so have you ever heard of somebody having a stroke within their eye and in care we call them retinal
vein occlusions and in this video i'm gonna break down the pathogenesis of how it affects the eye
ultimately our vision and then the treatments for it that's today's video let's take a look.
hello and welcome this is dr Allen here from the dr eye health show helping you learn all about the
eyes and vision if you're new here to the channel definitely consider hitting that subscribe button
down below so you don't miss any of my future videos about eye care topics such as this one
in fact this is a huge shout out to many of the viewers who have requested this video specifically
for almost a full year and i apologize it took me this long to get to it but here it goes first
of all retinal vein occlusions are a pretty big topic in eye care both in optometry and
ophthalmology this is something we all have to learn and really know very well because it can
be a serious cause of vision loss and potentially other complications and issues within the eye
and oftentimes doctors will try to easily explain to their patients what's going on by just saying
that they had a stroke within their eye now there could be many things in the eye that could
be described as having a stroke this happens to be a vein occlusion or one of the veins in
the eye becomes occluded and then you have all these problems there's also artery occlusions
completely different thing we're gonna save that for another video sometime in the future but when
we talk about vein occlusions there's generally three types in eye care there's a central retinal
vein occlusion a hemicentral retinal vein occlusion and a branch retinal vein occlusion
you see the retina in the back of the eye is known to have a dual blood supply this means it
has arteries and veins that go through the optic nerve and into the eye and supply blood and oxygen
and nutrients to the front surface of the retina but then it also has another set of blood vessels
on the back of the eye through what is called the choroid now the veins that i'm talking about in
this condition these are the blood vessels within the retina that go through the optic nerve and
actually supply the anterior portion of the retina now depending on the location of the occlusion
it could be in the central retinal vein this is right where the blood vessels first
enter and exit the optic nerve going in and out of the eye then there's the hemi central retinal vein
occlusion which is a little bit more anterior to that but then you have a full branch retinal vein
occlusion this occurs more within the retina and has a very distinct look to it when someone has
a central retinal vein occlusion such as this the doctor will see a lot of blood throughout
the entire retina it affects all of the areas of the retina and oftentimes in school we learned to
recognize this as blood and thunder where somebody with a branch retinal vein occlusion this is where
the retinal vein that has a branch to it inside the eye that one is selectively occluded and
then it's just kind of a whole arm or section of that vein that's been blocked off such as in
this picture here where you can see the blood just kind of pooling in the retina just in one specific
quadrant i think by far in my practice i see branch retinal vein occlusions much more often and
central retinal vein occlusions coming just kind of close second but thankfully the pathogenesis
for all these conditions are very similar and i'll kind of want to break these down just so
that you understand what's happening within the eye now just for simplicity's sake let's go
over branch retinal vein occlusions first we call them brvo 's in the clinic and i like to describe
brvo's first to like students first because the brvo are a little bit simpler to understand
and the same pathogenesis that is affecting the branch retinal vein occlusion it can also be
applied to all other forms of vein occlusions now within the eye the central retinal artery and vein
they travel through the optic nerve and then they spread out into different quadrants of the eye you
have the superior temporal quadrant the superior nasal quadrant you have the inferior temporal
quadrant and the inferior nasal quadrant now when these blood vessels go out this direction they
both the artery in the vein they travel together and the artery crosses over on top of the vein
this is important to remember think of it like the different hoses that maybe you left out
for watering your lawn one summer the arteries are going to cross over on top of the vein and
what happens is that with age different lifestyle factors like inactivity people who don't exercise
and they have increased blood pressure people who eat really poorly who eat a lot of greasy burgers
and pizza as well as people who smoke they're at increased risk of developing what is called
arterial and arthrosclerosis arteriosclerosis is where the blood vessel that artery itself
the walls of it become thicker and more rigid and then atherosclerosis is where the cholesterol and
fatty plaques of your diet end up sticking on the inner lining of your blood vessels and this ends
up collecting and ultimately can become a plaque that blocks up the artery and that's what we call
a stroke and eventually a heart attack so all these different things kind of accumulate and
cause the artery which is again is running over on top of the vein to kind of swell up become
more rigid and thick and they share what is called an adventitial sheath that's where the artery and
vein cross over each other they share the same tissue and because the artery is getting thick
it starts to push on that vein causing the vein the amount of space for the blood to flow through
gets smaller and smaller and with that you create more turbulent blood flow within the vein
