## 2 Complete System Description  
Shapes and materials previously studied [1] were used to create and assemble the system as presented in Figure 2a,b. The first of the two shows a frontal view of the marker  
Figure 1: Front and isometric views of the model used for lateral marker support.  
support system, as viewed by the optometrist. It comprises two compliant mechanisms: (1), one for each of the two openings of the glasses frames on which the system will sit by means of supports (2), (3) and (4). A large number of supports is needed to accommodate a large number of the shapes and sizes of glasses frames. As such, the mounting of the device onto a pair of glasses is performed by applying a force of up to 30 N to each side of the frame using handles (8), resulting in a larger opening between supports (2) and (4), as well as (2) and (3). Next, supports (3) and (4) are placed on the upper side of the frame, (2) is placed on the lower side and the force is removed. The bridge between the two lateral compliant mechanisms is flexible, allowing the support to match the glasses frame's curvature. The bridge comprises a central fixed section (6), a flexible portion (5) and a fixed marker support section (7). Lateral marker support is offered by means of support (9).  
The device is built in modules to both allow, in some instances, for different materials to be used and improve on some of the parameters of the final product. Printing three separate parts allows for better quality, lower print times and a wider range of desktop printers that might be used to manufacture the device.  
Regarding the movement of the markers due to the deformation of the device, both the lateral (side) markers and the central ones are mounted on small, single cantilever plates  
Figure 2: Views of the complete optometric model used for lateral marker support: (**a**)—front view; (**b**)—isometric and lateral views.  
that are not deformed during the mounting process. The distance between these points is known (calibrated) and serves as a reference during the measurements. The idea of directly printing the colour markers was certainly considered; issues with material colour consistency convinced us to use conventionally printed colour markers.  
The support is used to position a set of markers relative to a user's face and determine, using a method to be discussed in another paper, dimensions specific to the user's facial parameters and chosen glasses frames. It allows for the acquisition of parameters such as the following: pupillary and interpupillary distance, curvature of the glasses frames, pantoscopic angle on both sides of the user's face as well as measurements related to customizing the lens to the glasses frames. The markers used are manufactured on adhesive, low-gloss paper of a specific colour and are positioned using a specially made stencil in order to guarantee their position. Figure 3 shows a chart of the measurements that can be taken using this system. This system allows all necessary parameters to be determined by taking both a close-up and a far picture of the patient wearing the glasses and marker support assembly.  
Among the measurements that can be taken are the following: IDR (interupillary distance, total as well as right IDR and left IDL), LW (lens width, both left and right), LH (lens height, left and right), BW (Bridge Width), BHR and BHL (pupil distance to lower part of lens) as well as BIL and BIR (pupil distance to lower part of lens). Along these, measurements related to vertex distance (VL and VD), distance between the pupil and lens, PAR and PAL (left and right pantoscopic angle) as well as the glasses frame curvature FC are included.