PHYWE Human eye, functional model

This model is a mechanical copy of an eyeball. The back part of which is formed as a projection surface and is removable various eyeball lengths can be attained by inserting spacer rings correction of sight defects is achieved with lenses placed in front of the model it allows a vivid demonstration ofs hort-sightedness and long-sightedness compared to the normal vision of the human eye and of how such defects can be corrected the image on the "retina" (projection surface) is not turned rightside up, as it is by brain activity and is so seen upside down.  Eyeball 2 spacer rings 2 lens diameter: 110mm