Eye Anatomy 8- 24 - 26

Exophthalmos

Protrusion of the eye

Cornea

Covers the iris and the pupil.

Conjunctiva

Three different types:

1.Palpebral

2.Bulbar

3.Fornix

Palpebral conjunctiva

Lines the inner surface of the eyelids

Bulbar conjucriva

Covers anterior portion of the sclera

Fornix conjunctiva

Flexible fold connecting Palpebral and bulbar region.

Limbus

Junction between cornea and sclera. Conjunctiva does not cross cornea because that could impair vision.

Osteogenesis imperfecta

Causes blue color of sclera

Arcus senile

Can come w/old age - this can happen younger if diet is bad (fatty)

Wilsons diagnosis

Too much copper in the body

Sphincter pupillae

Circular muscle around the pupil that causes miosis (construction). Involved in ANS of parasympathetic region.

Dilator pupillae

Muscle causing pupillary mydriasis ( dilation). Crucial in the ANS of sympathetic region,

Perrla

Pupils equal round and reactive to light and accommodations

Canthus

There is the medial and lateral - they are the angles of the eye

Superior and inferior lacrimal papillae

Raised structure that contains the puncta, which is where tears drain.

Palpebrae - what are the 5 layers?

Eyelids

1. Skin

2. Subcutaneous tissue

3. Muscles

4. Tarsal plate

5. Conjunctiva

Hordeolom

Style - bacterial

Two types:

Internal hordeolum- infection of tarsal gland

External hordeolum- infection of ciliary gland

Chalazion

Inflammation of tarsal (melbomian) gland - not an infection- due to a build up in ails.

Eyelid muscle

1. Orbiculars oculi - help with pinching eye shut. Blinking. Innervated by CN VII

2. Levator palpebrae superioris- pulls back upper eyelid. Innervated by CN III. If damaged it can cause ptosis.

3. Superior tarsal muscle- works with the levator palpebrae, especially during stress or surprise.

Orbital cellulitis

Infection that occurs in post orbital septum.

Symptoms include erythema, edema, purulent, and mild entrapment or bulging

Usually developed from the ethmoid sinus

Trachoma

A severe form of bacterial conjunctivitis. Specifically due to chlymidia trachomatis.

Dx progression includes:

1. Cicatrization- corneal scarring

2. Entropion- eyelid inversion

Trichiasis - eyelashes brushing cornea leads to corneal blindness

Lacrimal gland

For secretion of tears into sclera.

Route: tears are secreted by the lacrimal gland into the sclera. Tears go to the lacrimal papillae to be drained by the punctum, the puncture leads into the lacrimal canalcoli to the sac holding place for tears, until it is drained out of nasal each mal duct to the nasal meatus.

Dacryocystits.vs dacryodenothis

Inflammation of the lacrimal sac.

Inflammation of lacrimal gland

Eye muscles:

Superior rectus: for elevation of the eye, but also adduction ( move eye towards nose )

Lateral rectus: abduction (move eye away fromnose). Innervated by CN VI

Medial rector: adduction

Inferior rector: depression /lowering the eye

Superior oblique: depresses abducts and medially rotates. Intervated by CN IV

Inferior oblique: elevates, abducts, and laterally rotates. Intervated by CN III

Responsible for eyelid movement and which for eye movement

Eye : recti and oblique

Eyelid: levator papillae superions -elevates upper eyelid

Someone presents to the Ed and their pupils do not react to light. What is happening?

Parasympathetic problem win CN 3 (could be intracranial pressure )

Edinger westphal nucleus: plays a key role in autonomic eye control such as pupil constriction /miosis

Homers syndrome characteristics

1. miosis

2. Anhidrosis

3. Ptosis

Homer syndrome could arise from pancoast tumor, lateral brain stem infarction, carotid dissection.

What is the fibrous, neural, and vascular layer of the eye?

Fibrous is sclera and cornea

Vascular is the uvea which is the choroid, ciliary body, and iris

Optic nerve critical vessels

Central retinal artery and vein.

Posterior compartment of the eye

Goes from the lens to the retina

Anterior compartment of the eye

The iris divides the anterior from posterior - this chamber contains aqueous fluid

Where does aqueous humor come from?

The ciliary body

Aqueous humor comes from the ciliary body, goes around the iris and into the antenor chamber where the trabecular meshwork is, which goes into schlamm’s canal into I the vein.

Open angle vs closed angle glaucoma

Closed angle is when the iridocorneal angle, where the trabecular meshwork is, is pinched 10ff which doesn't allow aqueous humor to drain.

This is a medical emergency!

Open angle is when the iridocorneal angle is open but the trabecular meshwork is not draining or drains too slow.

How does the lens work for near farsighted vision?

The lens has an important ligament called the zonules of zinn.

One end of zonules of zinn connects to the ciliary bony the other to the lens

Two things can happen :

1. Circular fibers of ciliary body contract, zonules loosen, lens become bulbous = near vision

2. Circular fibers relax, zonules tighten, the lens flatten,= distant vision

Myopia

Nearsighted → the globe is too long, but can be fixed w/ concave lens

Hyperopia

Farsighted → globe is too short for lens, fixed w/convex lens.

Vessels of the eye. Which is darker? Lighter?

The arteries are lighter on a fundoscopic exam while the veins are darker.

Diabetic retinopathy

Hard exudates: proteins and lipids that have exudate out of blood vessel

Cotton wool spots: indicative of ischemia. Yellow/orange and larger than n the hard exudates.

Hemorrhages: where blood has leaked into the retina ( shadow looking)

Proliferative diabetic retinopathy → extra smaller blood vessels grow. Usually a response to ischemia.

Papilledema: bright contrast between optic disc and retina reduced, this can signify high intercranial pressure (meaning don't do a spinal tap)

This term specifically means smelling at the optic disc

Central retinal vein occlusion → Blood and thunder finding

Commonly occurs due to a thrombotic event. Retina suffers from blood flow in and out

Key detail: it is painless

High contrast cup to disc ratio is what condition?

Glaucoma

This is entirely opposite of papilledema

Hypertensive retinopathy

Due to high BP (210/140)

To true be diagnosed this it has to have stage 4 papilledema

Macular degeneration -dry type

Drusen: cholesterol droplets + protein + calcium phosphate → this collects in the retina

The macula thins over time and drusen deposits under the retina

Macular degeneration-wet type

Endothelial injury →hemorraging/scarring