Cyanobacteria use their whole bodies as eyeballs
Round single cells may have been the first creatures to see Earth
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2016/02/ticker_cyanobacteria_free.jpg?fit=860%2C460&ssl=1)
HEY LOOK The spherical bacteria Synechocystis (shown here in false color) can use their single-celled bodies almost like eyeballs. A light shining up from the bottom of this image passes through the cells and focuses on the far side (white arrows highlight examples of focused light). A laser light source in the center (red dot) helped test which way the cells move in reaction to bright spots of light.
N. Schuergers et al/eLife 2016