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Glaucoma > Clinical Evaluation of Glaucoma > Flashcards

Clinical Evaluation of Glaucoma Flashcards

1
Q

What specific symptoms should you ask about when taking the history of a glaucoma patient?

A
  • Pain
  • Redness
  • Colored halos around lights
  • altered/loss of vision
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2
Q

What glaucoma-associated condition are hyperopic eyes at risk for? Myopic eyes?

A

Hyperopic eyes are at risk for angle closure

Myopic eyes at risk for Pigment dispersion syndrome

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3
Q

What are s/sx of Tuberous Sclerosis ( Bourneville Syndrome)? What aspects of this disease may lead to glaucoma?

A

P/w ash leaf spots (hypo pigmented cutaneous legions) and adenoma sebaceum (red-brown papular rash on face and chin)

Glaucoma may occur 2/2 vitreous hemorrhage, anterior segment NV, or RDs

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4
Q

What is the hallmark symptom of Neurofibromatosis Type 1? What symptom is strongly associated with glaucoma?

A

Subcuntaneous plexiform neuromas are hallmarks

If located in eyelid, produce an “S-shaped” upper eyelid deformity, which is strongly associated with anterior segment abnormalities and glaucoma

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5
Q

What is the hallmark symptom of Juvenile Xanthogranuloma? What kind of glaucoma can it cause?

A

yellow/orange papules occur on skin of head/neck

may cause secondary glaucoma

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6
Q

What is the hallmark finding of oculocutaneous melanocytosis? What is another name for it? What conditions does it predispose to?

A

aka Nevus of Ota

Hallmark finding is hyper pigmentation of periocular skin

Associated with increased risk of intraocular pigmentation and secondary glaucoma, as well as melanoma

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7
Q

What is Axenfeld-Rieger Syndrome? What is its inheritance pattern? How is it related to glaucoma?

A

AD Inheritence

associated with microdontia, hypodontia, or adontia; anteriorly displaced schwalbes line

50% of patients in late childhood/adulthood develop glaucoma

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8
Q

What are the symptoms of developmental glaucoma?

A

Enlargement of the cornea and breaks in descemets membrane (Haab striae)

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9
Q

What is the hallmark finding in Pigment Dispersion Syndrome (PDS)

A

Krukenberg Spindle= vertical column of pigment located on lens/cornea

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10
Q

What is the hallmark finding in Pseudoexfoliation syndrome?

A

Sampoalesi Line= line of pigment anterior to schwalbes line

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11
Q

What is the hallmark sign of Uveitic Glaucoma?

A

Keratic precipitates

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12
Q

What is the hallmark finding in posterior polymorphous dystrophy?

A

Irregular and vesicular lesions

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13
Q

What is the classic finding in Iridocorneal Endothelial Syndrome (ICE)?

A

cornea with a “beaten bronze” appearance

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14
Q

What is a classic finding in Axenfeld-Rieger syndrome?

A

anterior displacement of schwalbes lines

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15
Q

Why is a goniolens required to view the angle of the eye?

A

Goniolens is required, b/c under nl conditions, light reflected from angle structures undergoes total internal reflection at the tear-air interface

This occurs b/c the critical angle (around 46 degrees) is achieved, and the light is totally reflected back into the corneal stroma

The goniolens eliminates the tear-air interface, and therefore allows visualization of the angle structures

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16
Q

What is dynamic gonioscopy?

A

during gonioscopy, gentle pressure is placed on the cornea using the lens, forced aqueous humor into the angle

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17
Q

When angle closure is present, what image do you see via goniolens?

A

The TM is no longer visible due to the peripheral iris obstructing the TM

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18
Q

What does the Shaffer system for describing an angle measure?

A

The angle b/w TM and Iris

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19
Q

What parameters does the Spaeth grading system take into account?

A

Contour of the peripheral Iris, angle b/w the iris and cornea, and location of iris insertion

Also takes into account effect of dynamic gonioscopy

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20
Q

When does blood enter schlemms canal?

A

In situations where episcleral venous pressure (EVP) is greater than IOP

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21
Q

What do angle vessels look like in neovascular glaucoma?

A

Vessels appear “trunk-like”, cross the CB and scleral spur, and arborize over the TM

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22
Q

What part of the angle is usually most pigmented?

A

The inferior portion, due to gravity

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23
Q

What is the difference between angle pigmentation in PDS compared to Pseudoexfoliation syndrome?

A

In PDS, there is uniform pigmentation of angle

In pseudoexfoliation syndrome, there is patchy pigmentation of the angle as well as sampoalesi lines (line of pigment anterior to schwalbes line)

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24
Q

What are the criteria for angle recession?

A
  • abnormally wide CB band
  • increased prominence of scleral spur
  • torn iris processes
  • marked variation of CB band
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25
Q

What is cyclodialysis?

A

separation of the CB from the scleral spur

Gonio-> deep angle recess with gap b/w CB and scleral spur

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26
Q

How many retinal ganglion cells/axons make up the optic nerve?

