Right, Today we are going to continue the lectures on the structure of eye ball.
Already we have discussed cornea, sclera, right?
and we have also discussed the arterial supply to the eye ball.
Right?
Today we will specially talk about that uveal tract.
Right?
So.... let me very briefly review the basic structure of the eye ball and than we will
go into detail of the uveal tract.
As you know that basically eye ball has three main layers.
Right?
In which this is the outer most layer and this outer most layer is considered a protective
layer and this outer most layer of eye ball, its interior most area is transparent.
This is transparent and this is called cornea and this other part, this is white made of
collagen, its a tough membrane and this is called yes?
Sclera!
Very good!
Right?
So we can say the outer most layer or coat of the eye ball is protective part right?
Its posterior five sixth consists of sclera and interior you can say one sixth is basically
cornea which is transparent.
Right?
Am i clear?
Then!
Inside it, innter to this structure, inner to the sclera there is the main vascular layer
of the eye ball and this vasular layer of the eye ball, here I will make it just inside
the sclera, it extends on posterior surface, posterior area of the eye ball and it extends
interiorly.
Right?
Now this vascular layer of the eye ball.
Right?
or the middle layer of the walls of the eye ball, this thickens as it approaches interiorly,
it becomes thickened.
It becomes thick.
Right?
As it approaches interiorly and then this thickened part right?
Now this thickened part is called ciliary body and all vascular layer behind it is called
choroid and than there is a diaphram like structure but this is also vascular layer
and this interior most part is called.
This is a diaphram like structure with a central apperture, the apperture is called "Pupil"
and this part is called "Iris".
Is that right?
This is called "Iris".
Now, this is, yes! from here, from back upto here and here right all this structure is
yes?
Choroid.
This is called Choroid and this structure and this structure this is called cilliary
body and this part is called Iris.
Is that right?
This is called Iris.
Right? and all of this vascular layer is actually called "Uveal Tract".
So what is uveal; tract?
Uveal tract is basically middle coat of the eye ball wall and this is vascular coat, rather
I must say its vascular pigmented coat.
Its pigmented as well.
Right? and heavily vascular structure and this posterior five sixth of the eye ball,
this is basically choroid and than this yes enlarged part is called cilliary body this
diaphram like structure with a central apperture right?
This is called Iris.
Right? and inside it there is yes?
here the structure is yes please?
Retina.
Excellent!
This is called Retina.
Now!
As we will discuss later that retina has part in which this is having lots of rods and cones
right?
and a part of retina where rods and cones abruptly terminate at this point and this
point.
Rod and cones you can say abruptly terminate, the point of the retina where rod and cone
terminate this point is called "Ora Serrata".
What is it called?
Ora serrata! and a part of the retina, right?
It moves forward right?
the pigmented layer of the retina moves forward and it continues behind the Iris and cilliary
body and iris.
Now upto this point from here upto this point this is that part of the retina which is sensitive
to light and interior to this point right?
Part of the retina which extends forward it does not have rods and cones so it is called
that part of the retina which is not sensitive to the light and the point where these two
part of the retina meet with each other right?
the point where visual part of the retina or light sensitive part of the retina abruptly
terminates right?
That point is called Ora Serrata.
Am I clear uptill now? and than ofcourse you must be knowing that here is a structure called
yes?
Lens and behind the lens there is another structure here and this structure is called
Vitreous humor.
This is called Vitreous humor which is filling up the eye and lens is attached with special
ligament with the cilliary body and these ligaments of the lens which are holding the
lens or attaching the lens with the cilliary body these are called zonules or they are
called suspensory ligaments.
Is that right?
They are also called suspensory ligaments.
Any question about this?
No, so this is a very basic structure of the eye ball.
We have already studied the structure of the sclera, we have already lectures on the sclera,
we have also previously recorded lecture on cornea is that right?
and we have specifically had a very explanatory lecture on the blood supply to the eye ball.
Vessels which are supplying the eye ball.
I will briefly review that also because if blood supply to the eye ball is somewhat clear
than it will become very easy for you to understand the vascular supply within the uveal tract.
Again!
What is uveal tract?
Uveal tract is the vascular middle layer of the eye ball, is that right?
Uveal tract has posterior most part which is called choroid.
