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Ocular Disease II > Glaucoma: Optic Nerve > Flashcards

Glaucoma: Optic Nerve Flashcards

1
Q

Optic Nerve Damage

  1. Cupping: What is it?
A
  1. Loss of NEURAL TISSUE w/subsequent INCREASE in size of the OPTIC CUP (FUNDAMENTAL PROCESS of glaucoma)
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2
Q

Anatomy of the Optic Nerve: 4 things?

A
  1. Cup, Lamina Cribrosa, Rim, Vessels
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3
Q

Optic Nerve: Rim

  1. Ganglion cell Axons make up what % of the Neuroretinal Rim Tissue?
  2. Where are the axons from?
  3. How do they travel thru the Retinal NFL?
    a. They Make what kind of turn? And Remain where?
  4. ONH: Axons are grouped into about how many bundles?
A
  1. 90%
  2. Receptor Fields found throughout the retina
  3. In an ORGANIZED Pattern
    a. At the Optic disc, they make a 90 degree turn and remain along the outer edge of the optic disc
  4. Into about 1000 bundles that pass thru fenestrations in the Lamina Cribrosa
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4
Q

Optic Nerve: RNFL

  1. RNFL from Temporal Periphery Originates where?
  2. RNFL From CENTRAL Retina, Papillomacular Bundle, and Nasal Fibers take what route?
  3. This is IMPORTANT for what reason?
  4. Fibers originating from Peripheral Retina Run how?
  5. Fibers Originating Nearer to the ONH are situated where?
A
  1. on Either Side of the HORIZONTAL RAPHE and then Arch around the Fovea
  2. a More direct route to the ONH
  3. For understanding Types of Glaucomatous VF Loss!!!
  4. run closer to CHOROID and Periphery of Optic Nerve
  5. Closer to the VITREOUS and OCCUPY a more central portion of the Nerve
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5
Q

Optic Nerve: Rim: Blood Capillaries!

  1. Arterial Supply?
  2. In Glaucoma, with Ganglion cell loss, what happens with capillaries?
  3. Other Optic Neuropathies will cause what?
A
  1. POSTERIOR CILIARY ARTERY w/exception of RNFL (Central Retinal Artery supplies that)
  2. PROPORTIONAL LOSS OF CAPILLARIES thus maintaining an ORANGE-RED APPEARANCE in the REMAINING NEURORETINAL RIM TISSUE! *UNIQUE to GLAUCOMA
  3. PALLOR in the Neuroretinal Rim Tissue
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6
Q

Optic Nerve: Pale Cupping

  1. If nerve is pale, what 3 things should you think about?
  2. CLINICALLY IMPORTANT: Glaucoma is what kind of a disease (progressive/non progressive)?
    a. How does this tidbit help you distinguish b/w other optic neuropathies?

b. When does the Neuroretinal Rim have the Appearance of Pallor

A
  1. CIN (Compression Lesion, Ischemic Vascular Accident, Neurologic Event)
  2. Progressive
    a. Most others may not be progressive or may not require treatment!!
    b. END STAGE GLAUCOMA, when Collagenous Lamina Cribrosa is MORE EXPOSED!
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7
Q

Optic Nerve: Glial Cells and Astrocytes

  1. Provide structural support to Axons: Which area has the LEAST STRUCTURAL SUPPORT?
    a. What does this mean in regards to Glaucoma and C/D Ratio?
A
  1. Axons in Sup and Inf poles of Optic Nerve.

a. Predisposed to glaucoma damage = Suspect Glaucoma with VERTICALLY ELONGATED C/D RATIO

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8
Q

Optic Nerve: Lamina Cribrosa

  1. What is it?
    a. Is it the Weakest or Strongest Area of Outer Connective Tissue Tunic?
  2. So what happens in glaucoma with ganglion cells: where are they dying at?
A
  1. Posterior Scleral Foramen; Network of Collagen lined w/ASTROCYTES to make CANALS where the OPTIC NERVE BUNDLES EXIT!!!
    a. WEAKEST. ( May be most susceptible to INCREASED IOP: Astrocytes specifically)
  2. At their AXONS at LEVEL of LAMINA CRIBROSA then RETROGRADE ATROPHY to their Cell Bodies!
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9
Q

