blood vessels of the eyeball

Question 1

what are the arterial supply arteries?

Answer 1

• long ciliary arteries
  -short ciliary arteries
  -anterior ciliary arteries (muscular arteries)
  *which are both branches of the OA

Question 2

veins involved in venous drainage?

Answer 2

• anterior ciliary veins (muscular veins)
• vortex veins
  -central retinal vein

Question 3

describe the long posterior ciliary arteries?

Answer 3

• 2 branches run anteriorly between sclera and choroid and join major arterial circle of iris
• supplies the ant. 1/2 of choroid + iris + ciliary body

Question 4

describe the anterior ciliary arteries?

Answer 4

• continuation of muscular branched to rectus muscles
• perforating branch, supplies major arterial circle of iris
  -episcleral branch anteriorly in conjunctival stroma , supplies conjunctiva, episcleral peripheral corneal arcades

Question 5

describe the short posterior ciliary arteries?

Answer 5

• forms ring of vessels around the optic nerve called circle of zinn-haller
• supplies the posterior 1/2 of choroid prelaminar & laminar portions of optic nerve

Question 6

describe the anterior ciliary veins?

Answer 6

• drain the following : iris, ciliary body, episcleral, conjunctival & ciliary body venous plexus, canal of schelmm

Question 7

describe vortex veins?

Answer 7

-drain the choroid and muscular veins

Question 7

what are the four different areas of optic nerve blood supply?

Answer 7

1. superficial nerve fiber layer
2. pre-laminar region
3. laminar region
4. retrolaminar region

Question 8

drainage of all regions of the optic nerve is from _____?

Answer 8

the central retinal vein

Question 9

where do the pre-laminar and laminar region get supply from?

Answer 9

short posterior ciliary arteries

Question 10

the blood supply in the ONH has _______ distribution

Answer 10

sectoral distribution

Question 11

why can the pattern of vision loss in the ONH vary?

Answer 11

the blood supply in ONH show inter-individual variation

Question 11

when are the pre-laminar and laminar region vulnerable to ischemia/hypoxia

Answer 11

if perfusion pressure drops since short posterior ciliary arteries & optic nerve head are end -arteries

Question 12

what are signs and symptoms of Ischemic Optic Neuropathies (AION)
Arteritic

Answer 12

• jaw claudication
  -headache, temporal pain
  -scalp tenderness
  -malaise
  *due to inflammation of the arterial lining leading to blockage of the optic nerve head blood supply

Question 12

what are signs and symptoms of Ischemic Optic Neuropathies (AION) NON-arteritic- AION

Answer 12

• painless loss of vision
• RAPD
• ONH swelling (acute phase)
  -Pallor ;paleness (late phase)
• otherwise normal fundus
• 90% of cases are NON-arteritic- AION

Question 13

what is the retinas dural (outer and inner) blood supply?

Answer 13

outer 1/3 supply = choriocapillaris (long and short posterior ciliary arteries –> drainage: vortex veins

inner 2/3 supply = intraretinal vessels (branches of central retinal A) –> drainage: central retinal vein

Question 14

what is FAZ

Answer 14

central 0.5mm region on fovea that lacks inner retinal capillaries & relies on choroidal circulation for nourishment

Question 15

what is the function of the Blood-Retinal Barriers?

Answer 15

controls metabolic exchange between the vasculature and the neural retina

Question 16

describe the outer Blood-Retinal Barriers?

Answer 16

-tight junctions between RPE cells
-choriocapillaris is fenestrated

Question 17

describe the inner Blood-Retinal Barriers?

Answer 17

-tight junctions between capillary endothelial cells (EC)
-inner retinal capillaries are continuous