Ocular: Optic Nerve By OCT Flashcards

(63 cards)

1
Q

Optic nerve C/D ratio rarely differs between the two eyes by more than _______

A

0.1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

If there is a > 0.1 difference between the C/D ratio between the eyes, is this significant?

A

Yes, risk factor for Glaucoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Central depression representing absence of axons

A

Optic cup

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Lamina cribrosa pores often visible, especially in large cups are known as __________

A

Lamina dots

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Neuroretinal rim contains _________ and ________

A

RGC axons and glial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Having a large optic disc, means you will often have a ________ optic cup

A

Large

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Does having a large optic disc mean you will have more ganglion axons?

A

No, ganglion axons do not differ based on disc size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

RNFL thickness __________ with age w/ loss of _________

A

Decreases

Ganglion cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mean RNFL thickness in patients 5-15 years of age

A

107.6 +/- 1.2 um

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Mean RNFL thickness in patients 20-78 years of age

A

97.2 +/- 9.7 um

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Caucasian patients generally have the ________ Disc Area

A

Smallest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Patients of African descent have the _________ Disc Area

A

Largest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When magnification is accounted for: Hyperopic eyes above +4D have ________ discs

A

Smaller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When magnification is accounted for: myopic eyes with more than -8D have _________ discs

A

Larger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is considered a large Disc Area size?

A

Over 2.1 mm^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is considered a small Disc Area size?

A

Under 1.5 mm^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Magnification correction factor for 90D lens

A

1.3x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Magnification correction factor for 78D lens

A

1.1x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is considered a small disc vertical diameter?

A

< 1.5 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is considered an average disc vertical diameter?

A

1.5-2.0 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is considered a large disc vertical diameter?

A

> 2.0 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Vertical disc diameter is ________ than horizontal diameter

A

Greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Zeiss Cirrus OCT: utilizes consecutive radial _________ measurements along the nerve

A

BMO-HRW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

BMO

A

Bruch’s membrane opening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
BMO is an anatomic boundary of the _____________
Neuro-retinal rim tissue
26
BMO-HRW is the distance between _________ and _________ along the plane of the BMO
BMO and ILM
27
What is BMO-MRW?
- neuro-retinal rim thickness as the minimum distance between the BMO and ILM
28
MRW
Minimum rim width
29
The Heidelberg Spectralis OCT uses what BMO measurement?
BMO-MRW
30
What measurement is made perpendicular to the ILM and therefore is perpendicular to the axis of neural tissue as ILM and NFL are parallel?
BMO-MRW
31
What measurement does not take into account nerve fiber trajectory into the disc?
BMO-HRW
32
What measurement is made based off of the clinically visible disc margin?
DM-HRW
33
Macular axons travel towards the nerve as a __________ bundle
Papillomacular bundle
34
RGC axons from the nasal half of the retina travel where?
Directly towards the nerve
35
RGC axons from areas of retina temporal to the fovea travel in what way? What are these bundles of axons called?
Arc around the fovea to the nerve ## Footnote Called arcuate bundles
36
RNFL thickness can be plotted horizontally as __________ or __________
TSNIT or NSTIN
37
Is TSNIT or NSTIN becoming increasingly more common?
NSTIN due to temporal RNFL being in the middle of
38
In the RNFL thickness plot, what are the 2 main bundle peaks known as the double hump on a healthy RNFL horizontal plot?
Supero-temporal ## Footnote Infero-temporal
39
Normal order of descending thickness of RNFL
ISNT
40
Retinal vessels develop along peak _________ densities
Ganglion cell
41
What is a good filter to use to visualize the RNFL?
Red-free filter
42
Peak RNFL bundles in high myopia are _________ and shifted ___________
Straightened and shifted temporally
43
In instruments that do not correct for patients refractive error, how are RNFL bundles shifted in high myopia? This non-correction can lead to a so called 'disease' known as __________
Shifted temporally ## Footnote Red disease
44
What are the two secondary RNFL bundle peaks? And what do they correlate with?
Supero-nasal ## Footnote Infero-nasal Correlate with nasal retinal vessels emerging from disc
45
RNFL is thinnest at the disc where?
Temporally
46
RNFL is overall thinnest in what region? And why?
In the fovea where there are no RGC axons
47
Disc-Fovea angle range is from ________ and __________
-20º and +9º
48
Disc-Fovea angle is about _______ degrees on average
-6
49
Do disc-fovea angles vary between the eyes of a patient?
Yes, they can
50
Abnormal disc-fovea angles that are not compensated for by OCT can lead to false positives for __________
RNFL thinning
51
With Excyclotorsion, how are the RNFL bundles shifted? And why?
Shifted temporally due to the very negative disc-fovea angle
52
A very positive disc-fovea angle will shift _______ peak RNFL bundle in which way? (Relative to database)
Very positive disc-fovea angle will shift inferior peak RNFL bundle temporally
53
A large portion of ganglion cells are concentrated where?
In the macula
54
Why do we measure ganglion cells thickness?, why is it important?
RGC dendrites die FIRST, then cell bodies, then axons ## Footnote Can detect damage sooner when looking at ganglion cells thickness
55
Topcon's Maestro (SD-OCT) measures 2 different ganglion cell layer thicknesses: what are they?
GCL + ## Footnote GCL ++
56
GCL+ is measurement of what thickness?
Ganglion cell and inner plexiform layer thickness
57
GCL ++ is measurement of what thickness?
Ganglion cell, inner plexiform and retinal nerve fiber layer thickness
58
Topcon's Triton SS-OCT Retina thickness measurement is between what boundaries?
The ILM-OS/RPE boundaries
59
Topcon's Triton SS-OCT RNFL thickness measurement is between what boundaries?
The ILM-RNFL/GCL boundaries
60
Topcon's Triton SS-OCT GCL+ thickness measurement is between what boundaries?
The RNFL/GCL-IPL/INL boundaries
61
Topcon's Triton SS-OCT GCL++ thickness measurement is between what boundaries?
The ILM-IPL/INL boundaries
62
Temporal raphe divides the temporal RNFL into _________ and _________
Superior and inferior halves
63
Why is glaucomatous damage often asymmetric across the horizontal midline? And what is this sign called?
Due to the superior and inferior segregation of nerve fibers into the disc. ## Footnote Temporal Raphe sign. Helps differentiate glaucoma vs. non-glaucoma issues