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OD3 - Clinical Optometry Practice > DIS - Open Angle Glaucoma I - Week 3 > Flashcards

DIS - Open Angle Glaucoma I - Week 3 Flashcards

1
Q

What is the prevalence of glaucoma in Australia? What about elsewhere?

A

Australia - 1.7-2.4%

Elsewhere - 2.5%

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2
Q

Is glaucoma race or age dependent?

A

Yes to both

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3
Q

What percentage of all blindness is due to glaucoma?

A

14%

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4
Q

What was the old definition of glaucoma using IOP? Why is this no longer the definition and what is this called now in place of glaucoma?

A

Used to be IOP > 21mmHg, but many cases of glaucoma never have IOP >21 (LTG)
Now is called ocular hypertension (OHT)

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5
Q

Is both an IOP of 21mmHg and CDR >0.5 a risk factor for open angle glaucoma?

A

Yes

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6
Q

Is progression of glaucoma evident at the first visit? What does this mean for diagnosis and what four factors is this based on?

A 
Progression isnt evident at first visit
Open angle glaucoma is often a presumptive diagnosis based on:
-risk factors
-appearance of the RNFL
-appearance of the NNR of the ON
-typical VF loss
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7
Q

What defines the management of glaucoma?

A

The level of risk for glaucoma

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8
Q

What six things are investigated to diagnose glaucoma?

A 
IOP
Angle
Anterior chmaber
RNFL
ONH (NRR)
Visual field
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9
Q

What is the outcome if there is an absence of all signs?

A

The patient is a glaucoma suspect (low-high risk)

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10
Q

Define a diagnostic risk factor vs prognostic.

A

Diagnostic - attributes present in greater frequency in a disease
Prognostic - attributes that predict faster change once the disease is diagnosed

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11
Q

What 5 eye conditions are considered high risk for glaucoma?

A 
Myopia
Retinal vein occlusion
Eye injury
Iris degeneration
Papilloedema
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12
Q

Which gender is at a lower risk of glaucoma?

A

Female

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13
Q

Is diabetes considered a high risk for glaucoma? What about migraines and sleep apnoea?

A

All are low risk

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14
Q

What defines ocular hypertension?

A

In a normal population, IOP gives a bell shaped curve, therefore ocular hypertension is a statistical concept, the cutoff of which is based on this normal distribution

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15
Q

What is the average IOP including standard deviation? What IOP range would 95% of the population fall within?

A

15.6 ± 2.5 mmHg

95% is within 10-21mmHg

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16
Q

Consider individuals with IOP above 21mmHg. Is this normal? What is this called? Explain (3).

A

Most people above 21mmHg are normal
ONH, RNFL and VF are normal
Called ocular hypertension

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17
Q

What percentage of Australians have ocular hypertension?

A

3%

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18
Q

Can open angle glaucoma be IOP independent? Explain (2).

A

Open angle glaucoma can be IOP independent below 18mmHg - low tension glaucoma

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19
Q

Is high IOP a risk factor for glaucoma? Explain.

A

Above 18mmHg prevalence of glaucoma increases, so it is a risk factor

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20
Q

What are IOP spikes a good indicator of?

A

Progression

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21
Q

What is needed in all low tension glaucoma cases and for what purpose?

A

Need diurnal curve in all low tension glaucoma cases to dismiss spikes

22
Q

What thickness cornea is a higher risk for open angle glaucoma?

A

Thin cornea

23
Q

With tonometry, do thicc corneas tend to return higher or lower IOPs?

A

Higher

24
Q

If there are repeated measurements of IOP > 29mmHg, what must be done (2)?

A

Angle evaluated for closure (gonioscopy or OCT - or both)

CCT measured

25
Q

If there are repeated measurements of IOP < 5mmHg, what should be considered (2)?

A

Hypotony

CCT measurement

26
Q

What aspect of high blood pressure can mean it is a risk for glaucoma?

A

Aggressive BP lowering

27
Q

Is steroid use a risk factor for glaucoma?

A

Yes

28
Q

What race is a risk factor for open angle glaucoma?

A

African-American

29
Q

What race is a risk factor for low tension glaucoma?

A

Japanese

30
Q

Above what age is a risk factor for low tension glaucoma?

A

> 65 years old

31
Q

What is essential to diagnose primary angle closure glaucoma?

A

Gonioscopy

32
Q

For an angle to be considered open, on gonioscopy what structure must the angle be open to and over how many degrees? What else (3)?

A

Angle must be open to ATM for over 180°

Angle must be unimpeded - no pigment, blood, congenital malformation

33
Q

What disc features are generally evaluated for glaucoma (4)?

A

Papillary crescents
NNR thickness
Other signs like haemorrhage
CD ratio

34
Q

Compare a cupped disc to a saucer disc in terms of disc size and defect.

A 
Cup = large disc + surface defect - steep profile for the edge
Saucer = small disc + deep defect - shallow profile/tenting
35
Q

Is it more difficult to see the NRR in a cupped or saucer disc?

A

Saucer

36
Q

If surface fibres are affected, what distance in the visual field is defected?

A

Surface fibres = proximal VF defect

37
Q

If deep fibres are affected, what distance in the visual field is defected?

A

Deep fibres = distal VF defect

38
Q

What is the CDR an indirect index of (2)?

A

NNR and RGC number

39
Q

What does the CDR vary with? How does this affect its reliability for neuropathy?

A

Size of the scleral opening
So CDR is confounded by disc size
-it is not a reliable index of neuropathy

40
Q

Does saucerisation alter CDR? Explain.

A

No, but makes the cup edge harder to see

41
Q

What is an abnormal CDR? Include asymmetry.

A

> 0.7

Asymmetry of >0.2

42
Q

In what percentage of people does the ISNT rule follow? What about IST?

A

ISNT - 50%

IST - 87%

43
Q

Is the ISNT rule a reliable for glaucoma diagnosis?

A

Yes

44
Q

Does the NRR show pallow in early open angle glaucoma?

A

Never shows pallor

45
Q

In a normal NRR, what section is paler?

A

T margin

46
Q

What part of the NRR gets wider?

A

Towards the poles

47
Q

Describe how ON size can be estimated with the following thecniques:
Slit lamp
Opthalmoscopy

A

Slit lamp - adjust the slit size to fit the vertical ON
Ophthalmoscopy - compare vertical ON with medium aperture
-small ON <0.75, large ON >1.25

48
Q

What percentage of the population have very large discs and what should be expected of the NRR, CDR, and ISNT rule?

A

Expect thin NNR everywhere

CDR will be large (≥0.7) but will give IST in most cases

49
Q

With what NNR thickness profile (ISNT) should you do VF with macula (2)?

A

If T=S, I

Or if thinner than expected

50
Q

Are small discs usually saucerised or cupped?

A

Saucer

51
Q

What should you look for in small discs (2)?

A

Look for PPA and RNFL (visible due to crowding)

OD3 - Clinical Optometry Practice (114 decks)

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