The basic components of the vertebrate eye are a transparent cornea, an adjustable iris, a lens for focusing, a sensitive retina lining the back of the eye, and a clear fluid- or jelly-filled center. The most primitive animals only have one or two eyespots, while many other invertebrates have several simple eyes or a pair of compound eyes
verb (eyes, eyeing or eying, eyed)[with object]
Old English ēage, of Germanic origin; related to Dutch oog and German Auge
Eyeing is usually spelled with a second e, although eying is also correct.