Final answer:
The word root pertaining to the eye is 'op-' or 'ophthalm-', as found in medical terminology related to the anatomy and diseases of the eye.
Step-by-step explanation:
The word root for "pertaining to the eye" is op- or ophthalm-. This is evident in terms such as ophthalmic artery, which supplies blood to the eye, and optic canal, through which the optic nerve passes. These roots are essential in the medical field, particularly in ophthalmology, the branch of medicine that deals with the anatomy, physiology, and diseases of the eyeball and orbit.