Table 1.

Interventional studies assessing the effects of the macular carotenoids on visual performance in normal subjects.

Principal author(s)	Year	n	Placebo-control	Carotenoids	Visual performance tests	Study duration (months)	Observed visual benefit following supplementation
Monjea	1948	14	No	L dipalmitate	Dark adaptation & scotopic VA	2-6	Yes‡
Wustenberga	1951	7	No	L dipalmitate	Dark adaptation	-	No
Klaes & Riegelb	1951	-	No	L dipalmitate	Dark adaptation	-	Yes
Andreani & Volpia	1956	10	No	L dipalmitate	Dark adaptation	-	Yes
Moscia	1956	-	No	L dipalmitate	Light sensitivity	-	Yes
Hayanoa	1959	-	No	L dipalmitate	Dark adaptation	-	Yes†
Wenzelc	2006	10	Yes	30mg L + 2.7mg Z	Photophobia	3	Yes
Rodriguez-Carmonad	2006	24	Yes*	10mg/20mg of L/Z/L+Z	B/Y color discrimination	12	No
Kvansakule	2006	34	Yes	10mg L/10mg Z/combination	Mesopic CS	6	Yes
Bartlett & Eperjesif	2008	29	Yes	6mg L	VA (dist.&near), CS, photostress recovery	18	No
Stringham & Hammondg	2008	40	No	10mg L + 2mg Z	Photostress recovery & grating visibility	6	Yes; both
Nolanh	2010	121	Yes	12mg L + 1mg Z	VA, CS, GD, photostress recovery	12	No
Loughmani	2012	36	Yes	10mg L+2mg Z+10mg MZ/20mg L+2mg Z	VA, CS, GD, photostress recovery	6	Yes; VA, CS, GD
Yaoj	2013	120	Yes	20mg L	VA, CS, GD	12	Yes

Abbreviations: carotenoids=macular carotenoids investigated; L=lutein; VA=visual acuity; Z=zeaxanthin; B/Y=blue/yellow; CS=contrast sensitivity; GD=glare disability; MZ=meso-zeaxanthin; - =data not available.

^a-jdata obtained respectively from published literature (Nussbaum et al., 1981) (Klaes and Riegel, 1951) (Wenzel et al., 2006) (Rodriguez-Carmona et al., 2006) (Kvansakul et al., 2006) (Bartlett and Eperjesi, 2008) (Stringham and Hammond, 2008) (Nolan et al., 2011) (Loughman et al., 2012) (Yao et al., 2013).

^*for second 6 months of the study

^†proportional to serum L

^‡described as having a “transient” benefit