Psychometric validation of the visual function questionnaire-25 in patients with diabetic macular edema

Table 3 Internal consistency reliability, concurrent validity, and construct validity at baseline

	Internal-consistency reliability	Concurrent validity			Construct validity
		EQ-5D VAS	Study eye: ETDRS total letters	Fellow eye: ETDRS Total letters	Study eye: ETDRS 73–64 letters	Study eye: ETDRS 52–35 letters
VFQ-25 domain	Cronbach’s alpha*	Pearson correlation			Mean ± SD		P value from student’s t-test
1. General Health	N/A	0.43	0.19	0.10	41.0 ± 24.17	33.5 ± 22.07	.078
2. General Vision	N/A	0.30	0.31	0.29	60.3 ± 15.27	46.4 ± 15.95	<.001
3. Ocular Pain	0.70	0.20	0.10	0.01	78.9 ± 23.67	76.1 ± 24.49	.52
4. Near Activities	0.73	0.36	0.35	0.36	65.8 ± 21.93	45.1 ± 21.55	<.001
5. Distance Activities	0.58	0.33	0.34	0.36	70.9 ± 23.44	51.2 ± 23.99	<.001
6. Social Functioning	0.64	0.33	0.31	0.34	84.8 ± 19.51	69.1 ± 27.40	<.001
7. Mental Health	0.78	0.35	0.33	0.30	65.3 ± 24.96	44.8 ± 27.62	<.001
8. Role Difficulties	0.77	0.16	0.27	0.23	59.4 ± 30.67	44.1 ± 26.40	.004
9. Dependency	0.85	0.37	0.34	0.34	78.0 ± 26.40	55.6 ± 33.39	<.001
10. Driving	0.75	0.34	0.41	0.51	65.5 ± 32.09	31.8 ± 33.52	<.001
11. Colour Vision	N/A	0.19	0.18	0.14	87.7 ± 19.16	81.8 ± 24.49	.14
12. Peripheral Vision	N/A	0.19	0.26	0.36	75.4 ± 25.83	61.4 ± 25.14	.003
VFQ-25 Composite	0.92	0.38	0.39	0.40	72.1 ± 17.91	56.1 ± 18.00	<.001

ISSN: 1477-7525