other structures in eyeball + vasculature + clinical Flashcards
what are the structures not located within the eyeball in the eye?
These are the lens and the chambers of the eye
where are the lens of the eye located?
located anteriorly, between the vitreous humor and the pupil
what is the shape of the lens altered by?
by the ciliary body, changing its refractive power
within vascular layer
what is cataract?
In old age, the lens can become opaque
what are the 2 fluid filled areas in the eye known as?
anterior and posterior chambers
where is the anterior chamber located?
between the cornea and the iris
where is the posterior chamber located?
between the iris and ciliary processes
what are the anterior and posterior chambers filled with?
The chambers are filled with aqueous humor
what is aqueous humor?
a clear plasma-like fluid that nourishes and protects the eye
when is aqueous humor produced?
produced constantly
where does aqueous humor drain?
drains via the trabecular meshwork, an area of tissue at the base of the cornea, near the anterior chamber
what happens if the drainage of aqueous humor is obstructed?
a condition known as glaucoma can result
what does glaucoma refer to?
a group of eye disease that result in damage to the optic nerve
what are the two main clinical classifications of glaucoma?
open angle
closed angle
what is open angle glaucoma?
the outflow of aqueous humor through the trabecular meshwork is reduced
what does open angle glaucoma cause?
gradual reduction of the peripheral vision, until end stages of the disease
what is closed angle glaucoma?
the iris is forced against the trabecular meshwork, preventing ANY drainage of aqueous humor
what is closed angle glaucoma a type of? lead to?
opthalmic emergency, can rapidly lead to blindness
where does the eyeball receives arterial blood primarily via?
ophthalmic artery
what is ophthalmic artery a branch of?
the internal carotid artery
where does ophthalmic artery arise?
immediately distal to the cavernous sinus
what does the ophthalmic artery give rise to?
many branches, which supply different components of the eye
which is the most important branch of the ophthalmic artery?
The central artery of the retina
what does the central artery of the retina supply?
the internal surface of the retina
what can occlusion of the internal surface of the retina lead to?
quickly result in blindness
what carries out the venous drainage of the eyeball?
the superior and inferior ophthalmic veins
where do the superior and inferior ophthalmic veins drain into?
the cavernous sinus, a dural venous sinus in close proximity to the eye
what does papilloedema refer to?
a swelling of the optic disc
when is papiloedema visible?
during ophthalmoscopy
what is the optic disc?
the area of the retina where the optic nerve enters.
what is opthalmoscopy?
a visual inspection of the eye using an ophthmoscope
what does papilloedema arise due to?
The swelling occurs secondary to raised intra-cranial pressure
why does papilloedema arise secondary to raised ICP?
The high pressure within the cranium resists venous return from the eye. This causes fluid to collect in the retina, producing a swollen optic disc.