Optic Nerve: Lamina Cribrosa (Scleral Foramen)

  1. Large Scleral Foramen means what to the DISC?
A
  1. Means LARGE PHYSIOLOGIC DISC! (Scleral Foramen can vary from 1-3 mm)
    * Larger disc tends to have MORE AXONS than smaller discs!
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10
Q

Glaucomatous Optic Atrophy

  1. 3 Things to look at? Within each of these, what are signs of Glaucoma?
A
  1. Disc Patterns
    a. Atrophy/Notching
    b. Deepening of Cup
    c. Pallor-Cup Discrepancy
    d. Advanced Glaucomatous Cupping
  2. Vascular Signs
    a. Disc Hemorrhages (Drance Hemorrhage)
    b. Vessel Appearance
    c. Central Retinal Artery Trunk
  3. Peripapillary Changes
    a. RNFL Defects
    b. Atrophy
    c. Hemorrhages
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11
Q

Optic Nerve: 5 Rs

  1. What are they?
    a. Correction Factors for lenses
A
  1. Scleral RING (Purpose: find it to figure out Physiologic Disc Size)
    a. 60D: 1.0; 78D: 1.1; 90D: 1.3
  2. Size of RIM
  3. RNFL
  4. Region of PPA
  5. Retinal and Optic Disc Hemorrhages
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12
Q

Optic Nerve: 5 Rs

  1. Scleral Ring
    a. Disc size is independent of RF b/w -5D and +5D. What if you’re above that?
    b. Ethnicity?
  2. Size of RIM
    a. What is the Neuroretinal Rim Width?
    b. Contour vs. Color?
    c. Rule?
  3. CUP
    a. Avg C/D Ratio?
    b. Size b/w 2 eyes?
    c. C/D >0.2 b/w the eyes is Normal?
A
  1. > +5D = Smaller optic disc relative to Emmetropic Eyes
    Sup > Nasal > Temporal)
  2. a. 0.4
    b. Should be symmetrical
    c. No. 24% in POAG; Basically, if cup is symmetrical, BUT there is a SIZE DIFFERENCE of >0.2 C/D Ratio b/w the 2 EYES, MONITOR FOR GLAUCOMA!!
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13
Q

Optic Nerve: 5 Rs

  1. Cupping: Other diseases can cause “cupping” but there are features INCONSISTENT with GLAUCOMA: What are they?
A
  1. VAs, Color Vision, RAPD, VF Defects, Disc Appearance (Pallor)
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14
Q

Optic Nerve: 5 Rs

  1. Rim Tissue Notching
    a. What is it?
    b. Associated with what 2 things?
  2. Glaucoma Suspicion (Rim Tissue and Vasculature Eval)a.
    a. Central Retinal Vessel Trunk
    b. Vessel Baring
    c. Vessel Bayoneting
A
  1. a. Loss of local areas of Ganglion cell axons, causing LITTLE TO NO REMAINING RIM TISSUE IN A FOCAL AREA OF THE OPTIC NERVE!
    b. VF Defect and RNFL Defect!
  2. a. Longer distance to Central Retinal Vessel Trunk Exit, the more marked the Neuroretinal Rim and VF LOSS (Cupping past the vascular trunk)
    b. Horizontal vessels are not supported by rim tissue and are suspended in free space.
    c. Vessels deviate from Normal Course due to FOCAL NOTCHING (Z Appearance)
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15
Q

Optic Nerve: 5 Rs

  1. Pallor-Cup Discrepancy
    a. EARLY Stages of glaucoma: CUP ENLARGEMENT MAY PROGRESS AHEAD OF WHAT?

b. What is SAUCERIZATION?

