Changes

| 17th century || Before the century, almose almost no one suspected there was life too small to see with the naked eye, with fleas thought to be the smallest possible form of life.<ref name="The Science Book: Big Ideas Simply Explained"/> {{w|Johannes Kepler}} is generally considered by neuroscentists as the first to recognize that images are projected, inverted and reversed by the eye's lens onto the {{w|retina}}.<ref name="Visual Approaches to Cognitive Education With Technology Integration"/> By the mid 17th century {{w|Robert Hooke}} and {{w|Antonie van Leeuwenhoek}} take the microscope to new levels of development.<ref name="History of Microscopes"/>