Ocular Lab 8 Questions

Question 1

Difference between ora serrata and peripheral retina

Answer 1

Ora serrata –> end of the retina

Peripheral retina –> outer part of retina that TERMINATES at ora serrata

Question 2

How wide is the macula

Answer 2

5mm

Question 3

Where the retina starts to make changes and slope

Answer 3

Fovea

Question 4

The very center of the fovea

Answer 4

Foveola

Question 5

What is the cup to disc ratio

Answer 5

Compares the diameter of the cup to diameter of entire disc

-> assess neuroretinal rim thickness over time

Question 6

How long is the intraocular part of ON

Answer 6

1.5 mm

Question 7

How long is the intraorbital part of ON

Answer 7

25mm

Question 8

How long is the intracanalicular part of ON

Answer 8

5 mm

Question 9

How long is the intracranial part of ON

Answer 9

10mm

Question 10

How long is the entire ON in length

Answer 10

4-5 cm

Question 11

Glial plaque (astrocytes) that line the optic cup

Answer 11

Meniscus of Kuhnt

Question 12

Peripheral continuation of meniscus of Kuhnt that lines surface of neuroretinal rim

Answer 12

Inner limiting membrane of elschnig

Question 13

Formed by footplates of muller cells, continuous with inner liming membrane of elschnig

Answer 13

Internal limiting membrane of retina

Question 14

Glial tissue that separates outer retina from bundles of ON fibers

Answer 14

Intermediary tissue of Kuhnt

Question 15

Collagen separating choroid from bundles of ON fibers

Answer 15

Border tissue of elschnig

Question 16

Glial tissue situated between border tissue of elschnig and bundles of ON fibers. it merges with intermediary tissue of kuhnt

Answer 16

Border tissue of jacoby

Question 17

Remnant of meniscus of Kuhnt tissue surround the hyaloid vasculature during development

Answer 17

Bergmeister’s papilla

Question 18

Size of small discs vertical diameter

Answer 18

<1.5 mm

Question 19

Size of large discs vertical diameter

Answer 19

> 2.2 mm

Question 20

Medium sized vertical diameter of optic disc

Answer 20

1.9mm

Question 21

Where does the ON become myelinated

Answer 21

Just posterior to lamina cribrosa

Question 22

What is the ON myelinated

Answer 22

For insulation, protection and to speed up travel/transmission to the brain

Question 23

What is the prelaminar diameter of ON

Answer 23

1.5mm

Question 24

What is the post laminar diameter of ON

Answer 24

3-4mm

Question 25

Why is there a difference in diameter between pre/post laminar regions of ON

Answer 25

Because of myelin being laid down behind lamina cribrosa

Question 26

What are the meningeal layers of the ON continuous with

Answer 26

The meningeal layers of the brain

Question 27

Bilateral swelling of disc caused by elevated intracranial pressure within the subarachnoid space

Answer 27

Papilledema

Question 28

Presents with indistinct margins of disc, engorged vessels, small peripapillary hemorrhages and loss of spontaneous venous pulsation

Answer 28

Papilledema

Question 29

Where does the intracanalicular portion of ON pass through and what travels with it

Answer 29

Lesser wing of sphenoid bone via optic canal with ophthalmic artery

Question 30

How does the ophthalmic artery sit in relegation to ON when passing through optic canal in lesser wing of sphenoid bone

Answer 30

Inferolateral to the ON

Question 31

How far from the globe does the CRA pierce the ON

Answer 31

1.25 cm

Question 32

What is the lamina cribrosa and adjacent pail plexus supplied by

Answer 32

Arterial circle of zinn-haller

Question 33

What supplies the arterial circle of zinn-haller

Answer 33

Short posterior ciliary arteries

Question 34

Why does the macula look different from the rest of the retina

Answer 34

- It only has densely packed cones, no rods - sloped bc of henle fibers - avascular - more than one RGCL - appears more pigmented bc less layers covering the RPE - high levels of carotenoids

Question 35

Why does the RNFL run parallel to retina

Answer 35

- axons of gang cells have to run this way to converge into ON - inline bipolar cells, they do not synapse locally, so their axons are different

Question 36

Why ON becomes thicker once the NFL passes through the lamina cribrosa

Answer 36

Bc of myelination

Question 37

3 main causes of papilledema

Answer 37

- inc CSF causing disc to be pushed forward - veins re engaged bc blood cannot leave eye - obstruction of axonal flow

Question 38

Total blood supply to the ON beginning with ICA

Answer 38

ICA -->. Ophthalmic a --> CRA --> capillaries and short posterior a

Question 39

Where does the CRA branch

Answer 39

In the intraorbital region after the optic canal

Question 40

Why are diabetics susceptible to ON damage

Answer 40

Bc the capillaries can be easily damaged

Question 41

Why is the optic disc taller than it is wide

Answer 41

Bc of ISNT rule | - more gang cells coming into top and bottom

Question 42

Why is the nasal side of ON thicker than temporal region

Answer 42

Temporal only gets in from from macular but nasal gets info form most of peripheral retina

Question 43

With the isnt rule, what is thickest/thinnest

Answer 43

I - thickest | T - thinnest