Test 4: Eye Flashcards
Duct System
Runs under eyelid
produces tears
Lacrimal Punctum
Drains into lacrimal sac
Nasolacrimal Duct
Drains into inferior meatus of nasal cavity
Orbital Axis
23 degrees from midline/optic or visual axis
-can align orbital and optic axis but only one eye at a time
Tear Pathway
1) Duct System
2) Lacrimal Punctum
3) Lacrimal Canaliculus
4) Lacrimal Sac
5) Nasolacrimal Duct
6) Inferior Meatus in Nasal Cavity
7) Sinuses
8) Swallowed
Optic Canal
Optic Nerve (CN2) and ophthalmic artery goes through
Superior Orbital Fissure
1) Contains nerves and vessels other than optic nerve and ophthalmic artery
- supply face and orbit
2) Nerves/vessels–>Supraorbital Notch–>Forehead
Inferior Orbital Fissure
1) Continous
- posteriorly w/ ptergyopalatine fossa
- inferiorly w/ infra temporal fossa
2) Maxillary Division of Trigeminal Nerve (CN5) runs through the floor
- part passes through infraorbital sulcus–>Infraorbital foramen–>Face
Orbit
1) Protected Laterally by frontal and zygomatic bones
Para Nasal Sinuses
1) Separated from orbit by thin plates of bone
Orbicularis Oculi Muscle
1) Encircles the eye and in eyelid
2) Open/closes eye
Tarsal Plates
1) Superior & Inferior
2) Protective Function
- Contain Meibomian Glands (AKA tarsal glands)-secrete oily substance/lipids that lubricates the lid margins so eyelids don’t stick together
- prevents tears from overflowing onto the face
Conjuctiva
1) Thin translucent mucous membrane
2) Palpebral Conjuctiva
- lines inner surface of eyelids
- reflected at fornices (superior and inferior)
- attached to tarsal plates
- vascular
3) Ocular Conjuctiva
- loosely attached to sclera
- Translucent & Avascular so sclera is visible
- over cornea- only consists of epithelium layer
Conjucvitis
1) AKA pink eye
2) inflammation of conductive
3) Bacterial
- Treatable w/ antibiotics and steroids
4) Viral
- Has to run its course
- Tx: Steroid
Bulbar Fascia
1) AKA Tenon’s Capsule
2) Thin fibrous capsule that convers eye
- optic nerve (posterior) to corneal-scleral junction (Anterior)
- anchors eye to CT
3) Pierced by tendons of extra ocular Muscles
- forms sheath around muscle
Superior Tarsal Muscle
1) Smooth Muscle
2) Under control of sympathetics
- K/0=relax->Drooping eyelid=PTOSIS (Horners Syndrome)
Levator Papebrae Superioris Muscle
1) Skeletal Muscle
2) Attaches to superior tarsal plate
Medial/Lateral Palpebral Ligament
1) Helps anchor the tarsal plates within orbit
2) Attaches:
- medially to lacrimal and maxillary bones
- laterally to zygomatic bones
Extraoccular Muscles
1) Superior Oblique Muscle
2) Inferior Oblique Muscle
3) Levator Palpebrae Superioris Muscle
4) Superior Rectus Muscle
5) Medial Rectus Muscle
6) Inferior Rectus Muscle
7) Lateral Rectus Muscle
8) Pulley (Trochlea)
- idk if this is muscle
Superior Oblique Muscle
1) Extraocular Muscle
2) Innervates lateral side of eye
3) loops through Pulley (Trochlea)
4) Contracts- rotate eye
Inferior Oblique Muscle
1) Extraocular Muscle
2) Innervates Lateral Side of eye
3) Contracts-rotate eye
Tunics of eye
1) External Fibrous Tunic
- Cornea & Sclera
2) Middle Vascular Tunic
- Choroid, Ciliary Body, Iris
3) Internal Nervous Tunic
- Retina
Lens
1) Biconvex Disc
2_ Bends light as it passes through
3) 1 cm diameter
4) Enclosed in capsule
5) Attached to ciliary body by suspensory ligaments (AKA zonular Fibers)
-contraction of ciliary musculature (Parasympathetic)=relax suspensory ligaments
-becomes more convex (Round)
-resutls in more refractive power for near vision
6) Accommodation
-altering the convexity/shape of lens to bring object into focus
Accommodation
1) Alter the convexity/shape of lens to bring object into focus
