Table 3

 Internal consistency and test-retest reliability of the IND-VFQ33

ScaleInternal consistency
Inter-item correlation range (mean)Item-total correlation range (mean)Cronbach’s αTest-retest
NoαNor*
*Pearson’s correlation coefficient.
General functioning0.52–0.79 (0.66)0.69–0.86 (0.80)5640.972920.96
Psychosocial impact0.49–0.71 (0.60)0.64–0.76 (0.72)6250.883290.90
Visual symptoms0.37–0.74 (0.51)0.54–0.77 (0.66)6510.883460.92