before vowels ophthalm-, word-forming element meaning "eye," mostly in plural, "the eyes," from Greek ophthalmo-, comb. form of ophthalmos "eye," originally "the seeing," of uncertain origin. Perhaps from ops "eye" (see optic) + a form related to thalamos "inner room, chamber" (see thalamus), giving the whole a sense of "eye and eye socket."
ophthalmo- or ophthalm-
Eye; eyeball: ophthalmoscope.