Cornea
1) Translucent
- avascular and no lymph vessels
- receives nutrients via diffusion
2) Continuous with sclera
3) Specialized collagen that allows light through
4) Takes a long time to heal due to lack of vasculature and lymph
5) No transplant rejection
- tissue type doesn’t matter bc blind to immune system
Vitreous Chamber
1) Behind Lens
2) Vitreous Humor
-clear gel like
-not filled with guild
no turnover
Anterior Chamber
1) In front of Lens & Iris
- behind cornea
2) Contains Aqueous Humor
- fluid like substance
- turned over
- made by ciliary processes
Ciliary Body
1) Contain Ciliary Processes
- span from posterior chamber through pupil into anterior chamber
- produce aqueous humor continuous
2) Contain Ciliary Muscle
- Smooth Muscle
- Controls shape of lens by putting tension on Zonule Fibers
- sphincter sapped
- contract=smaller
Pathway of Aqueous Humor
1) Ciliary Processes
2) Iridial/filtration angle
3) Sinus Venous Sclerae
4) Trabecular Meshwork
5) Spaces of Fontana
6) Canal of Schlemm
7) Aqueous Vein
8) Anterior Ciliary Vein
Glaucoma
1) Blockage of aqueous humor/fluid outflow
2) Can lead to blindness
3) Increased intraocular pressure
- most likely draining problem
4) TX:
- drugs that inhibit parasympathetic component (Ach)
- which dilates pupil=iris expanding
2 Types 1) Open Angle -AKA chronic Glaucoma -Most common (90%) 0free flow around angle, but issue with trabecular meshwork 2) Angle Closure Glaucoma (5%) -AKA acute glaucoma -Obstructing flow of fluid @ iridial/filtration angle -not chronic -more of problem when in dark room -Most common in asians
Posterior Chamber
1) Fluid Filled
- same as anterior chamber
2) Lateral to lens
3) Contains ciliary bodies/processes/muscles
Iris
1) Smooth Muscle
2) Makes pupil smaller or larger
3) Composed of
Sphincter Pupillae
-concentric
-parasympathetic
Dilator Pupillae
- radial (Bicycle spikes)
- sympathetic
Zonule Fibers
1) Attach lens to ciliary process
2) Found in posterior chamber
Retina
1) Visual Activity not same throughout
2) Layers
Retina Proper
-most interior
-photosensitive cells
Choroid
Sclera
- white of eyes
- most exterior
Optic Disk
1) Blind spot
- when both eyes are used do not have blind spot in visual field
Fovea Centralis
1) most Acute vision
- most accurate vision
- most sensitive to light
2) In line w/optic axis
Corneal Epithelium
1) Stratified Squamous Nonkeratinized
Corneal Endothelium
1) Simple Squamous
Iridial Angle
1) AKA filtration angle
2) B/w iris and cornea
3) collapses in acute Glaucoma
Astigmatism
1) Type of abnormal curve of lens or cornea
- bend light differently
2) Occurs by:
- Odd shaped cornea
- Odd shaped lens shape
Cataracts
1) Occurs overtime
2) Lens becomes more opaque/cloudy
3) Crystallin Proteins in lens begin to aggregate (Cross-link)
4) Tx: Surgery
- emulsify and aspirate lens
- insert artificial lens into capsule
5) Caused by:
- UV light
- Diabetes
- Free radicals
Photokeratitis
1) Sun burnt eyeballs
2) UV damage of corneal epithelium
3) Eventually Heals
Presbyopia
1) Lens hardens
- less likely to be spherical
2) Progressive–>Gets worse with age
- 40 y.o. avg age of onset
3) Separate pathology from near/far vision
4) Problem w/accomodation
5) Anterior/posterior diameter will not increase much even with tension on zonula fibers
Near Vision
1) Changes lens shape to focus on things close
2) Edinger wesphal stimulate ciliary muscles to contract causing less tension on zonula fibers
- anterior posterior length is greater (sphere)
- EW stimulates parasympathetic system of CN3
Far Vision
1) Ciliary muscles relax
2) Increases tension of ZOnule fibers
- stretch to oval shape
3) Anterior posterior length is less
