Noun | 1. | ![]() sense organ, sensory receptor, receptor - an organ having nerve endings (in the skin or viscera or eye or ear or nose or mouth) that respond to stimulation visual system - the sensory system for vision naked eye - the eye unaided by any optical instrument that alters the power of vision or alters the apparent size or distance of objects; "it is not safe to look directly at the sun with the naked eye" peeper - an informal term referring to the eye oculus dexter, OD - the right eye oculus sinister, OS - the left eye compound eye - in insects and some crustaceans: composed of many light-sensitive elements each forming a portion of an image choroid, choroid coat - a highly vascular membrane in the eye between the retina and the sclera; a dark pigmentation minimizes the scattering of light inside the eye ciliary body - the part of the tunic of the eye between the choroid coat and the iris; "the ciliary body produces aqueous humor" eyelid, lid, palpebra - either of two folds of skin that can be moved to cover or open the eye; "his lids would stay open no longer" canthus - either of the corners of the eye where the upper and lower eyelids meet epicanthic fold, epicanthus - a vertical fold of skin over the nasal canthus; normal for Mongolian peoples; sometimes occurs in Down's syndrome nictitating membrane, third eyelid - a protective fold of skin in the eyes of reptiles and birds and some mammals conjunctiva - a transparent lubricating mucous membrane that covers the eyeball and the under surface of the eyelid eye muscle, ocular muscle - one of the small muscles of the eye that serve to rotate the eyeball cornea - the transparent dome-shaped anterior portion of the outer covering of the eye; it covers the iris and pupil and is continuous with the sclera uvea - the part of the eye that contains the iris and ciliary body and choroid uveoscleral pathway - a tubule that drains excess aqueous humor iris - muscular diaphragm that controls the size of the pupil which in turn controls the amount of light that enters the eye; it forms the colored portion of the eye crystalline lens, lens of the eye, lens - biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focuses light on the retina arteria centralis retinae, central artery of the retina - a branch of the ophthalmic artery; enters the eyeball with the optic nerve arteria ciliaris, ciliary artery - one of several arteries supplying the choroid coat of the eye arteria lacrimalis, lacrimal artery - an artery that originates from the ophthalmic artery and supplies the lacrimal gland and rectal eye muscles and the upper eyelid and the forehead lacrimal vein, vena lacrimalis - drains the lacrimal gland; empties into the superior ophthalmic vein lacrimal apparatus - the structures that secrete and drain tears from the eye retina - the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve sclera, sclerotic coat - the whitish fibrous membrane (albuginea) that with the cornea forms the outer covering and protection of the eyeball musculus sphincter pupillae, pupillary sphincter - a ring of smooth muscle surrounding the iris face, human face - the front of the human head from the forehead to the chin and ear to ear; "he washed his face"; "I wish I had seen the look on his face when he got the news" colloquialism - a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech aperture - a natural opening in something |