A

1.2-1.5 x 10^ 6 retinal ganglion cells

Cell bodies located in retinal ganglion cell layer (below nerve fiber layer)

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27
Q

What is the average diameter of the optic nerve head (ONH)? After leaving the orbit, what happens to the diameter?

A

1.5-1.7 mm in diameter

After exiting the lamina cribosa, the ON expands to 3-4 mm in diameter (difference being the myelination that forms retrolaminarly)

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28
Q

What are the three major cell types found in the retinal ganglion cell layer?

A 
Magnocellular  Neurons (M Cells)
Parvocellular Neurons (P Cells)
Koniocellular Neurons (Bistratified Cells)
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29
Q

What are the M Cells? What are some of their characteristics?

A

Have the largest axonal diameter
Synapse in the magnocellular layer of the LGN
Sensitive to luminance changes (scotopic changes)
Have the largest dendritic field
Primarily processes info related to movement

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30
Q

What are the P Cells? What are some of their characteristics?

A

Account for 80% of RGC layer
Concentrated in the central retina
Smaller axons and smaller receptive fields
slower conductive velocity
Synapse in parvocellular layer of LGN
Discriminate fine detail (high resolution vision)

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31
Q

What are the bistratified cells?

A

Neurons that process information regarding blue-yellow color discrimination

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32
Q

What percentage of the RGC layer do M and bistratified cells comprise?

A

10%

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33
Q

Fibers in which areas of the optic disc are most susceptible to glaucomatous damage?

A

Nerve fibers in the superior and inferior parts of the OD are most susceptible to glaucomatous injury

34
Q

Where is the pre laminar area of the optic nerve located?

A

It is located adjacent to the peripapillary choroid

35
Q

Where is the laminar region of the ON located?

A

It is continuous with the sclera, and consists of the lamina cribosa

36
Q

What is the lamina cribosa?

A

structure consisting of the laminar ON, made up of fenestrated CT through which the fascicles of the ON pass prior to passing through the scleral coat and becoming myelinated

37
Q

Where is the retrolaminar area of the ON?

A

The part of the ON posterior to the laminar cribosa, marking the beginning of axonal myelination and surrounded by the leptomeninges of the CNS

38
Q

What is the lamina cribosa made of?

A

composed primarily of collagen

39
Q

What is transmitted through the lamina cribosa?

A

The fascicles of the optic nerve

CRA/CRV via large central fenestrations

40
Q

In which areas of the lamina cribosa are the fenestrations the largest?

A

Superior and inferior fenestrations are larger compared to the nasal and temporal fenestrations

41
Q

What is the Ring of Elschnig?

A

a rim of CT b/w the optic nerve and adjacent choroidal and scleral tissue

The CT of the lamina cribosa extends from it

42
Q

What is the arterial supply of the anterior portion of the optic nerve?

A

It is supplied by branches of the ophthalmic artery via 1-5 posterior ciliary arteries

Short PCA’s penetrate the perineural sclera to supply the peripapillary choroid as well as most of the Ant. Optic Nerve

43
Q

What is the circle of Zinn-Haller?

A

it is the non-continuous arterial circle located within the perineural sclera

44
Q

Where does the central retinal artery pierce the optic nerve?

A

It pierces the ON 10-15 mm behind the globe

45
Q

What is the blood supply of the superficial nerve fiber layer?

A

Supplied by recurrent retinal arterials originating from the central retinal artery

aka, “epi-papillary” arteries

46
Q

What is the blood supply of the pre-laminar region of the optic nerve?

A

supplied by direct branches of the short PCAs and branches of the circle of Zinn-Haller

47
Q

What is the blood supply of Laminar region of the optic nerve?

A

Branches of the short PCAs or branches of the circle of Zinn-Haller; also, Pial arteries

48
Q

What is the blood supply of the retrolaminar area of the optic nerve?

A

branches of the short PCAs and Pial arterial branches

49
Q

Where do the Pial arterioles originate from?

A

they originate from the Central Retinal Artery before it pierces the retrobulbar optic nerve and branches from the short PCAs

50
Q

Describe the venous drainage of the optic nerve?

A

All areas drain via the central retinal vein

51
Q

What is the earliest physical sign of early glaucomatous cupping?

A

loss of axons/blood vessels/glial cells most pronounced at the superior/inferior poles of the OD starting at the level of the lamina cribosa

associated with compaction of the laminar plate

structural changes may precede visual loss

52
Q

How is glaucomatous cupping in children/infants different from that of adults?

A

Glaucomatous cupping in infants is accompanied by expansion of the entire scleral ring

This may explain why cupping occurs earlier than in adults, and why reversibility of cupping is more prominent with successful treatment

53
Q

What is the definition of glaucomatous optic neuropathy?

A

progressive degeneration of RGCs and their axons, extending from ON to the major visual centers of the brain (i.e. LGN)

54
Q

What is the relationship between the diopter lens used and the size of the ON using both a slit lamp and indirect ophthalmoscopy?

