Adler‐Grinberg 1985.

Methods	Study design: Cluster‐randomised, age‐match controlled
Participants	Setting: Schools in 3 US states: California, Georgia, Ohio. Elementary public school students (n = 2440) in 102 classrooms from 26 voluntary schools. Students were from the second, third, fifth and sixth grade classes.
Interventions	Unit of analysis: Classrooms Intervention: 2nd/3rd graders watched an 8‐minute film called "The Eyes Have It" which introduced them to the basic principles of eye health and safety through song. Seven printed worksheets which generated classroom activities reinforced the concepts of the film. The students had 5 sessions which were approximately 20 minutes long. 2nd graders (n = 15), 3rd graders (n = 15) Control: No control, classes carried on as normal. 2nd graders (n = 14), 3rd graders (n = 15) Intervention: 5th/6th graders (n = 21) watched a filmstrip called "The Magic of Sight" with a 13‐minute audiocassette that presented the basic facts about the eye. The instructional package also consisted of a poster illustrating the structure of the eye, 4 tests and a sticker that describes basic first aid procedures for eye emergencies. The students had 5 sessions which were 40 to 60 minutes each. Control: No control, classes carried on as normal. 5th graders (n = 12), 6th graders (n = 10)
Outcomes	Knowledge and attitudes related to eye health and safety: measured by questionnaire given to students Knowledge and attitudes related to eye health and safety: measured by questionnaire given to teachers involved in the programme Knowledge, attitudes and observed behaviour related to eye health and safety: measured by questionnaire given to parents of students involved
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Although schools were randomly assigned to experimental and control groups, there is no mention of how this was done
Allocation concealment?	Unclear risk	There is no mention of how this was done
Blinding? All outcomes	Unclear risk	There is very little information to judge whether the students, teachers, parents or outcome assessors were unaware of the intervention assigned. Teachers were aware of the programme as they were teaching it but parents had not been notified of their child's participation in the programme.
Incomplete outcome data addressed? All outcomes	High risk	There is no mention of drop‐outs or participants excluded from the intervention. There is no mention of what happened to students who did not complete the whole educational package, i.e. they missed a lesson or more than 1 lesson. 29% of teachers in the experimental group and 28% of parents in the control group did not respond to the post‐intervention questionnaire.
Free of selective reporting?	Unclear risk	‐
Confounders?	Unclear risk	‐
Intervention compliance?	Unclear risk	Not reported
Data collection methods?	High risk	Data were collected by questionnaires given to students, teachers involved in teaching the educational package and parents of students involved in the study. For the teachers and parents, the questionnaires were given on a voluntary basis.
Duration of follow‐up?	Unclear risk	For all students (experimental and control), it was 1 day after the programme. For teachers and parents of the experimental group, the questionnaires were given 'following the presentation of the educational unit'.