Than at ora serrata and forward uveal tract becomes thicker and that is called cilliary
body and than more interiorly uveal tract or this vascular layer becomes a diaphram
like structure with central apperture to allow the light to pass through that is pupil and
this diaphram like part, diaphram like curtain with a central apperture, this is called iris.
Is that right?
Any questions upto this?
Its clear?
Ok!
Now, very very briefly blood supply to the eye ball.
Right? and than we will continue our lecture on uveal tract.
Before I go for that you will tell me what is this structure now from here upto here?
Yes?
What is this structure?
Choroid.
What is this structure?
Cilliary body.
Excellent!
and what is this structure?
Iris, and all of this is uveal tract.
Am I clear?
and all of this is uveal tract?
Now the blood supply.
Right?
Very briefly.
Mainly the blood vessels which are coming to the eye ball, they are coming from opthalmic
artery.
Right?
From opthalmic artery number 1 artery goes here and this enters through the optic nerve
inside the eye ball and supplies the retina and this artery is called "Central Retina
Artery".
This is central retinal artery.
Right?
Then there are another group of vessels.
For example, I show it here that this will enter into eye ball outside the optic nerve
and this artery will yes here you see it is supplying which structure choroid.
What is this?
Blood vessel supplying choroid, and this blood vessel, right?
the first blood vessel was central retinal artery and number 2 blood vessel this and
this these are posterior cilliary arteries but they dont reach upto the interior part,
they dont reach upto the interior part of the uveal tract so we call them there are
posterior cilliary artery.
What are these?
Posterior cilliary artery and because they dont reach anterior most area they are considered
short, they are not long.
So what will be the name of this artery?
Short posterior cilliary artery.
Now the long posterior cilliary artery look at it, it comes from here it enters and it
moves forward forward forward and reaches upto here, its really long!
You see?
Posterior cilliary artery is mainly supplying choroid.
Posterior, short posterior cilliary, short posterior cilliary mainly supplying the choroid
and long posterior artery number 3 and you can put here also its the same so long posterior
cilliary moves forward and they are reaching upto here.
This is called what?
Long posterior cilliary.
Now listen!
This is posterior cilliary right?
This is also posterior cilliary but both of them are reaching not reaching to the cilliary
body and not reaching to iris so these are posterior short cilliary and these are entering
and reaching more interiorly so they are posterior long cilliary.
Is that right?
Am I clear?
Then!
here are the muscles, supplying the eye ball, attached with the eye ball and some opthalmic
artery branches go to the muscles and from the muscular sub branches enter what is this?
Enter into cilliary body, that is right.
This is muscular branch of opthalmic artery, from here a branch goes to the cilliary body
also, now this branch, this is also going to the eye ball, this is also going to the
eye ball, this is considered you can say number 4 and 4 this is considered anterior cilliary
artery.
This is considered anterior cilliary artery.
Any questions upto this?
Now you have to tell me.
What is this branch which through the optic nerve entering into eye ball and supplying
the inner most layer of retina.
What is this artery?
Yes?
Central retinal artery.
Now these are again branches which are entering from the back of the eye ball, so this is
posterior artery, sorry this one, the number 2, this is posterior artery, because its going
to eye ball, posterior cilliary artery but it is supplying mainly choroid and not supplying
the cilliary body and this is not supplying the iris, so this is short posterior cilliary,
short posterior cilliary, then this is an artery that also enters from the posterior
end of the eye ball.
Right?
It is posterior cilliary but it moves forward and it reaches upto cilliary body, right?
and its branches will supply the cilliary body and even to the iris.
So this is called posterior long cilliary artery.
You know the difference in short and long cilliary artery and than anterior cilliary.
Anterior cilliary artery is a branch of muscular branches of opthalmic artery and it enters
in the eye ball from anterior part, right?
Anterior to the middle, and anterior cilliary and once it enters in the cilliary body it
also makes anastomosis with the long posterior cilliary artery.
Am I clear?
This was a very brief review.
Now, we will go into detail of uveal tract, as you know already uveal tract consists of
three, what is uveal tract?
Its a vascular pigmented layer in the eye ball and its a middle layer because outer
layer is sclera, middle layer is uveal tract, out layer is cornea and sclera, middle layer
is uveal tract and inner most layer is retina.
Am I clear?
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