The medical records of 27 eyes from 27 patients (male/female: 13 eyes/14 eyes (65.3±6.6 years [mean ± standard deviation]; age range 53–81 years) with idiopathic MH were studied. Eight eyes (29.6%) had stage 2 MH, 11 eyes (40.8%) had stage 3 MH, and 8 eyes (29.6%) had stage 4 MH. Twenty-two phakic eyes underwent phacoemulsification and intraocular lens implantation simultaneously with vitrectomy.

The average minimum MH diameter was 263.6±103.5 μm (range 45–495 μm) in the horizontal direction and 250.5±109.4 μm (range 62–443 μm) in the vertical direction, whereas the average basal MH diameter was 660.0±175.9 μm (range 253–899 μm) in the horizontal direction and 610.5±170.1 μm (range 220–855 μm) in the vertical direction. The average horizontal basal MH diameter was significantly greater than the average vertical MH diameter (P < 0.001).

The BCVA was 0.46±0.05 logMAR units preoperatively, unchanged to 0.30±0.05 logMAR units at 2 weeks, and improved to 0.17±0.04 logMAR units at 1 month, 0.10±0.03 logMAR units at 3 months, and 0.04±0.03 logMAR units at 6 months postoperatively (P value range: P < 0.001–0.060).

Pre- and postoperative average M -CHARTS scores

The average preoperative MCV was 0.71±0.10, and 0.47±0.05 at 2 weeks postoperatively (P < 0.001), 0.41±0.06 at 1 month, 0.40±0.06 at 3 months, and 0.37±0.06 at 6 months (P < 0.001). The average preoperative MCH was 0.70±0.13, improved to 0.24±0.05 at 2 weeks, 0.18±0.04 at 1 month, 0.17±0.04 at 3 months and 0.17±0.04 at 6 months postoperatively (all P < 0.001) (Fig. 2).

Figure 2

Time course of M-CHARTS scores. The average vertical M-CHARTS score improved significantly at 2 weeks and 6 months postoperatively. The average horizontal M-CHARTS score improved at all postoperative time points (all P < 0.001). Solid line; MCV: vertical M-CHARTS score. Dotted line; MCH: horizontal M-CHARTS score. Repeated measures ANOVA was used for comparisons. Significant P values are indicated by asterisks (*).

Pre- and postoperative average retinal distances

The average preoperative near-vertical retinal distance was 1003.8±38.2 μm and decreased to 715.5±36.0 μm at 2 weeks, 763.5±36.4 μm at 1 month, 763.5±24.5 μm at 3 months, and 776.46±29.8 μm at 6 months. The average preoperative near-horizontal retinal distance was 994.0±29.5 μm, which decreased to 796.0±33.2 μm at 2 weeks, 823.0±40.5 μm at 1 month, 826.9±31.3 μm at 3 months and 848.5±40.3 μm at 6 months. The average preoperative far-vertical retinal distance was 2806.8±29.5μm and decreased to 2442.0±72.7 μm at 2 weeks, 2637.3±32.6 μm at 1 month, 2652.3±30.9 μm at 3 months, and 2588.0±57.4 μm at 6 months. The average preoperative far-horizontal retinal distance was 2602.4±44.7 μm, which decreased to 2443.0±3.6.5 μm at 2 weeks, 2476.1±43.1 μm at 1 month, 2430.4±43.9 μm at 3 months and 2478.2±38.6.9 μm at 6 months (all P < 0.001). The time course of the average retinal distance is shown in Fig. 3.

Figure 3

The time course of the retinal distance. Both vertical and horizontal near and far retinal distances were significantly decreased at all visits (all P < 0.001). Solid line; NV: near-vertical retinal distance. Dotted line; NH: near-horizontal retinal distance. Broken line; FV: far-vertical retinal distance. Thick line; FH: far-horizontal retinal distance. Repeated measures ANOVA was used for comparisons. Significant P values are indicated by asterisks (*).

Correlations of M-CHARTS scores with the size of macular hole

Preoperative MCH and MCV and those at 6 months did not correlate with minimum and basal MH diameters in any direction, nor did changes in MCH and MCV at 6 months correlate with any MH diameter (rs=−0.107 to 0.251, all P values > 0.05).

Correlations of M-CHARTS scores with retinal displacement%

Preoperative MCH and MCV did not correlate with the retinal displacement% at any visit, and MCH and MCV at 6 months and their changes also did not correlate with the retinal displacement% (all P values > 0.05).

Comparison of retinal displacement%

Retinal displacement% was significantly greater in the near region than in the far region at all visits (P < 0.001) (Table 1). The vertical retinal displacement% was significantly greater than the horizontal retinal displacement% at 2 weeks, 3 and 6 months in the near region (P = 0.008–0.025) and at 2 weeks in the far region (P = 0.041).

Table 1 Comparison of retinal displacement% in near and far regionsCorrelations of retinal displacement% with basal MH diameter

FV% at 2 weeks correlated with horizontal basal MH diameter. NV% and NH% at 2 weeks and 1 month were correlated with horizontal and vertical basal MH diameters. NH% at 6 months correlated with horizontal and vertical basal MH diameters (Table 2).

Table 2 Correlations of retinal displacement% with basal MH diameter.Multivariate analysis for the M-CHARTS score

Multiple regression analysis was performed to identify a factor that is most relevant to the M-CHARTS scores among the MH diameter, changes in retinal thickness, and retinal displacement%. The objective variables were defined as the MCH and MCV at baseline and 6 months postoperatively, and the explanatory variables were defined as the INL% and OR%, retinal displacement% in near and far regions, and basal MH diameter. For analyses in which the objective variable was the vertical M-CHARTS score, the nasal and temporal rates of change in retinal thickness and horizontal retinal displacement% were selected as the explanatory variables.

As shown in Tables 3 and 4, horizontal MH diameter was a factor most related to the MCV at baseline and at 6 months (P value range: P = 0.002–0.004). In other words, the larger the horizontal MH diameter, the greater the degree of vertical metamorphopsia before and after surgery.

Table 3 Multivariate regression analysis for MCV score at baseline.Table 4 Multivariate regression analysis for MCV at 6 months postoperatively.

As shown in Table 5, inferior OR% and NV% at 6 months were factors most related to MCH at 6 months (P < 0.001). In other words, the thinner the inferior OR thickness postoperatively and the greater the retinal displacement near the center of the macula, the greater the degree of horizontal metamorphopsia at 6 months postoperatively.

Table 5 Multivariate regression analysis for MCH at 6 months postoperatively.

There were no significant factors for changes in the M-CHARTS score at 6 months (all P values > 0.05).