Table 3. Results for visual acuity.

Study	Outcome	Measurement instrument	Result	P-valuea
Berson et al12	Annual rate of decline (letters/year)	Test ETDRS	Vit A group: 1.1	ns (P-value not reported)
			Vit A+E group: 0.7
			Vit E group: 0.9
			Control group: 0.9
Berson et al14	Annual rate of decline (letters/year)b	Test ETDRS	DHA+Vit A group: 0.71±0.12	0.86
			Placebo+Vit A group: 0.68±0.12
Hoffman et al16	Difference on visual acuity 0–4 years (logMAR)b	Test ETDRS	DHA group: 0.05±0.23	0.88
			Placebo group: 0.06±0.2
Hoffman et al9, 10	%Change per year (letters/year)c	Test ETDRS	DHA group: −0.8±0.8 (−2.9)	0.19
			Placebo group: 1.43±1.1 (2.0)
Bahrami et al11	Change in visual acuity (logMAR) (coefficient; 95% CI)	Self-reported by computer test	100% Illumination: −0.0002 (−0.0131; 0.0128)	Normal conditions: 0.981
			4% Illumination: 0.0054 (−0.0137; 0.0246)	Low illumination: 0.578
			0,1% Illumination: −0.0762 (−0.139; −0.0131)	Very low illumination: 0.018
Berson et al13	Annual rate of decline (letters/year)b	Test ETDRS	Lutein group: 0.53±0.12 (n=110)d	0.80
			Control group: 0.49±0.12 (n=111)d
Rotenstreich et al19	Change in letters numberb	Test ETDRS	β-Carotene period: 0.4±0.9 (P=0.70)	0.90
			Placebo period: 0.15±0.9 (P=0.90)
Lee et al18	Change in visual acuity	Test ETDRS	Not reported	ns (P-value not reported)

Abbreviations: CI, confidence interval; DHA, docosahexaenoic acid; ETDRS: Early Treatment Diabetic Retinopathy Study; ns, no significant; Vit, vitamin.

^aDifference between groups/periods.

^bmean±SD.

^cmean±SE.

^dN analysed.