One embodiment of the invention provides a post extension system frame assembly for mounting fixtures within a recess in a wall or ceiling and that can be adjusted and installed with minimal time and effort. The user’s field of view may be captured in the video images that are processed to select a segment of the video image or an object depicted in the video image. The plurality of segments are removably attached to the main garment through a plurality of fasteners. Furthermore, images of a central retinal artery or a central retinal vein pulse from the subject may be used to define and correlate a pulsatile blood flow with the ONH tissue movement for examination.