(7) Eyes & Visual Pathway Flashcards
List the 7 bones of the orbit:
- Frontal
- Sphenoid
- Ethmoid
- Lacrimal
- Maxilla
- Zygomatic
- Palatine
List the 3 anatomical structures of the eyelid:
- Palpebral fissure (open area b/w eyelids)
- Tarsal plates
- Levator palpebrae muscle
What anatomical feature is best described: “connective tissue at each corner with meibomian glands that produce oily lubricant for surface of eye”
Tarsal plates
What innervates the levator palpebrae muscle and what is its function?
CN III (Oculomotor) innervates the levator palpebrae muscle; elevates the eyelid
List 3 functions of the eyelid:
- Distribute tears across eye surface
- Limit light that enters eye
- Together with eyelashes, protect from FB (blinking mechanism)
What are 3 chambers of the eye?
- Anterior – between cornea and iris
- Posterior – between iris and lens
- Vitreous – between lens and retina
List 5 anatomical structures of the anterior chamber of the eye: “CSCIP”
- Conjunctiva
- Sclera
- Cornea
- Iris
- Pupil
Define Conjunctiva and its 2 parts:
Vascular, clear mucous membrane
2 continuous parts:
Bulbar conjunctiva – covers anterior eye/sclera
Palpebral conjunctiva – lines the eyelids
What is the function of the Conjunctiva?
Provides protection/lubrication to cornea and sclera; keep things from getting to the back of the eye
Define Sclera:
White of the eye; Opaque, fibrous, protective, outer layer
Define Cornea:
- transparent
- avascular
- covers the Iris & Pupil
Define Limbus:
border between the cornea and the sclera
Define Iris and its function:
Colored, circular muscle that controls constriction/dilation of the pupil and amount of light entering
Dilation with light? Sympathetic or parasympathetic? Drug influence?
Dilation occurs with less light, sympathetic innervation. Can be seen with cocaine/ecstasy.
Constriction with light? Sympathetic or parasympathetic? Drug influence?
Constriction occurs with bright lights, parasympathetic innervation. Can be seen with opiates, fentanyl, heroin.
Define Pupil:
Eye’s aperture, which allows light to travel through eye to the retina
Describe the 3 functions of Tears:
- Prevent excessive drying of the surfaces of the conjunctiva & cornea
- Provide nutrition and oxygen to surface structures
- Possess antibacterial properties
Describe the 3 layers of Tears and their associated glands:
- Mucous layer – Conjunctival cells
- Lipid/oil layer – Meibomian glands
- Watery layer – Lacrimal glands
Describe the Lacrimal Apparatus:
The lacrimal apparatus is a group of structures responsible for generating, and collecting and draining the Tear fluid
Lacrimal gland → sweeps across eye to two punctum medially → Drain into lacrimal sac, down nasolacrimal duct → into inferior nasal turbinate
List 2 anatomical structures of the posterior chamber of the eye:
- Lens
- Ciliary body
Define Lens:
- suspended by ligaments (zonule fibers)
- muscles of the ciliary body control the thickness of the lens
- Allows eye to focus on near/distant objects (accommodation)
Define aqueous humor:
Ciliary body produce aqueous humor that fills posterior chambers to anterior chamber via pupil → Drains out through canal of Schlemm → controls the intraocular pressure
Describe the vitreous body and its function:
Gelatinous material posterior to the lens that maintain eye shape
Describe the Optic Fundus and its (7) components:
The fundus of the eye is the interior surface of the eye includes the Retina, Choroid, Macula, Fovea, Optic disc, Physiologic cup, Retinal vessels
Describe the Choroid:
Vascular tissue between sclera and retina, feeds nerves of lateral retina
Components of the Retina:
Neural retina contains the visual receptor cells (the rods and cones)
Rods: absorbs a wide bandwidth of light
Cones: absorbs color of light
Describe Macula:
Functional center of the retina with high resolution color vision (cones)
Describe Fovea:
Center of macula; central vision (has most cones)
Describe Optic Disc:
Where optic nerve exits & retinal vessels enters the eye
Describe Physiologic Cup:
White, cup-like area in center of optic disc;
in glaucoma, when there is damage to the optic nerve, the cupping increases
List the 5 Extra-ocular Muscles and its associated innervation: “(LR6 SO4) AO3”
Superior Rectus (CN III; oculomotor)
Inferior Rectus (CN III; oculomotor)
Medial Rectus (CN III; oculomotor)
Lateral Rectus (CN VI; abducens)
Superior Oblique (CN IV; trochlear)
Inferior Oblique (CN III; oculomotor)
List the (17) ROS for the eyes:
- Last eye exam and results
- Vision changes
- Glasses or contacts
- Prior surgery or injury
- Eye medications such as drops
- Eye pain
- Redness
- Excessive tearing or dryness
- Discharge
- Double vision (diplopia)
- Blurred vision
- Scotomata (spots/specks)
- Photophobia
- Flashing lights
- Glaucoma
- Cataracts
- Icterus
“The entire area seen by an eye when it looks at a central point”
Visual Field Center
-has the greatest visual acuity and color sensitivity
-photopic “light-adapted”
“15 degrees temporal to line of gaze”
“sits in the part of your retina where the optic nerve exits the eye, and there are no photoreceptors (rods or cones) in the optic disk, and, therefore, there is no image in this area”
Blind Spot
“Overlap of both fields of vision; producing a single image from the two disparate monocular images”
Binocular vision
-The images of the corresponding (binocular) space are slightly different in each eye. The nervous system fuses these disparate binocular images to produce a single image (e.g., of the pencil located an arm’s length away).
List the (6) anatomic structures of the eye through which reflected light must pass in order to strike upon the retina (optic pathway).
Reflected light travels from Cornea → Anterior Chamber → Pupil → Lens → Vitreous body → be focused on photoreceptors in the Retina → the projected image on the Retina is upside down and reversed right to left
What are (2) reasons pupillary size changes?
- In response to light
- To focus on near object
What are (2) types of light reaction? What nerves are stimulated (sensory and motor nerve)?
- Direct reaction; pupillary constriction of stimulated eye
- Consensual reaction; constriction of opposite pupil
Sensory - afferent - Optic (CN II)
Motor - efferent - Oculomotor (CN III)
Define Near Reaction and its associated nerve:
Pupil constriction when shifting gaze from far object to near object
Mediated by oculomotor nerve (CN III)