Slashing Two-wheeled Accidents by Leveraging Eyecare

STABLE is a stepped-wedge cluster randomised controlled trial and its primary aim is to determine whether the provision of spectacles for the correction of myopia can reduce the average number of crash-near-crash (CNC) events among eligible motorcycle drivers in Vietnam as measured under naturalistic driving conditions with the Data Acquisition System (DAS).

STABLE is designed to assess the impact of vision correction on the safety of road users in a a Low and Middle income countries (LMIC) setting. A positive trial outcome would demonstrate the safety benefits of vision correction and would create pressure for tighter regulation of drivers' vision and the promotion of vision correction.

The study will be conducted in the peri-urban universities in Ho Chi Minh City, Vietnam and 625 students from five universities will be recruited into the trial.

Before conducting the main trial, a pilot of 35 students will be recruited to test DAS and build CNC dictionary.

Duration of the trial is 33 months from enrolment to completion of primary analysis, with 18 months for data collection.

Study participants can be both male and female motorcycle drivers aged 18 to 23 years years with at least one year of driving experience; they must use their motorcycle as their primary means of transport; drive at least 25 km per week and present with un- or under-corrected myopia that can be corrected with spectacles.

Participants with any ocular or systemic abnormality affecting vision, other than un-or under-corrected myopia will be excluded from the trial.

STABLE's primary outcome is CNC events per 1,000 km driven the DAS mounted to the motorcycles of trial participants. An interim analysis of the primary outcome will take place 9 months after data collection begins. The interim analysis will be reviewed by the trial's Data Monitoring and Ethics Committee. Unless a change is needed because of this review, the trial's primary analysis will take place 18 months after the DAS units are fitted to participants' motorcycle).

Compliance with study glasses; self-reported visual function (driving-adapted Visual Function Questionnaire-25 \[VFQ-25\]); Dula Dangerous Driving Index (DDDI), for all crashes; self-reported CNC events for comparison with recorded CNC events and total delivery cost per CNC event avoided with the intervention (indicator of cost-effectiveness).