2.9.2. QOL Questionnaire
The subjects completed QOL questionnaires using a visual analog scale (VAS) to assess subjective symptoms. In the VAS method, a 100 mm-long horizontal line was printed, where the left end (0 mm) was defined as the worst condition and the right end (100 mm) was defined as the best condition. The participants expressed their feelings about their QOL. The VAS assessment was conducted pre- and post-VDT operation.