How does Vision Work ?

http://www.evrs.eu/en/how-does-vision-work/ -
How does Vision Work ? -

To better understand Retinal Vitreo Disorders, we must first examine how vision works. In order for one to see, a light source is required. Without light, everything is black. The light emits particles called photons, which bounce off solid objects in all directions before eventually reaching the eye. In order to see well, the tissue that they go through must be transparent.