6. Uveal Anatomy. Clinical Evaluation.

Question 1

what is the uvea ?

Answer 1

the vascular tunic of the eye
composed of the sclera
then the choroid -cillary muscle , iris
retina

Question 2

what is the macroscopic morphology of the iris ?

Answer 2

it is in front of the lens and divides the space in front of the lens to the anterior and posterior chamber

iris - divided into pupillary zone -
pupillary margin marked by a dark border known as the pupillary ruff - formed posterior pigment epithelium ending

a ciliary zone -
near the collarette - fuchs’s crypt the anterior limiting layer is absent
and few in periphery
cillary zone extends to cillary body

Question 3

what are the layers of the iris ?

Answer 3

anterior limiting layer - connective tissue , melanocytes (purpose of eye colour) and fibroblast
merge with cillary body

stroma - melanocytes , collagen , hyaluronic acid , vessels , nerves

muscular layer - smooth muscle at the pupillary margin
smooth muscle deep in iris stroma
sphincter pupillae more medial and dilator - lateral arriving from the anterior pigment epithelium of the iris
sphincter pupille is circularly located
and dilator papillae is more like rays

anterioir pigment epithelium -
basal surface - contractile smooth muscle process
continuation of the pigmented epithelium of cilliary body and retina

posterior pigment epithelium - curves around pupillary margin to form the pupillary ruff
continuation of non pigmented epithelium of only the cilliary body

Question 4

what is the function of the iris sphincter muscle ?

Answer 4

contract the pupil - miosis

Question 5

what innervates the iris sphincter muscle ?

Answer 5

parasympathetic system

short ciliary nerve from colliery ganglion containing all 3 characteristics

Question 6

what is the function of the dilator muscle ?

Answer 6

mydriasis - dilates
sympathetically innervated - long ciliary nerve
- nerves from the carotid plexus joining the ophthalmic nerve forming the nasocillary nerve branching of into the long colliery nerve

Question 7

what is the blood supply to the arteries ?

Answer 7

long posterior colliery artery which comes from the posterior aperture of the sclera forming major circle of iris

Question 8

what are the different types of fibres present in the colliery ganglion ?

Answer 8

parasympathetic - occulomotor nerve
sympathetic - from carotid plexus
and sensory - ophthalmic nerve

Question 9

the colliery body is brown in colour why ?

Answer 9

due to melanin pigment

Question 10

what is the colliery body ?

Answer 10

it is the forward attenuation of the choroid at ora serrata (the point where the retina is no longer attached to the ciliary body

Question 11

what are the areas of the colliery body

Answer 11

the anterior 2 mm part of the colliery body with the finger like projection - pars plicata

posterior 4 mm part which is smooth - pars plana

Question 12

what is the microscopic appearance of the cillary body

Answer 12

5 layers

supracilliary lamina - collagen fibres continuation of the suprachoroidal lamina
and the anterior limiting layer of the iris

stroma - common - connective tissue - fibroblast
cillary muscles - outer longitudinal
middle oblique
inner circular
vessels- major arterial circle of the iris
nerves
pigmented cells

pigmented epithelium - common
to iris

non pigmented epithelium -
low columnar cells
continuation of the sensory retina and continues as the posterior PIGMENTED LAYER OF THE IRIS

internal limiting membrane -

Question 13

what are the ciliary muscles ? and what is its function?

Answer 13

they are triangular in shape
non striated muscles
has 3 parts

1 outer longitudinal
2 middle oblique
3 inner circular

cillary muscle contraction - decrease the diameter of the ring of ciliary muscle
higher degree of accommodation required parasympathetic nerves dominant

Question 14

what is the nerve supply of the cilliary muscle

Answer 14

parasympathetic fibres from the colliery body arising from the oculomotor nerve - short ciliary nerves

receive sympathetic innervation from long colliery nerves - common from the carotid plexus to the ophthalmic nerve brach which is the nasocillary nerve and going into long colliery nerves with the sensory fibres of the ophthalmic nerve

Question 15

what are the colliery porcesses

Answer 15

it is beneath the iris root only arise from the pars plicata
they are white in colour
process is lined by two layers of epithelial cells - the core of it consist of blood vessels and connective tissues

Question 16

what is the function of the cillary body ?

Answer 16

pigmented ciliary epithelium secretes aqueous humour through the ciliary processes
vitreous humour produced by the non pigmented portion

posterior chamber and virtuous humour separated by the colliery body

zonular fibres connect the cillary body muscles to the lens allowing the ciliary muscles to alter the shape of the lens - accommodation

Question 17

what does the colliery body look like in cross section ?

Answer 17

triangular

Question 18

from where to where does the choroid extend to ?

Answer 18

from the ora serrata to the optic disc

Question 19

what are the microscopic layers of the choroid

Answer 19

suprachoroidal layer -outer surface is rough and lies in contact with the sclera
thin memebrane - collagen fibres , melanocytes and fibroblasts
continues with the supracilliary lamina

stroma - loose collagen fibres 
elastic and reticular fibres 
melanocytes
vessels arranged in three different layers 
layer of large vessel - hallers layer
layer of medium sized vessel - sattlers layer  
layer of choroicapillaries 
choroidal veins from vortex vein 

basal lamina/ bruch’s membrane lines with the pigment epithelium of the retina

Question 20

there is the space between the choroid and the sclera known as what?

Answer 20

suprachoroidal space - arteries and nerves

Question 21

blood supply to uveal tract ?

Answer 21

short posterior ciliary arteries
going into the suprachoroidal by perching the sclera and reaches the ciliary muscle as a bed of choriocapillaries
pierce the sclera around the optic nerve

the choriocapillaries drain via the vortex vein

long posterior ciliary artery
pierce the sclera a bit more diagonally not horizontally and make the hailers layer and supplying the choroid

anterior ciliary artery coming from the external ocular muscle piercing the sclera and going through supra choroidal space forming the major arterial circle in the colliery body supplying the iris and anastomoses with the long posterior ciliary artery

all arise from the ophthalmic artery