| A | B |
|---|
| Eye | Organ of vision that perceives light color shape and depth |
| Photoreceptors | Cells in the retina that respond to changes in light |
| Sclera | Tough white fibrous outer layer that protects the eye from injury and maintains its shape |
| Cornea | Transparent dome-shaped structure that focuses incoming light through the pupil and onto the retina; does not change shape |
| Limbus | Edge of the cornea |
| Conjunctiva | Transparent mucous membrane that lines the sclera and inner eyelids and protects the eye |
| Uvea | Vascular middle layer that nourishes eye tissues; comprised of iris, ciliary body and choroid |
| Iris | Pigmented muscular ring that controls the amount of light entering the eye |
| Pupil | Central opening of the iris that allows light to enter |
| Ciliary Body | Structure that adjusts lens shape and produces aqueous humor |
| Lens | Clear flexible structure that can change shape to focus images sharply onto the retina |
| Choroid | Vascular layer (part of uvea) that supplies oxygen and nutrients to the retina and absorbs excess light and limits reflections |
| Retina | Innermost layer containing photoreceptors that convert light into nerve impulses |
| Rod Cells | Photoreceptors that detect black and white vision and function in low light |
| Cone Cells | Photoreceptors responsible for perception of color and sharp visual acuity |
| Macula | Central region of the retina with a high density of cones (and rods) providing detailed central vision |
| Fovea | Tiny area of highest visual acuity within the macula; contains the highest concentration of just cone receptors |
| Optic Nerve | Cranial nerve that transmits visual information to the brain |
| Optic Disc | Area where optic nerve exits the retina creating a blind spot |
| Aqueous Chamber | Space between cornea and lens filled with aqueous humor |
| Aqueous Humor | Clear fluid that nourishes eye tissues removes waste and maintains pressure |
| Vitreous Chamber | Posterior cavity containing vitreous humor |
| Vitreous Humor | Gel-like substance that maintains eye shape and transports nutrients |
| Orbit | Bony socket that protects the eye |
| Eye Muscles | Three pairs of muscles that coordinate the movement of the eyes; keep them moving together |
| Convergence | Simultaneous inward movement of the eyes for near vision |
| Eyelids | Structures that protect the eye and spread tears |
| Canthus | Junction where upper and lower eyelids meet |
| Eyelashes | Hairs that protect the eye and trigger reflex blinking |
| Lacrimal Glands | Structures that produce tears |
| Tears | Fluid that lubricates cleans and protects the eye |
| Lacrimal Canaliculi | Small channels that drain tears |
| Lacrimal Sac | Structure that collects tears |
| Nasolacrimal Duct | Duct that drains tears into the nasal cavity |
| Refraction | Bending of light rays as they pass through the cornea and lens and enter the eye |
| Accommodation | focal adjustments made by the lens for near and far vision |
| Occipital Lobe | Region of brain that processes visual information |
| Binocular Vision | Use of both eyes to create a single three-dimensional image |
| Depth Perception | Ability to judge distance and spatial relationships |
| Visual Acuity | Ability to distinguish fine detail and sharpness of vision |
| Snellen Chart | Tool used to measure visual acuity |
