2.7. Randomization
This was a double-blind study. An individual not involved in the evaluation of the study was designated as the allocation manager. The allocation manager checked the indistinguishability of each test item, allocated it, and was blinded to the test items. The allocation manager prepared an allocation table using the substitution block method to ensure that there was no bias between age, sex, and change in the eye–hand coordination time pre- and post-VDT operation during the screening test in the two groups. The allocation tables were strictly sealed and not opened until the participants were analyzed.