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Table 4 Two-way ANOVA with tests of between-subjects effects for all variables tested, estimated marginal means and pairwise comparison for the IOP dependent variable and intergroup t-test comparison between Preserflo Microshunt with MMC 0.2 mg/ml and Preserflo Microshunt with MMC 0.2 mg/ml and Ologen implantation

From: Preliminary results of Preserflo Microshunt versus Preserflo Microshunt and Ologen implantation

Two-way ANOVA
Levene’s test for equality of error variances
F DF 1 DF 2 P
3.9319 11 271 < 0.001
Tests of between-subjects effects (all variables)
Source Sum of squares DF Mean square F Partial eta squared Observed powerb P
Follow up 9514.47 5 1902.89 98.70 0.639 1.0 < 0.001
Intervention 36.31 1 36.31 1.88 0.06 0.27 0.17
Follow up*Intervention 64.22 5 12.84 0.66 0.01 0.25 0.64
Residual 5224.34 271 19.27     
Estimated marginal means (IOP dependent)
Follow up n Mean Std. Error 95% Confidence interval
Baseline 50 24.78 0.62 23.54 to 26.01
1 Day 50 7.37 0.62 6.13 to 8.60
2 Weeks 50 9.48 0.62 8.24 to 10.71
1 Month 50 10.12 0.62 8.89 to 11.36
3 Months 50 10.98 0.62 9.74 to 12.21
6 Months 50 12.18 0.71 10.78 to 13.58
Follow up Intervention n Mean ± SD Std. Error t-test (P) 95% Confidence interval
Baseline Group A 25 23.52 ± 5.88 0.87 0.26 21.79 to 25.24
  Group B 25 26.04 ± 8.76 0.89 24.27 to 27.80
1 Day Group A 25 7.24 ± 3.47 0.87 0.76 5.51 to 8.96
  Group B 25 7.50 ± 4.23 0.89 5.73 to 9.26
2 Weeks Group A 25 8.88 ± 3.08 0.87 0.34 7.15 to 10.60
  Group B 25 10.08 ± 5.48 0.89 8.31 to 11.84
1 Month Group A 25 9.92 ± 3.25 0.87 0.49 8.19 to 11.64
  Group B 25 10.33 ± 2.53 0.89 8.56 to 12.09
3 Months Group A 25 11.20 ± 2.71 0.89 0.63 9.44 to 12.97
  Group B 25 10.76 ± 2.78 0.87 9.03 to 12.48
6 Months Group A 25 12.00 ± 3.13 0.63 0.89 10.01 to 13.98
  Group B 25 12.36 ± 3.37 0.67 10.38 to 14.35
Pairwise comparisons (IOP dependent) Mean difference Std. Error P a 95% CI a
Baseline 1 Day 17.41 0.88 < 0.0001 14.78 to 20.03
  2 Weeks 15.29 0.88 < 0.0001 12.67 to 17.92
  1 Month 14.65 0.88 < 0.0001 12.02 to 17.28
  3 Months 13.79 0.88 < 0.0001 11.16 to 16.42
  6 Months 12.59 0.94 < 0.0001 9.78 to 15.40
1 Day Baseline −17.41 0.88 < 0.0001 −20.03 to −14.78
  2 Weeks −2.11 0.88 0.27 −4.73 to 0.51
  1 Month −2.75 0.88 0.0314 −5.38 to −0.12
  3 Months −3.61 0.88 0.0009 −6.24 to −0.98
  6 Months −4.81 0.94 < 0.0001 −7.62 to −2.00
Pairwise comparisons (IOP dependent) Mean difference Std. Error P a 95% CI a
2 Weeks Baseline −15.29 0.88 < 0.0001 − 17.92 to −12.67
  1 Day 2.11 0.88 0.27 − 0.51 to 4.73
  1 Month −0.64 0.88 1.00 −3.27 to 1.98
  3 Months −1.50 0.88 1.00 −4.13 to 1.12
  6 Months −2.70 0.94 0.07 −5.51 to 0.10
1 Month Baseline −14.65 0.88 < 0.0001 −17.28 to −12.02
  1 Day 2.75 0.88 0.0314 0.12 to 5.38
  2 Weeks 0.64 0.88 1.00 −1.98 to 3.27
  3 Months −0.85 0.88 1.00 −3.48 to 1.77
  6 Months −2.05 0.94 0.46 −4.86 to 0.75
3 Months Baseline −13.79 0.88 < 0.0001 −16.42 to −11.16
  1 Day 3.61 0.88 0.0009 0.98 to 6.24
  2 Weeks 1.50 0.88 1.00 −1.12 to 4.13
  1 Month 0.85 0.88 1.00 −1.77 to 3.48
  6 Months −1.20 0.94 1.00 −4.01 to 1.61
6 Months Baseline −12.59 0.94 < 0.0001 −15.40 to −9.78
  1 Day 4.81 0.94 < 0.0001 2.00 to 7.62
  2 Week 2.70 0.94 0.07 −0.10 to 5.51
  1 Month 2.05 0.94 0.46 −0.75 to 4.86
  3 Months 1.20 0.94 1.00 −1.61 to 4.01
  1. a Bonferroni corrected
  2. b Computed using alpha = 0.05
  3. Group A: Preserflo Microshunt with MMC 0.2 mg/ml
  4. Group B: Preserflo Microshunt with MMC 0.2 mg/ml and Ologen
  5. SD: standard deviation; DF: degrees of freedom; Eta: eta coefficient (An eta coefficient test is a method for determining the strength of association between a categorical variable)