Fig. 1

a. Simulation of the Height 1, where the operator is at a stand up height and maintain the mobile device 30 cm from his head, 1.5 m from the floor and 1 meter from the patient. b. Simulation of the Height 2, where the operator sits on the higher height of the chair with wheels and maintain the mobile device 30 cm from his head, 1.25 m from the floor and 1 meter from the patient. c. Simulation of the Height 3, where the operator sits on the lower height of the chair with wheels and maintain the mobile device 30 cm from his head, 1 m from the floor and 1 meter from the patient