The study hypothesis is that low dose atropine eye drops will reduce the progression of short-sightedness in children compared with placebo eye drops. This is a randomised controlled trial which will be conducted across four Clinical Research Facilities associated with higher education institutions in the UK. It is a double masked trial, that is, neither the participant or the research team will know what treatment the participants are receiving. 289 children aged 6-12 years with short-sightedness will be recruited to the trial. They will be randomly chosen to receive either atropine eye drops or placebo eye drops on a 2:1 basis. Therefore, 193 participants will receive atropine eye drops, 96 participants will receive placebo eye drops.

Potential participants will be referred either by their high street optician or their parents will refer them directly. The study will be advertised on local radio. Potential participants will be invited to attend a baseline screening visit. Written informed consent and written informed assent will be obtained from the parent and child prior to undertaking any assessments. Potential participants will undergo a number of assessments similar to what is conducted by the high street optician or eye clinic to determine if they are eligible to participate. These include: assessment of near and distance vision, reading speed and different measurements of the eye using instruments. An eye drop will be put into each eye for some of these assessments. These drops cause a short-term increase in pupil size, which may last for 12-24 hours, and make close up vision (through their glasses) blurry for up to four hours, and may make them more sensitive to bright light. Participants will also be asked about their quality of life and their daily activities such as screen time, playing outside and reading.

Participants will be instructed in the use of the eye drops. They will put one drop in each eye daily for 24 months. The atropine eye drops contain 0.01% atropine sulphate. Placebo eye drops have been chosen as the comparator group as there is no alternative treatment for this condition. Participants will be given a six month supply of eye drops at each visit (except the last visit at 24 months). This will include seven bottles as each bottle can only be used for 28 days after opening.

Participants will have a further four visits to the research facility for the assessments to be repeated. This will be every six months, therefore five visits in total (baseline, 6 months, 12 months, 18 months and 24 months). It is anticipated that each visit will last approximately 1-2 hours. Children will be offered the opportunity to rest between assessments. At these follow up visits, in addition to the assessments, they will be asked about their tolerability of the eye drops. Also, five years after randomisation, the investigators will post a questionnaire to participants and ask details of any possible complications and adverse events. The investigators will also request information from their optometrist regarding their eye health, distance vision and refractive error data.

The primary outcome is the change in the severity of short-sightedness after 24 months. This will be measured using a machine called an autorefractor.