Flashcards in Eyes Deck (65)
What are the three layers of the eyeball?
External - sclera and cornea
Intermediate - anterior (iris and ciliary body) and posterior (choroid)
Internal - retina
What is the anterior chamber of the eye?
Between the cornea and iris
Filled with aqueous humor
What is the posterior chamber of the eye?
Between the iris, zonule fibers and lens
Filled with aqueous humor
What is the vitreous chamber of the eye?
between lens and retina
Filled with vitreous humor
What does the aqueous humor do?
Nourishes the cornea and lens
What does the vitreous humor do?
Exerts pressure to maintain the shape of the eye
Define the limbus
The junction between the sclera and the cornea
Define canthi refer
Junction between the upper and lower eyelids
Where does the iris and posterior structures of the eye (with the exception of the lens) originate from?
Where does the lens and all the structures anterior to the iris originate from?
Embyonic ectodermal layer
What causes a coloboma?
Failure of the neuro-ectodermal tissue to wrap around the lens placode and fuse in a double layer inferiorly
What causes infantile glaucoma or buphthalmos?
Failure of the development of the iridocorneal angel and/or the Canal of Schlemm
Where does the nasolacrimal duct open into?
Inferior meatus of the nose
What secretes aqueous humor? Where is is located?
Ciliary body behind the iris
What is the circulation of aqueous humor?
drains through the pupil, then into the iridocorneal angle where it is reabsorbed into the Canal of Schlemm
What causes of aqueous humor drainage fails?
Increased intraocular pressure
Can cause retinal damage and blindness
Define ptosis. What can cause it?
Drooping of the eyelid.
CN III nerve palsy, sympathetic dysfunction (Horner's), neuromuscular disease (Myasthenia Gravis)
Define lid retraction
Patient will have wide eyed starring appearance. Superior sclera is visible on opening of the eyes fully.
Turning outward (sagging) of the eye margin.
It is often associated with aging.
There is a constant flow of tears down the medial side of the face.
Turning inward of the lid margin.
This can cause abrasion of the cornea.
Define a stye
Red, swollen and tender
Margin is red and irritated
Covered with scales
Define a chalazion
No acute signs of inflammation
Due to inspissated secretions of the mibomian glands
Discrete, waxy, yellowish deposit on the medial aspect of the lid
What are the signs of allergic reaction of the eye?
Pale, boggy swelling of all four eyelids
Fluid in the episcleral space
Whitish-yellow, triangular, nodular growth on the nasal portion of the bulbar conjuctiva adjacent to the corneal-scleral junction (limbus)
Does NOT invade the cornea
Similar in location to a pinguecula, but more vascular.
Begins at the medial canthus and extends beyond the corneal-scleral junction
Define arcus senilis
White ring in the cornea
< 40yo is a sign of hypercholesterolemia