P<0.001), n=65.
Abbreviations: MV, metamorphopsia for vertical lines; MH, metamorphopsia for horizontal lines.

Figure 4 ROC curve for six variables to predict the change in the metamorphopsia in daily life.

Notes: The ROC curve with the largest AUC was obtained for the M2-value. M1 = either (MH_post-MH_pre) or (MV_post-MV_pre), whichever of these absolute values was larger was used. M2-value = either (logMH_post-logMH_pre) or (logMV_post-logMV_pre), whichever of these absolute value was larger was used.
Abbreviations: ROC, receiver operating characteristic; AUC, area under the ROC curve; logMV, logarithm of MV score; logMH, logarithm of MH score; MV, metamorphopsia for vertical lines; MH, metamorphopsia for horizontal lines.

Table 4 Comparison of AUC for six variables

	AUC (95% CI)	Optimal cutoff value	P1*	P2†
M2-value	0.936 (0.877–0.994)	<−0.375	<0.0001
logMHpost-logMHpre	0.899 (0.824–973)	<−0.228	<0.0001	0.329
logMVpost-logMVpre	0.881 (0.790–0.971)	<−0.165	<0.0001	0.136
MVpost-MVpre	0.852 (0.733–0.972)	<−0.250	<0.0001	0.095
M1-value	0.842 (0.693–0.991)	<−0.250	<0.0001	0.170
MHpost-MHpre	0.831 (0.705–0.957)	<−0.350	<0.0001	0.117

Notes: The receiver operating characteristic (ROC) curve with the largest AUC was obtained for the M2-value.

* Comparison with diagonal.

† Pairwise comparison with the ROC curve for M2-value. M1 = either (MH_post-MH_pre) or (MV_post-MV_pre), whichever of these absolute values was larger was used. M2-value = either (logMH_post-logMH_pre) or (logMV_post-logMV_pre), whichever of these absolute value was larger was used.

Abbreviations: AUC, area under the ROC curve; MH, metamorphopsia for horizontal lines; MV, metamorphopsia for vertical lines; logMV, logarithm of MV score; logMH, logarithm of MH score; CI, confidence interval.

Table 5 Reproducibility of M-CHARTS scores

	MH	logMH	MV	logMV
Test (mean ± SD)	0.888±0.493	−0.126±0.269	0.751±0.431	−0.195±0.254
Retest (mean ± SD)	0.898±0.494	−0.114±0.248	0.7599±0.443	−0.186±0.241
Difference (mean ± SD)	0.01±0.255	0.012±0.138	−0.182±0.241	0.009±0.127
Reproducibility (minimum/maximum)	−0.491/0.510	−0.260/0.284	−0.402/0.417	−0.240/0.258

Notes: Reproducibility of each M-CHARTS score was calculated as the mean difference (±1.96 SD of the difference) between test and retest measurements. Reproducibility of logMET scores (logMH and logMV) are within ±0.3.

Abbreviations: MH, metamorphopsia for horizontal lines; MV, metamorphopsia for vertical lines; SD, standard deviation; logMV, logarithm of MV score; logMH, logarithm of MH score; logMET, logarithm of metamorphopsia.