Lecture: Optic Nerve

Question 1

What side of the eye is the optic nerve always on?

Answer 1

Nasal side

Question 2

What does the ora serrata look like both temporally and nasally?

Answer 2

Temporally = sort of flatter, kind of like waves
Nasally = knife like, with very sharp processes

Question 3

What part of ganglion cells reach out into the Inner Plexiform Layer (IPL)?
What parts reach down into the Nerve Fiber Layer (NFL)?

Answer 3

IPL = Dendrites
NFL = Axons

Question 4

About how many retinal ganglion cells reside in the retinal ganglion cell layer (RGCL) in the adult retina?

Answer 4

1.2 to 2.2 million

Question 5

Output cells (3rd order neuron) of the retina that convey all of the processed visual information to the brain

Answer 5

Retinal ganglion cells

Question 6

Formed by the axons of the retinal ganglion cells

Answer 6

Retinal nerve fiber layer

Question 7

Diameter of optic nerve fibers

Answer 7

1 um (1 micrometer), while a small percent have diameters as large as 2-10 um (micrometers)

Question 8

Where is the superficial layer located?

Answer 8

Nerve fiber layer (NFL)

Question 9

Where is the deep layer located?

Answer 9

In the inner limiting membrane (ILM)

Question 10

Average size of macula

Answer 10

5.5mm

Question 11

Nerve fiber tract of the central nervous system; prone to many of the same neurological disease (i.e., multiple sclerosis)

Answer 11

Optic nerve (cranial nerve II)

Question 12

What can make multiple sclerosis more noticeable

Answer 12

Small changes in temperature

Question 13

4 divisions of the optic nerve, anterior to posterior

Answer 13

1) intraocular
2) intraorbital
3) intracanalicular
4) intracranial

Question 14

Length of the optic nerve?

Answer 14

4-5 cm (it’s not taught. It slacks a little bit so it doesn’t get severely damaged if it is pressed on)

Question 15

What characteristics do you look for in the optic nerve?

Answer 15

Contour (sharp border)
Color (white, pink, yellow?)
Size (small or large)
Lamina cribrosa

Question 16

The optic disc is longer in which dimension?

Answer 16

Longer in the vertical dimension vs the horizontal dimension

Question 17

Vertical dimension of the optic disc

Answer 17

1.9 mm

Question 18

Horizontal dimension of the optic disc

Answer 18

1.5 mm

Question 19

The optic cup is displaced slightly _____ from the center of the disc, and is devoid of ______.

Answer 19

• temporal

- nerve fibers (axons)

Question 20

Foramen that is occupied by axons of retinal ganglion cells and lamina cribrosa

Answer 20

Posterior scleral foramen

Question 21

Contains nerve fibers and is located between the margin of the optic disc and cup

Answer 21

Neuroretinal rim

Question 22

Thickest to thinnes quadrants of the neuroretinal rim

Answer 22

ISN’T

Inferior, Superior, Nasal, Temporal

Question 23

What does the cup to disc ratio compare? What is is used for?

Answer 23

The diameter of the cup with the overall diameter of the optic disc
Used to assess changes in neuroretinal rim thickness over time

Question 24

Which blood vessels emerge from the optic cup? In which location of the optic cup do they emerge?

Answer 24

Central retinal blood vessels (artery and vein)

Emerge from he nasal side of the cup

Question 25

What 3 layers make up the intraocular portion of the optic nerve?

Answer 25

Retinal layer
Choroidal layer
Scleral layer (Lamina cribrosa)

Question 26

Relative to the lamina cribrosa, the intraocular part of the optic nerve can be divided into which 2 parts?

Answer 26

Pre-laminar

Laminar

Question 27

As IOP increases, what happens?

Answer 27

Pushes on the lamina cribrosa, making it bow out, which can make it pinch the vessels that are running through it

Question 28

What is the vision at the center of the optic nerve?

Answer 28

0 b/c it is the blind spot

Question 29

The optic disc is located in this layer because it is the atonal fibers of the retina ganglion cells that converge to form it

Answer 29

Retinal layer

Question 30

Layer of the optic nerve at the level of the choroidal tunic

Answer 30

Choroidal layer

Question 31

What begins at the outermost portion of the choroidal layer of the optic nerve? Where does it continue?

Answer 31

Lamina cribrosa

Continues into the scleral layer of the optic nerve

Question 32

Pre-laminar portion of the optic nerve comprises which 2 layers?

Answer 32

Retinal layer and choroidal layer

Question 33

Glial border that is like a glial plaque, covering the cup; What type of glial cells are located here?

Answer 33

Meniscus of Kuhnt

Astrocytes

Question 34

Continuous with the inner limiting membrane of the retina

Answer 34

Inner limiting membrane of Elschnig

Question 35

Glial plaque (astrocytes) that lines the optic cup

Answer 35

Meniscus of Kuhnt

Question 36

Peripheral continuation of Meniscus of Kuhnt that lines surface of neuroretinal rim (astrocytes and glia)

Answer 36

Inner limiting membrane of Elschnig

Question 37

Formed by footplates of Muller cells, continuous with Inner Limiting Membrane of Elschnig

Answer 37

Internal Limiting Membrane of Retina

Question 38

Glial tissue that separates outer retina from bundles of optic nerve fibers

Answer 38

Intermediary tissue of Kuhnt

Question 39

Glial borders that are associated with retinal layers

Answer 39

Meniscus of Kuhnt
Inner limiting membrane of Elschnig
Intermediary Tissue of Kuhnt
Internal Limiting Membrane of Retina

Question 40

Glial borders that are associated with choroidal layers

Answer 40

Border tissue of Elschnig

Border tissue of Jacoby

Question 41

Collagen separating choroid from bundles of optic nerve fibers

Answer 41

Border tissue of Elschnig

Question 42

Glial tissue situated between border tissue of Elschnig and bundles of optic nerve fibers. It merges with (5) intermediary tissues of Kuhnt.

Answer 42

Border tissue of Jacoby