Möller 1994.

Methods	Parallel‐group RCT
Participants	149 participants with seasonal allergic conjunctivitis
Interventions	Two treatment arms: nedocromil sodium; placebo. Duration of treatment 4 weeks
Outcomes	Investigator's and participants' (or their parents') assessment of severity of symptoms. Mean score of itching, redness, soreness, grittiness, photophobia, and general eye condition (using a 5‐point scale; 0 = none, 4 = very severe) Time points: during peak pollen in the 4 weeks of treatment
Country	Sweden
Number randomised, gender (male:female)	149 participants randomised, 146 participants analysed. M:F 92:57
Age mean (SD), median, range	Mean (range): nedocromil sodium 12 years (6‐16); placebo 13 years (6‐16)
Notes	Not reported when study was conducted. Source of funding: Fisons Pharmaceuticals. Declaration of interest by the authors was not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Use of predetermined randomised code (p.885 ‐ patients and methods): "Patients were then allocated, by a predetermined randomised code... Trial supplies were coded at source, by computer‐generated numbers randomised in a balanced blocks of four".
Allocation concealment (selection bias)	Low risk	Conceal allocation described (p.885 ‐ patients and methods): "Patients entering the trial were assigned to treatment numbers in sequence. The codes were held in individual sealed envelopes by the investigator, to be returned unopened after the trial."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data were nearly fully reported, with less than 10% lost to follow‐up, and reasons were given
Selective reporting (reporting bias)	Low risk	Evidence was available of proper outcome reporting
Other bias	Low risk	No apparent evidence of other risk of bias
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐masked (p.884 ‐ summary): "This was a multicentre, double‐blind..." (p.885 ‐ patients and methods): "active or placebo eye drops (both contained... in addition, the placebo eye drops contained 0.0005% rivoflavin as a yellow colorant to match the 2% nedocromil sodium content of the active eye drops)."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐masked (p.884 ‐ summary): "This was a multicentre, double‐blind..." (p.885 ‐ patients and methods): "active or placebo eye drops (both contained... in addition, the placebo eye drops contained 0.0005% rivoflavin as a yellow colorant to match the 2% nedocromil sodium content of the active eye drops)."