DIS - Glaucoma Detection Tutorial - Week 3 Flashcards by B H

Does glaucoma commonly lead to blindness?

No, rarely

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Describe the following stages of glaucoma therapy:
Detection
Assessment
Treatment (3)
Monitoring

Detection
-normal vs glaucoma suspect
Assessment
-glaucoma suspect vs glaucoma patient
Treatment
-severity grading
-setting target IOP
-drug selection and surgery referral
Monitoring
-stability vs progression

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Is glaucoma an acquired disease?

Yes with rare exceptions

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Is glaucoma generally symptomatic? Describe (2).

Except for acute angle closure glaucoma, the vast majority of glaucoma is asymptomatic

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Do screenings detect glaucoma? Explain the role of an optometrist.

No, only routine eye exams do
Only optometrists perform routine eye exams

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Can routine eye exams detect glaucoma? Explain the requirement.

Routine eye exams cannot detect glaucoma, only glaucoma suspects
Glaucoma evaluation/assessment is required to diagnose glaucoma

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What is the lifetime risk of glaucoma in first degree relatives of those with glaucoma vs without family history?

22% compared to 2.3% without

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What percentage of glaucoma is thought to be undiagnosed?

50%

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Consider family ocular history. What are two ways to gauge the presence of glaucoma in this component?

Asking patients about their family ocular history
-very unreliable
Examining the 1st degree relatives of existing glaucoma patients
-much more beneficial

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Is diabetes a factor for or against glaucoma? What is the current thought overall?

It is a controversial risk factor
-some studies show greater risk
-some show it is protective against glaucoma
-one showed no association at all
DM is thought to be a mild factor for glaucoma

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Between hypertension and hypotension, which is a risk factor for glaucoma? Explain (3).

Both are:
Higher systolic BP
-drives more blood to the eye
-raises IOP, causing atherosclerosis
Low systolic BP
-reduces blood flow and oxygen to the eye

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What IOP is thought to indicate strong steroid IOP response?

> 10-15mmHg

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What percentage of the normal population has a strong steroid IOP response? What about the glaucoma population?

Normal - 5%
Glaucoma - 95%

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Is IOP steroid response a strong or weak predictor of glaucoma?

Strong predictor

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What two risks associated with glaucoma can antidepressants (note which) and anticholinergic drugs have?

SSRI
Increased risk of narrow angle glaucoma
Mild pipillary dilation and pupil block

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What risk associated with glaucoma can topirimate?

Angle closure due to ciliary body swelling

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Describe the type of glaucoma (or risk factor for glaucoma) the following races are a risk factor for:
Asian
African
Caucasian (2)

Asian - narrow angle glaucoma
African - early onset primary open angle glaucoma
Caucasian - pseudoexfoliation, pigment dispersion

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Describe the type of glaucoma (or risk factor for glaucoma) the following refractive errors are a risk factor for:
Myopia (2)
Hyperopia

Myopia - pigment dispersion, primary open angle glaucoma
Hyperopia - narrow angle glaucoma

Describe the type of glaucoma (or risk factor for glaucoma) the following genders are a risk factor for:
Male (3)
Female (2)

Male - primary open angle glaucoma, ocular hypertension, traumatic glaucoma
Female - normal tension glaucoma, narrow angle glaucoma

Keeping the risk factors posed by certain demographics in mind, do demographics without clinical signs make a glaucoma suspect (2)? Explain with an example.

Demographics without clinical signs do not make a glaucoma suspect
Particular combinations should make you search more carefully
-caucasian, male, myope (pigment dispersion)

True or false
Glaucoma can occur at any IOP

True

Is there a significant IOP overlap between normal and glaucoma populations? Explain.

Yes
Except for IOP >32, both have the same shaped distribution

Compare mean IOP in glaucoma patients who progress compared to those who are stable.

They are almost identical

Can progressive glaucoma occur at normal/low IOP?

Yes

What does elevated IOP detect? Relate to glaucoma suspects. Keeping this in mind, what is the real clinical value of IOP?

Only detects ocular hypertension, not glaucoma The real clinical value of IOP is to advise the practitioner the pressure at which glaucomatous damage occurred and can be used to set target IOP

What is the safe C/D ratio where you can’t have glaucoma? Explain (2).

You can have glaucoma at any C/D ratio, including 0 C/D ratios of 0.8 can be physiologic/healthy

Describe the Five R strategy for assessing the optic nerve. Describe each component.

Ring -disc size, C/D out of proportion to disc size, tilt/rotation Rim -vertical C/D ratio, C/D asymmetry, ISNT rule, notching, pallor Retinal vessels -disc haemorrhages, vessel beyoneting, vessel baring Regions of PPA -beta peripapillary atrophy RNFL -B/D/B pattern, wedge defects

Is the number of retinal ganglion cells tied to globe size? Explain.

All eyes have around 1.5m RGCs, regardless of globe size

What determines disc size?

Scleral foramen

What is the spacing like of axons leaving via a small scleral opening, and how does this affect cupping? What about larger openings? What does this tell us about C/D ratios and optic nerve size?

Axons leaving via a small scleral opening will be more crowded -no ONH cupping Axons leaving via a larger scleral opening have more space -larger ONH cupping Therefore, C/D ratio intrinsically linked to optic nerve size

Does C/D ratio have clinical value without disc size? Explain in terms of disc sizes (30.

Its meaningless -small discs should have almost no cup -regular discs should have regular cups -large discs should have large cups

Are glaucomatous changes easy to detect on small discs (4)?

Difficult to detect -moderate axonal loss occurs without cupping -dramatic axon loss with mild cupping -visual field loss out of proportion to C/D ratio

What tends to happen to patients with large and small discs in terms of glaucoma suspicion?

Large discs with large cups tend to be unnecessarily over-investigated as glaucoma suspects Small discs with small cups tend to be under-investigated

When using slit beam height to match vertical disc diameter using a 90D fundus lens, how should the lens minification effect be taken into account?

x1.3 for 90D

Describe how disc size can be estimated with an ophthalmoscope.

Using the medium aperture, a small disc will fit into the light spot A regular disc will match the light spot A large disc will be larger than the light spot

What anterior chamber angle (VH) should cause suspicion?

<0.3

In what five populations is there increased prevalence of narrow VH angles?

Hyperopia Older age (thicker lens) Asian race Females Anticholinergic drugs

Describe what pseudoexfoliation is, how it forms, and where it deposits.

White fibrillar deposit in anterior eye PXF on lens capsule rubbed off by pupil motion Fibres deposit in trabecular meshwork and impair outflow

What does pseudoexfolation also damage and what is a consequence of this?

PXF also damages lens zonules -lens moves anteriorly -secondary narrow angle glaucoma

What percentage of PXF patients go on to develop PXF glaucoma?

30-50%

What is the most common secondary cause of primary open angle glaucoma?

Pseudoexfolation

What age and gender demographic does pigment dispersion tend to affect? What is the onset?

Predominantly younger male myopes onset age 30-40 years old

What is the anterior chamber like in pigment dispersion syndrome, what happens to the iris, and what is a consequence of this?

Very deep anterior chamber and backward bowing iris Lens zonules rub pigment off posterior iris

Considering that glaucoma is very easy to miss, what is one strategy you could use with every full eye exam?

Assume every patient has glaucoma at each exam At the end of the consult, consciously exclude glaucoma If you cant with certainty, then they are a glaucoma suspect