which that turbulence causes damage to the inner lining of the vein and we that inner line called
the endothelium because it gets damaged the body tries to repair it and with the repairing process
the new tissue the new endothelium isn't quite the same and ultimately with sustained increased
blood pressure and continued damage eventually it ruptures and that's when the blood breaks through
the vein and just spreads throughout the back of the eye now most commonly a branch rental vein
occlusion we will see in the superior temporal quadrant because there's more criss-crossing of
arteries and veins in that quadrant thankfully if you're young under the age of 50 your risk
of having one of these conditions is much lower there's still a possibility especially if you
have a hypercoagulability issue such as factor five Leiden that maybe runs in your family or
maybe you take some sort of birth control like if you're a woman you're taking birth control that
also carries a small risk of having a higher chance of one of these especially when you're
young and when an eye doctor sees this whether they're an optometrist or ophthalmologist they're
going to recognize whoa they have all this blood in the back of the eye they have a brvo
okay we have to think do they have perfusion do they have blood flowing to the retinal tissue
or not oftentimes in the clinic we can recognize white spots on the retina that we call cotton wool
spots that's often an indication that there is not perfusion and we call that ischemic branch
retinal vein occlusions or your doctor may order what is called a fluorescein angiogram which
is where they put a flourishing sodium dye through your arteries and veins and they take pictures of
the back of the eye and they can literally see where blood is still flowing within the retinal
tissues and in a brvo you can have the ischemic and non-ischemic versions the less blood flow or
more ischemic versions of a vein occlusion the worse the vision and the consequences within
the eye are going to be so people can have milder non-ischemic branch retinal vein occlusions that
they may not even notice that they have any vision changes or any sort of problems in the eye at all
or they can have very ischemic vein occlusions which ultimately lead to blank spots in their
vision and even blurred vision now ultimately what happens because of these retinal vein occlusions
how it affects your vision is that the retina itself is getting starved of oxygen and these
nutrients and so the retina starts to release these inflammatory proteins these inflammatory
mediators are going to cause the blood vessels around this kind of ischemic area that's not
getting its proper nutrients to it's gonna allow these blood vessels to start leaking
and with this increased leakage and perfusion of fluid from the blood vessels it's gonna cause
swelling this increased amount of fluid which is supposed to essentially kind of heal the eye
ends up causing kind of a blister formation within the retina and we call that macular edema and with
that it changes the architecture of the retina and you lose a lot of your eyesight your vision
becomes extremely blurry so if this doesn't happen if it's just a mild vein occlusion you may not
notice any difference in your visual acuity and that's why it's really important to still see your
eye doctor every year because they can often see that this happened maybe in the past maybe there's
some sort of indication that you had this a long time ago or perhaps they're catching one live
going on right now i remember a time during my residency i had a gentleman coming in just for a
pressure check for his glaucoma and i still looked inside of his eye to look at the optic nerve and
i could see he was having a vein occlusion right that moment so in that case i immediately said hey
sir you're having another issue that's unrelated to your glaucoma your visit's going to last a
little bit longer we went and checked his blood pressure and his blood pressure was alarmingly
high and that really takes me on to the treatment for something like a branch retinal main occlusion
now my job is to first recognize diagnose what is going on and also figure out if there is swelling
of the retina and ultimately guide kind of treatment and management for this disease
one of the big issues again like this gentleman that was in this story when i was at the VA
he had really high blood pressure so being that so much of this disease has to do with your blood
pressure your cholesterol potentially if you have diabetes other things like that it's important
that i manage and get this patient to be seen by a primary care physician their general practitioner
order appropriate blood work so that we know what's going on what are the risks
for potential stroke heart attack because that's life-threatening so in this particular case after
we knew that gentleman had high elevated blood pressure that day we also made a direct referral
to get blood work and then go see his family doctor so that he could get his blood pressure
under control now thankfully that gentleman that day still had 20 20 despite having a branch of
vein occlusion because his macula wasn't swollen at all he had essentially a non-ischemic branch
retinal vein occlusion but that gentleman we still had to watch him for several months because it's
possible it could have gotten worse he could have had macular edema that developed if you are
somebody whoever does develop vision changes from a vein occlusion such as a brvo when you have that
swelling you are going to be referred to a retinal specialist with a retinal specialist they will
again do that fluorescein angiogram so they know where the perfusion and non-perfusion is and then
they will offer different treatments most commonly today the first line of treatment are injections
