Eyeball
noun, の adjective
An eyeball sphere is an eyeball. Eww.
がんきゅう
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
私は自分の左の眼球をあちこち捜したが、なかなか見つけられなかった。
I searched high and low for my left eyeball, but I just couldn’t find it.