A

60 D Lens: height of SL beam = disc diameter
78 D Lens: height of SL beam x 1.1 = disc diameter
90 D: multiply SL height x 1.3 = disc diameter

55
Q

What is the normal diameter of the OD?

A

1.5-2.2 mm in diameter

56
Q

What are signs of early glaucomatous optic neuropathy?

A 
generalized enlargement of cup
focal rim thinning
superficial disc hemorrhages
nerve fiber loss
asymmetry of cupping b/w eyes
Beta zone peripapillary atrophy
vascular changes (bayonetting, nasalization, etc)
57
Q

What area of the neuroretinal rim is the thickest?

A

The inferior portion of the neuroretinal rim is the thickest.

Thickest: Inferior>Superior>Nasal>Temporal
Mnemonic: “ISNT”

58
Q

Patients with what type of glaucoma are more likely to have disc hemorrhages?

A

Normal tension glaucoma (NTG)

59
Q

What type of illumination allows for best visualization of the nerve fiber axons?

A

Red free illumination

60
Q

What is alpha zone peripapillary atrophy?

A

appears as the typical temporal crescent often seen in patients with myopia with areas of hyper/hypopigmentation

61
Q

What is Beta Zone peripapillary atrophy?

A

represents the loss of the choriocapillaris and RPE, causing a characteristic white appearance adjacent to the disc margin

location usually correlates with position of VF deficits

62
Q

Aside from glaucoma, what are other causes of ON change and vf loss?

A
  • Coloboma

- Drusen

63
Q

What is the difference b/w time domain and spectral domain OCT? How does OCT work?

A

TD-OCT has an axial resolution of 10 uM
SD-OCT has an axial resolution of 3-5 uM

OCT uses interferometry and low coherence light to obtain a high resolution cross section of biological structures

64
Q

What is perimetry?

A

perimetry measures differential light sensitivity, or, the ability of the subject to distinguish a stimulus from a uniform background

“Island of vision in a sea of Darkness”- Traquair

65
Q

What are the functions of perimetry?

A

1- identification and quantification of abnl fields

2- longitudinal assessment to detect glaucomatous progression

66
Q

What does threshhold mean in terms of clinical perimetry?

A

it is the differential light sensitivity at which a stimulus of a given size and duration of presentation is seen 50% of the time

67
Q

What is an isopter?

A

a line of VF representation connecting points with the same threshhold

68
Q

How long does it take for temporal summation to occur? Why is this significant for perimetry?

A

Temporal summation occurs at or greater than 0.5 s

Therefore, most perimeters have a stimulus duration of 0.2s

69
Q

What does SITA stand for? What is it?

A

stands for Swedish Interactive Thresholding Algorithm, employs a logical “best guess” or forecasting approach to threshold estimation

70
Q

What are the two most common programs for glaucoma testing? What programs should be used for patients wtih advanced field loss that threatens fixaton?

A

24 and 30 degree fields, which test the central field using a 6 degree grid

For patients with advanced vF loss that threatens fixation, use 10-2 or C-8 programs

71
Q

In a normal eye, how does the superior VF compare to the inferior VF?

A

In healthy eyes, superior field usually 1-2 dB depressed compared to the inferior field

72
Q

What does the mean difference represent? Pattern standard deviation?

A

Mean Difference= avg sensitivity loss
PSD= highlights localized loss (if increased, suggestive of focal damage)
PSD has greater diagnostic value than mean difference

73
Q

What is SWAP perimertry?

A

= Short Wavelength Automated Perimetry, aka “Blue-Yellow Perimetry”
sensitive in the identification of early glaucomatous damage (due to testing a small population of cells, bistratified cells)

74
Q

What is frequency doubling technology perimetry used for?

A

It is used to measure the contrast detection thresholds, and therefore, is able to test the M neurons

75
Q

What does a cloverleaf pattern on vF indicate?

A

it indicates that the patient stopped paying attention during the test, of that malingering is occuring

76
Q

What are parameters of unreliable VF testing?

A

false positives> 20%

False negatives >33%

77
Q

What two areas of vision are usually retained until the end of glaucomatous VF loss?

A

Central vision and the inferotemporal VF

78
Q

What are typical patterns of VF loss in glaucoma?

A
  • generalized depression
  • paracentral scotoma
  • Arcuate/Bjerrum scotoma
  • Nasal Step
  • Altitudinal Defect
  • Temporal Wedge
79
Q

What is a paracentral scotoma?

A

an island of relative or absolute VF loss located within 10 degrees of fixation

80
Q

What is an arcuate/bjerrum scotoma?

A

occurs in the area of 10-20 degrees from fixation, in its full form, arches from blind spot to nasal raphe

81
Q

What is a nasal step?

A

a relative depression of one horizontal hemifield compared to the other

82
Q

What is an altitudinal defect?

A

near complete loss of superior VF, characteristic of moderate-advanced glaucomatous optic neuropathy

Glaucoma (8 decks)

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