of a medication known as the anti-VEGF which stands for vaso endothelial growth factor
and that's one of the special growth factors that's released from the retinal tissue when
there is inflammation and not enough kind of not enough nutrients and going to the retina itself
now i don't mean to scare people when i say you're gonna get an injection a needle going into the eye
but thankfully these treatments work amazing and oftentimes with repeated treatments and you're
close watching from your doctors they can get things under control and most people do have a
good visual prognosis after a vein occlusion like this most people do have vision better than 20/40
even if no treatment is given but even better when there is treatment and alongside the possible
injections for treatment for this sort of macular edema from a vein occlusion your doctor could
also recommend either laser or an injection of a steroid inside of the eye these have been kind of
older technologies and treatments that we've used however they can still be used in conjunction
with the anti-vegf injection again something that you'll have to leave open to discussion with your
retinal specialist and believe me they know what they're doing so if i was having this i would
just trust everything they say now in general these different treatments that i just described
those are the same treatments that we use for all forms of retinal vein occlusions the central
retinal hemi retinal vein occlusion it all happens for the same pathogenesis as the branch retinal
vein occlusion except it's at different locations within the eye however the central retinal vein
occlusion is a little bit more dramatic and has a higher risk of other complications one of those
big issues is a certain type of glaucoma that i want to kind of go over just a second what a
central vein occlusion is so i can better explain what might be going on with that type of glaucoma
now again the central retinal vein it's the central vein and so when that gets blocked off
the entire back of the eye looks completely filled with blood again blood and thunder is what we call
it in school that's what they train us to see and oftentimes this does come along with some sort
of uh macular edema so oftentimes when the doctor when your eye doctor sees this they're gonna
send you to a retinal specialist right away but it's also important for them to consider doing
a certain technique called gonioscopy this is a special type of contact lens that's placed onto
the eye after the eye's been numbed with some sort of eyedrop medication and then your doctor is able
to look through this special type of contact lens because it's got mirrors on it and allows us to
look at the angle structure of where the aqueous humor which is the fluid inside the eye that
controls the eye pressure we can see where the air that aqueous humor is draining out of the eye
this angle which is formed by the iris and then the cornea they come together at a certain spot
and that's where the fluid drains out of now what happens is because a central vein occlusion is so
dramatic there's really really no nutrient getting to the retina it's being starved very quickly
so new blood vessels start to grow inside the eye these new blood vessels which we call
neovascularization these new blood vessels can grow within the angle within that drain and that
means that there's nowhere for that aqueous humor fluid to go so the eye pressure starts to go up
really high and this can be a very serious form of glaucoma because that increased eye pressure
can push on the optic nerve and it can kill the nerve and once the nerve is dead bye-bye vision
and in eye care we call that 90-day glaucoma because within the first one to three months
that's when per a person's most at risk of developing this glaucoma from a central
retinal vein occlusion now the ultimate takeaway i hope you get from this video
is not just understanding the pathogenesis of retinal vein occlusion and its treatments but to
take advocacy for your own health if you're having vision changes make sure you see your eye doctor
and based on their recommendations follow whether they want you back in a month if they prescribe
you treatment make sure you follow that treatment they want what's best for you and your vision
and then second of all be an advocate for your health in regards to your blood pressure your diet
and your lifestyle in general if you're somebody who is already getting in your older age you're
over the age of 50 maybe you have not eaten a very well in your life if you eat a lot of greasy foods
cheeseburgers pizza and things like that that that's not necessarily good for your
body and if you're inactive if you're someone who doesn't exercise very much i know it can be
tough for a lot of us and something i'm working on but being active eating healthy not smoking
these all can contribute to having less chances of having a vein occlusion whether that's in one eye
or both eyes and it's overall going to reduce your chance of having a heart attack and stroke
and i think we can all agree those are all important things so if you liked today's video
going deeper into our eye health condition go ahead and smash that like button for me and leave
a comment in the section below of either your story involving something like a vein occlusion or
if you have another question about an eye health related topic or disease or treatment again drop
a question or comment in the section below because i read those comments and i would love to get back
to you and possibly make a video all about that topic otherwise if you are new here to the channel
make sure to hit that subscribe button down below so you don't miss any of my future videos again
this is dr joseph allen here from dr eye health keep an eye on it and we'll talk to you soon you