Visual problems among electronic and jewelry workers in Thailand

In the processes of electronic and jewelry manufacturing, workers are employed to use their skill in tiny visual tasks (1-3 mm) and near visual distances (<35 cm) that cause visual strain. This study consisted of 3 phases: 1) a survey of workers visual health status and factors affecting their visual strain; 2) the development and implementation of guidelines in the selected factories; and 3) a resurvey to document the change. The baseline survey was conducted in Samutprakan Province during October to December, 2003. Ninety-five percent of the sampled workers were female with an average age of 26.2 yr. Fifty-two percent of the workers had at least one kind of vision problem that might have affected their work performance, and 48.3% of the work sites had substandard illumination levels. The intervention included improvement of lighting conditions, the introduction of short breaks, and correction of visual performance problems. After the intervention, the inadequate lighting problem went down to 24.5%. All factories took a rest break and 20.5% of the workers with inadequate visual performance had corrected their vision in the intervention period. Comparing pre-intervention status with the end of the program, the Critical Fusion Frequency (CFF) at one hour and two hours of work were improved with statistical significance among the electronic but not the jewelry workers. In conclusion, visual problems among vision intensive industrial workers are common. Intervention programs partially but significantly improved the situation.