Pathophys - Glaucoma Flashcards
glaucoma is defined as a group of ___ disorders, that results in what?
eye disorders
results in damage to the OPTIC NERVE and often leads to blindness/complete loss of sight
true or false
glaucoma often results in damage to the capillaries of the eyes, leading to complete loss of sight
FALSE - damage to the optic nerve
true or false
glaucoma is not lethal
true - it is disabling bc it can cause blindness, but not lethal
TRUE OR FALSE
vision loss resulting from glaucoma is permanent and cannot be reversed
true
WHY is it that vision loss from glaucoma is permanent?
because there is damage to neurons and they can’t regenerate themselves
3-4 eye disorders that exist are the result of what?
high pressure in the eye
causing damage to the retina and optic nerve, leading to blindesss
name the 3 classifications of glaucoma
open angle/wide angle
closed angle
congenital
another name for open angle glaucoma
wide angle glaucoma
of the 3 classifications of glaucoma, which is most common?
open angle/wide angle glaucoma
differentiate between the drainage from the eye in open angle vs closed angle glaucoma
in open angle, the drainage from the eye remains open
in closed angle, the fluid drainage from the eye is BLOCKED
Differentiate between open and closed angle glaucoma based on how quickly vision is lost, and if pain exists
in open angle, there is a GRADUAL LOSS of peripheral vision. it develops slowly and there’s no pain
in closed angle, it usually presents rapidly (but can be gradual) and there is SEVERE EYE PAIN
in open angle glaucoma, there is a GRADUAL LOSS of peripheral vision, and ______ vision loss develops
central
true or false
closed angle glaucoma develops slowly with no pain
FALSE - this is open angle
are there any chromosomes/genes that seem to be linked to open angle glaucoma
yes
true or false
in closed angle glaucoma, fluid drainage from the eye is blocked
true
name some physical manifestations of CLOSED ANGLE glaucoma
severe pain
blurred vision
pupil is dilated
eye is red
nausea
why is nausea a common symptom of closed angle glaucoma?
because of the imbalance between the sensory input of the eye and ear
congenital glaucoma is also known as…..
infantile glaucoma
what is the cause of congenital glaucoma?
due to development abnormalities, there is obstruction of aqueous humor drainage
is congenital glaucoma a sex-linked disorder?
yes - X-linked recessive
as mentioned, congenital glaucoma presents in an X-linked recessive pattern
what does this mean?
it is more common in MALES (65%)
true or false
congenital glaucoma can be sex-linked as well as gene linked
true
true or false
glaucoma can occur as a result of mutated genes.
these genes seem to be different from open and closed angle glaucoma
true
true or false
low blood pressure seems to be a risk factor for developing glaucoma
FALSE
high blood pressure (glaucoma is associated with increased pressure in the eye) - or ocular HTN
true or false
congenital malformations are a risk factor for glaucoma
TRUE
such as congenital malformations in the trabecular network
being of _________- ancestry seems to be a risk factor for glaucoma
east asian
the eyeball is divided into _______ segments by the ______
what are these segments called?
divided into 2 segments by the LENS
called the anterior and posterior segment
true or false
the anterior segment is in front of the lens and filled with a gel-like vitreous humor
FALSE - it’s in front of the lens, but filled with AQUEOUS HUMOR (more watery)
where is the posterior segment located and what is it filled with
behind the lens
filled with vitreous humor – more gel like and viscous
how can the anterior segment be divided?
divided by the IRIS into the anterior and posterior CHAMBER
true or false
tears are not aqueous humor
true
true or false
the anterior segment is filled with aqueous humor
true
what produces aqueous humor?
how often?
the ciliary body – produces aqueous humor continuously
as the ciliary body is continually producing aqueous humor, where does it flow into?
explain full flow
into the posterior chamber, then flows into the anterior chamber through the pupil/iris
it then drains from the anterior through the TRABECULAR NETWORK, and then into the blood via the canal of schlemm (or scleral venous sinus)
the aqueous humor flows from the posterior chamber into the anterior chamber through…….
the iris, or more specifically pupil
as mentioned, aqueous humor flows from the posterior chamber into the anterior through the PUPIL
from this anterior chamber, where does it go and how?
first enters the trabecular meshwork in the corner of the eye, and then through the canal of schlemm —— into the BLOOD
the composition of aqueous humor is similar to what?
blood plasma
true or false
the aqueous humor formed by the ciliary process first flows into the anterior chamber
FALSE - posterior, then into anterior through the pupil
the posterior segment is located behind the _______
lens
what is located within the posterior segment that gives structure to the eye?
the vitreous chamber, filled with vitreous humor (gel like)
what is the vitreous humor composed of
collagen fibrils + water
_________ is a viscous ground substance that has a lot of water and contributes to the structure and intraocular pressure of the eye
vitreous humor
explain the pathophysiology of open angle glaucoma
there is reduced flow of aq humor through the trabecular meshwork either because of degeneration and/or obstruction of the network
this reduction in trabecular flow leads to an increase of intraocular pressure because the ciliary process is continually producing aqueous humor and it’s not draining properly from the anterior chamber
the aq humor then builds up in the anterior segment. this pressure extends to the retina and optic nerve and sight is affected
explain the pathophysiology theory of CLOSED ANGLE glaucoma
the channel between the anterior and posterior segments is COMPLETELY CLOSED due to the lens being pressed against the iris — displacement of the iris against the corna
aq humor can’t flow from the posterior and into the anterior chamber
this causes a buildup of aq humor in posterior chamber, causing pressure and pain in the posterior segment, extending to the retina and optic nerve
what causes the complete blockage of flow from posterior to anterior chambers being completely closed
displacement of the iris against the cornea.
flow is blocked
explain the effects of increased intraocular pressure in the eye
cupped excavation of optic nerve head – also retina will physicall change shape
cornea or sclera bulges at weak point, affecting vision and focus
optic nerve atrophy – loss of axons and glial cells (gliosis)
plial septa thickens
vision declines with the loss of neurons
what is the result of loss of axons and gliosis that occurs as a result of increased IOP?
can’t transmit action potentials
scar on optic nerve is formed
what are the 2 structures in the eye most crucial for taking in light, and damage to them can lead to permanent blindness, as seen in glaucoma
retina and optic nerve
true or false
closed angle glaucoma is usually associated with more rapid vision loss and pain, as compared to wide angle
true
explain the cause of neuron loss and loss of sight in glaucoma
bc of damage to the nerves at the head of the optic nerve, the retina degenerated – specifically the ganglionic and nerve layers
this impairs vision
name the receptors in the retina
rods and cones