A
  1. of Pallor (different from other Optic Neuropathies cuz Pallor is usually LARGER than the CUP)
    b. Pattern of Early Glaucomatous Change where diffuse, shallow cupping extends towards the disc margin w/retention of a central pale cup. (HARD TO DETECT: Contour vs. COLOR when looking at C/D Ratio)
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16
Q

Optic Nerve: 5 Rs

  1. Advanced Glaucomatous Cupping
    a. WHat is it?

b. Clinically?
c. BEAN POTTING: Define?

A
  1. a. Loss of ALL NEURAL RIM TISSUE (total cupping)
    b. White disc w/loss of all rim tissue and VESSELS VENDING at MARGIN of DISC
    c. Cupping due to CROSS SECTION of OPTIC NERVE showing EXTREME POSTERIOR DISPLACEMENT of the LAMINA CRIBROSA

(Retinal BVs disappear as they follow the excavation of the Optic Cup and Reappear at the Base of the CUP: Sign of End STAGE of the DISEASE)

17
Q

Optic Nerve: 5 Rs

  1. RNFL Evaluation
    a. No pathology?
  2. Defects?
A
  1. a. Bright Striations (most are “Shiny”) where RNFL is thickest! (Sup Temp and Inf Temp); Obscured Vasculature margins; Visibility of RNFL DECREASES with AGE! (loss of about 4000-5000 fibers/year)
  2. 20% of Glaucoma Eyes. Increases significantly from early to mod disease. (Cant detect it in advanced disease as loss is pronounced in all areas).
    * Usually INFERIOR TEMPORAL then Superior TEMPORAL
    * RNFL Loss can be Diffuse (General reduction in RNFL Brightness), Local (Wedge Shaped Dark Areas stemming from the disc following Anatomy), or mixed pattern.
    * Vasculature can become MORE DISTINCT due to LOSS of RNFL!
18
Q

Optic Nerve: 5 Rs: Peripapillary Region Eval

  1. What is the area?
  2. What is it?
  3. 2 ZONES: What are they
A
  1. Area Adjacent to Optic Disc
  2. Thinning/Degeneration of Chorioretinal Tissue OUTSIDE the OPTIC DISC.
  3. a. B-ZONE: CENTRAL (borders disc): Visible Sclera, Large Choroidal Vessels, RPE atrophy and LARGE SCOTOMA (15-20 % correlation w/Glaucoma)
    b. A-ZONE:: PERIPHERAL: Irregular pigmentation, thinning of chorioretinal tissue and Relative Scotoma (seen in ALMOST ALL NORMAL EYES!!)
19
Q

Optic Nerve: 5 Rs

  1. Myopic Crescent
  2. B-Zone
A
  1. Only ILM and Underlying RNFL Cover the SCLERA

2. BRUCH’s MEMBRANE and Choroid are interposed b/w the remnants of the Retina and SCLERA

20
Q

Optic Nerve: 5 Rs: Retinal and Disc Hemorrhages

  1. Disc (Drance) Hemorrhages: Found where
    a. Superficial
    b. Deep
    c. Most often seen where?
  2. These tend to be associated with defects in what?
    a. Usually in what Glaucoma type patients?
    b. Stage of disease?
    c. How long do they last?
A
  1. On OPTIC DISC or PPA w/in 1 disc Diameter of the Optic Nerve
    a. RNFL: Flame Shaped (Splinter Hemorrhage)
    b. Lamina Cribrosa: More circumscribed and Round
    c. Inferior Pole of Optic NERVE
    * HIGH SPECIFICITY! but LOW SENSITIVITY
  2. RNFL, Neuroretinal Rim Notches, VF Loss
    a. Normotensive Glaucoma
    b. Early-middle stages, decline w/advanced damage
    c. Intermittent: 6 wks to resolve
    * These are a sign of GLAUCOMA PROGRESSION

Ocular Disease II (15 decks)

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