Lecture 7: The Optic Nerve in Glaucoma

Question 1

List the 9 generalized signs of optic nerve damage

Answer 1

• Generalized enlargement c/d ratio
• Increased dept of cupping
• saucerization
• Vertical elongation of c/d ratio
• Cup-to-disc asymmetry
• Loss of neuro-retinal rim
• Peripapillary atrophy
• Laminar dot sign
• Pallor?

Question 2

List 2 localized signs of optic nerve damage

Answer 2

• Notching
• Acquired pit of the ON

Question 3

List 7 abnormalities of retinal vasculature

Answer 3

• Hemes of the NFL
• Focal narrowing
• Vascular attenuation
• Baring of circumlinear vessels
• Overpass cupping
• Nasalization of retina vessels
• Optic disc shunt vessel

Question 4

Larger discs have (larger/smaller) physiological cups

Answer 4

larger

Question 5

The more ellipitical discs have (more/less) elliptical cups

Answer 5

more

Question 6

optic disc is generally large in eyes with ____ and significantly smaller in eyes with marked ___.

Answer 6

high myopia; hyperopia (>+5)

Question 7

Optic disc size may vary with race. list from smallest to largest.

Answer 7

• Caucasians = smallest
• Mexicans
• Asian
• African americans = largest

Question 8

What is the normal optic disc size? What is the average size?

Answer 8

• Normal size: 1.33-2.66mm in diameter
• Average: 1.5

Question 9

Approximately ___ neurons enter ONH

Answer 9

1.2 million

Question 10

Why do we need to evaluate the RIM of the optic disc closely?

Answer 10

this is where nerve tissue is

Question 11

___ and ___ have higher predictive power than the neuro-retinal rim as a whole. Why?

Answer 11

• Inferotemporal and superotemporal
• Preferential loss of rim in these regions in medium to advanced stages of GON (Lamina distortion theory)

Question 12

______ of the cup is the most common type of change in progressive glaucoma. This disc change was found to preced VF loss by several years.

Answer 12

Generalized/concentric enlargement

Question 13

Concentric enlargement most often seen in ___, ___ and __ pt who convert to glaucoma

Answer 13

NTG, early POAG and OHTN

Question 14

T/F Depth is a specific finding for glaucoma. What is it affected by?

Answer 14

• False, it is NOT SPECIFIC
• Affected by
  
  • disc area
  • ethnicity, refractive error

Question 15

In advanced stages of glaucoma, the ON may demonstrate “bean potting”. What is bean potting?

Answer 15

• This relates to stress/strain & biomechanical principles applied to peripapillary sclera
• Beanpotting: retinal blood vessels disappear as they follow the lateral excavation of the optic cup and reappear at the bottom of the cup

Question 16

In normal eyes (Horizontal/Vertical) is larger than (Horizontal/Vertical)

Answer 16

horizontal is larger than vertical

Question 17

Vertical elongation develops secondarily to the loss of … ?

Answer 17

neuro-retinal rim at superior and inferior poles

• occurs less frequently than generalized enlargment of the cut BUT
  
  • more clinically significant; more easily diagnostic for glc
  • Can precede development of VF loss by several years

Question 18

Vertical Elongation: c/d ratio more than __ greater vertically than horizontally (this would naturally violate ISNT)

Question 19

What is focal notching?

Answer 19

Area of localized damage

• ​focal ischemia
• correlate with VF defects (structure & function relationship)
• May be preceded by drance heme
  
  • common in NTG
  • Typically at inferotemporal and superotemporal nerve
• May lead to vertical elongation

Question 20

Focal loss of ganglion cell axons usually at the ___ & ___ poles of ONH

Answer 20

superior temporal & inferior temporal

Question 21

Notching happens most often at the ___ pole & is consistent with which theory?

Answer 21

inferior; lamina distortion theory

Question 22

Notching usually produces scotomas in ____ area

Answer 22

Bjerrum area

Question 23

What is zone alpha? Is this a normal or abnormal finding?

Answer 23

• irregular pigmentation of RPE
• Normal finding

Question 24

What is zone beta?

Answer 24

• Atrophy of both RPE and choriocapillaris
• crescet like region where you can view choroidal vessels
• Progressive
• Can respond to areas of rim loss
• BUT NOT pathognomonic for glc

Question 25

List the area of progressive loss of rim in order

Answer 25

* Inferotemporal --\> * Superotemporal --\> * Temporal --\> * Inferonasal --\> * Supernasal --\>

Question 26

**Asymmetry of c/d between the eyes**: A difference of ___ or more is usually considered significant. A C/D difference of \>\_\_ exists in only \_\_% of normal eyes

Answer 26

0. 2 0. 2;1%

Question 27

If a person has an asymmetry of their ___ and overall ___ size, they wil lhave a physiological asymmetry (normal)

Answer 27

**scleral canals** and **overall ONH size**

Question 28

What is **laminar dot sign**? It is visiable in only \_\_% of myopic eyes

Answer 28

* exposure of laminar structure due to loss of neural tissue * laminar dots become more obvious in eyes with significant glaucomatous nerve damage * remember they are not completely specific to glc * **34%** * Represent holes in the lamina cribosa

Question 29

if lamina dots have a ___ or ___ shape, it may an indication of glaucoma

Answer 29

distorted or striate shape

Question 30

overall lamina dotes may indicate **_(mild/moderate/severe)_** glacuomatous damage and **striate slit** shapes may indicate more ____ glaucoma.

Answer 30

moderate; advanced

Question 31

T/F pallor in glaucoma is caued by loss of capillaries

Answer 31

**FALSE, it is NOT** * caused by increased visibility of supporting structures (e.g. sclera, CT, etc) due to enlargement of the cup

Question 32

Pallor is more typical of ____ optic neuropathy

Answer 32

non-glaucomatous

Question 33

Hemorrhage of NFL occur most frequently ___ and \_\_\_ * can be seen in any location * more prevalent in ___ glaucoma

Answer 33

temporally and inferotemporally NTG

Question 34

\_\_\_\_ is **highly** specific for glaucoma

Answer 34

flame shaped heme - vasospastic activity of retinal vasculature could lead to disc heme

Question 35

Heme of NFL VF changes can occur when?

Answer 35

weeks to months later * sig risk that VF changes WILL happpen following a drance heme - ominous

Question 36

focal narrowing of vessels occur where?

Answer 36

where cupping is most significant

Question 37

Why does focal narrowing occur?

Answer 37

less demand for blood supply because fewer ganglion cells to supply

Question 38

Arterioles should be widest where?

Answer 38

inferotemporal and superotemporal

Question 39

\_\_\_ is associated with overall loss of sensitivity VF testing

Answer 39

vascular attenuation

Question 40

Baring of circumlinear vessels occur in \_\_% normal eyes and \_\_% of eyes with glc

Answer 40

14%, 73%

Question 41

\_\_\_ is considered a "soft sign"

Answer 41

nasalizatio of vessels

Question 42

\_\_\_\_ vessels have a Z appearance due to sharpening of the border of the notch

Answer 42

bayonetic sign - rarely found in glaucomatous eyes * found in area of rim affected by focal notching

Question 43

The optic disc is best examined by \_\_\_

Answer 43

stereoophthalmoscopy