Vision

Lacrimal Apparatus

Tear gland and multiple ducts that drain tears into the nasal cavity.

Function of Lacrimal Apparatus

Cleanses and lubricates the eye surface, protects from infection, delivers oxygen/nutrients to the conjunctiva.

Sclera

The white part of the eye that serves as a protective cover and attachment for muscles to move the eye.

Cornea

The anterior, transparent region of the eye that transmits light.

Uvea

The middle vascular layer of the eye that contains the iris, choroid, and ciliary body.

Choroid

Vascular, pigmented layer behind the retina that provides oxygen, nutrients, and waste removal for the outer layer of the retina.

Ciliary Body

Extension of choroid forming a muscle ring around the lens that supports the iris and secretes aqueous humor.

Iris

The colored part of the eye that is adjustable and supports the pupil.

Pupil

The black dot of the eye that serves as the opening to the eye.

Chromatophores

Pigments in the eye that give it color.

Retina

Layer of photoreceptor cells that detect light and convert it into neural signals.

Optic Disc

The point where the optic nerve exits the eye, leading to a temporary blind spot.

Optic Nerve

Carries electrical impulses generated by the retina to the visual cortex.

Aqueous Humor

Clear fluid that fills the space between the cornea and lens, maintaining intraocular pressure and providing nutrients.

Posterior Chamber

The space between the iris and lens.

Anterior Chamber

The space between the iris and cornea.

Lens

Made of many compacted lens fibers.

Suspensory Ligaments

Ring of fibers behind the pupil that attaches the lens to the ciliary body.

Vitreous Body

Jelly that fills the vitreous chamber behind the lens, maintaining intraocular pressure and supporting the eye's shape.

Ora Serrata

The part of the eye where the optic nerve exits, lacking photoreceptors.

Pupillary Constrictor

Smooth muscle encircling the eye that narrows the pupil to admit less light.

Refraction

The bending of light rays.

Convergence of Eyes

Both eyes orient in the same direction.

Diplopia

Double vision resulting from one eye’s muscle being weaker than the other.

Pupil Constriction

The process that causes focus on nearby objects.

Accommodation of Lens

The change in lens curve to focus on nearby objects.

Near Point of Vision

The closest an object can be without appearing blurry.

Pigmented Retina Layer

Contains stray light and prevents it from reflecting back to degrade the image.

Neural Retina Layer

Contains photoreceptor cells that reabsorb light to create chemical/mechanical signals.

Photoreceptor Cells

Cells that reabsorb light in the retina; include rods and cones.

Rods

Photoreceptor cells that contain visual pigment rhodopsin; function in night and monochromatic vision.

Cones

Photoreceptor cells that contain visual pigment photopsin; function in day and color vision.

Bipolar Cells

First-order neurons of the visual pathway that synapse with rods and cones.

Ganglion Cells

Largest neurons in the retina that form the optic nerve and transmit signals to brainstem nuclei for control of pupillary diameter and circadian rhythm.