Table 8 Overall performance of the NEI VFQ-25
Parametar | NEI VFQ-25 |
|---|---|
Misfitting items (n) | 5 |
Person separation reliability (PSR) | 0.91 |
Person separation index (PSI) | 3.26 |
Principal component analysis (eigenvalue in 1st contrast) | 3.3 |
Valid subscales (n) | 3 |
DIF by age (2 items) | ≤0.61 logits |
DIF by sex (3 items) | ≤0.61 logits |
DIF by systemic comorbidity (1 item) | 0.94 logits |
DIF by better eye visual acuity (5 items) | ≤0.87 logits |