CLEAR 2013.

Methods	Parallel group RCT Method of allocation: coded tablets prepared by manufacturer Masking: participant ‐ yes; provider ‐ yes; outcome ‐ yes Loss to follow‐up: 13%
Participants	Country: The Netherlands and the UK Number of people randomised: 84 (84 eyes) Number (%) of people followed up: 73 (87%) (73 eyes) Average age (range): 71 years (unknown) Percentage women: 61% (56% in intervention group, 67% in control group) Ethnic group: unknown Baseline visual acuity: average 0.1 logMAR in intervention group, and 0.05 logMAR in control group Comorbidities affecting the eye: unknown Percentage current smokers: unknown Inclusion criteria: 50 to 80 years AMD grade 0 to 4 in one eye (Rotterdam grading) best corrected visual acuity (BCVA) of logMAR 0.5 or better minimal cataract Exclusion criteria: any ophthalmic disorder, such as diabetic retinopathy; optic atrophy; pigmentary abnormalities considered by the investigating ophthalmologist to be less typical of AMD than of some other condition (e.g. myopia) history of glaucoma any dietary supplements containing lutein, zeaxanthin, or meso‐zeaxanthin within 3 months of the start of the study unable to understand the study procedures or unable to give informed consent
Interventions	Intervention: lutein 10 mg (daily) 42 people randomised (42 eyes) 36 (86%) people followed up (36 eyes) Comparator: placebo soya bean oil (daily) 42 people randomised (42 eyes) 37 (88%) people followed up (37 eyes) Duration: 12 months Similarity between intervention and comparator: Quote: "The [..] capsules and their packaging were completely indistinguishable"
Outcomes	Primary: not described in paper but main aim was to investigate effects on MPOD and VA Secondary: not described in paper Quote: "Other measurements conducted as part of the study were scanning laser ophthalmoscope (SLO)–based MPOD, retinal reflectometry–based MPOD, dark adaptometry, optical coherence tomography (OCT), and ocular scatter. These data will be described in separate reports." From clinical trials registry entry (but not prospectively registered): Primary Outcome Measures: Macular Pigment Optical Density (time frame: baseline, 4 months, 8 months, 12 months; designated as safety issue: No) Secondary Outcome Measures: Visual Acuity (time frame: baseline, 4 months, 8 months, 12 months; designated as safety issue: No) Follow‐up: 3, 8, and 12 months Eyes: one eye per person, unclear how selected. Quote: "According to the inclusion criteria, a ‘test eye’ was allocated to each patient and data from only this eye were analyzed".
Notes	Source of funding: Quote: "Supported partly by BASF, the UK Medical Research Council, the Manchester Biomedical Research Centre, and the Greater Manchester Comprehensive Local Research Network." Declaration of interest: All authors reported no declaration of interest Date study conducted August 2007 to August 2009 (from clinical trials registry entry) Trial registration number: NCT01042860 (registered retrospectively)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "A randomization code was generated by the sample manufacturer. Treatment numbers were allocated in ascending order using the next available consecutive number and capsules distributed accordingly." Judgement comment: Unclear how code was generated, but we have assumed it was unpredictable.
Allocation concealment (selection bias)	Low risk	Quote: "The P and L capsules and their packaging were completely indistinguishable. The code remained with the manufacturer until the end of the intervention trial. The experimenters were unaware of which patients were assigned to which groups."
Blinding of participants and personnel (performance bias) Visual acuity	Low risk	Quote: "The P and L capsules and their packaging were completely indistinguishable. The code remained with the manufacturer until the end of the intervention trial. The experimenters were unaware of which patients were assigned to which groups"
Blinding of participants and personnel (performance bias) Progression AMD	Low risk	Quote: "The P and L capsules and their packaging were completely indistinguishable. The code remained with the manufacturer until the end of the intervention trial. The experimenters were unaware of which patients were assigned to which groups"
Blinding of outcome assessment (detection bias) Visual acuity	Low risk	Quote: "The P and L capsules and their packaging were completely indistinguishable. The code remained with the manufacturer until the end of the intervention trial. The experimenters were unaware of which patients were assigned to which groups"
Blinding of outcome assessment (detection bias) Progression AMD	Low risk	Quote: "The P and L capsules and their packaging were completely indistinguishable. The code remained with the manufacturer until the end of the intervention trial. The experimenters were unaware of which patients were assigned to which groups"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: Follow‐up high and similar between lutein (86%) and placebo groups (88%).
Selective reporting (reporting bias)	Low risk	Judgement comment: Outcomes in trials registry entry were reported.