Table 2.

Item Parameter Estimates and Fit Statistics

Item	Item location	Infit MNSQ	Outfit MNSQ	Polyserial item-test correlation
1. Problem climbing stairs	−0.49	0.90	0.63	0.59
2. Problem making out bumps	0.14	0.87	0.76	0.69
3. Problem seeing animals or vehicles	−0.15	0.77	0.56	0.66
4. Problem recognizing faces	−0.27	0.97	0.69	0.58
5. Problem seeing outside in bright light	1.20	1.00	0.94	0.75
6. Frightened to go out	−1.00	0.99	1.06	0.59
7. Enjoy social functions less	−0.37	0.94	0.81	0.55
8. Ashamed can’t see	−0.75	1.06	1.00	0.60
9. Dazzled in bright light	1.38	1.29	1.30	0.70
10. Vision blurred in sunlight	−0.18	0.76	0.69	0.77
11. Bright light hurt eyesa	0.03	1.53	2.32	0.48
12. Blurred vision	0.45	0.87	0.87	0.82

MNSQ mean-square

^aitem removed to form 11-item SF-IND-VFQ