DIS - Glaucoma Treatment and Progression Tutorial - Week 7

Question 1

Is the majority of glaucoma chronic or acute?

Answer 1

Chronic

Question 2

What is the first step of glaucoma treatment?

Answer 2

Grading the severity

Question 3

Describe the MEC glaucoma clinic 5 category classification for glaucoma (GSS). Describe where on the glaucoma continuum each of these fits.

Answer 3

High risk ocular hypertension - acceleration of apoptosis
Pre-perimetric glaucoma - ganglion cell death to RNFL change (detectable)
Early perimetric glaucoma - SWAP and SAP VF changes
Moderate perimetric glaucoma - VF change (moderate)
Severe perimetric glaucoma - VF change (severe) and blindness

Question 4

Define ocular hypertension.

Answer 4

IOP >21mmHg without structural/functional defects

Question 5

Does ocular hypertension always mean an increased risk of glaucoma? Explain.

Answer 5

No, some pose no greater risk than normal, while others have a much likelihood of developing into glaucoma

Question 6

Should all ocular hypertension be treated?

Answer 6

No, only high risk ocular hypertension

Question 7

List 5 factors that will indicate high risk ocular hypertension.

Answer 7

Central corneal thickness <555um
IOP >26mmHg
Age over 60 years
C/D greater than 0.7
Risk of 15% or more by OHTS risk calculator

Question 8

Consider the risk given by the OHTS risk calculator, what is a disadvantage and what categories of risk should be treated vs monitored?

Answer 8

It doesnt consider every risk factor
Monitor low/moderate risk
-treat if multiple additional risk factors present
Treat all high risk

Question 9

Describe what is meant by pre-perimetric glaucoma. Include ocular (3) and imaging signs (2).

Answer 9

No visual field defect, but 3 or more ocular and/or imaging signs of glaucoma
Ocular signs
-rim thinning
-disc haemorrhage
-NFL wedge defect
Imaging signs
-GCC defect
-RNFL defect

Question 10

What stage of glaucoma is the most likely of all to get wrong and why? Why does this error tend to occur?

Answer 10

Pre-perimetric glaucoma due to red disease (false positives)
-up to 25% of all scans
-tends to occur if OCT is used in routine exams

Question 11

Describe what is meant by pre-perimetric glaucoma (2). Include three VF defects typical at this stage and give two indications of severity (MD and VFI).

Answer 11

3 or more ocular/imaging signs
Repeatable VF defect
Typical defects are nasal step, arcuate, and paracentral defects
Severity
-MD 0 to -6dB
-VFI 100 to 80%

Question 12

Describe what is meant by pre-perimetric glaucoma (2). Include a VF defect typical at this stage and give two indications of severity (MD and VFI).

Answer 12

3 or more ocular/imaging signs
Repeatable VF defect
Typically a large defect in one hemifield
Severity
-MD -6 to -12dB
-VFI 80 to 60%

Question 13

Describe what is meant by pre-perimetric glaucoma (2). Include two VF defects typical at this stage and give three indications of severity (MD and VFI).

Answer 13

3 or more ocular/imaging signs
Repeatable VF defect
Typical defects are a large defect in one hemifield and a moderate defect in the other hemifield
Severity
-MD worse than -12dB
-VFI less than 60%
Any VF defect within 5 degrees of fixation

Question 14

Up to what percentage of ganglion cells may be lost before early glaucomatous defects become evident?

Answer 14

40-50%

Question 15

In addition to risk factors, list 5 other factors that influence the decision to treat ocular hypertension to prevent glaucoma.

Answer 15

Patient age
Life expectancy
Medical co-morbidities
Burden of treatment
Patient preference

Question 16

What percentage of untreated ocular hypertension will progress to glaucoma? What does it reduce to if IOP is lowered by 22%?

Answer 16

10%
Lowering the IOP by 22% reduced glaucoma rate to 5%

Question 17

When detecting the conversion from ocular hypertension to glaucoma, was this detected predominantly by structural changes or visual field losses?

Answer 17

Predominantly structural change

Question 18

What percentage of untreated early perimetric glaucoma will remain stable?

Answer 18

38%

Question 19

Keeping in mind the risk of progressing to glaucoma from ocular hypertension (and early perimetric glaucoma getting worse), describe a major factor that influences whether or not treatment should be initiated. Explain why it matters (2).

Answer 19

You may elect to closely monitor or begin treatment
-can wait for structural/functional losses before deciding to treat
Age at the time of diagnosis is very important
-younger patients usually require treatment as they will have the disease for many years
-often dont need to treat the elderly (>80) as they may not live ling enough to lose vision

Question 20

Do moderate and severe perimetric glaucoma always require treatment at any age?

Answer 20

Almost always

Question 21

What must be done if treatment is initiated?

Answer 21

Target IOP must be set

Question 22

What is considered the baseline IOP when setting a target IOP?

Answer 22

Highest recorded IOP prior to treatment

Question 23

List 6 factors that can influence target IOP?

Answer 23

Glaucoma severity grading
Ocular risk factors
Systemic risk factors
Family history
Age
Life expectancy

Question 24

Describe the target IOP for low, medium, and high risk given by the NHMRC guidelines.

Answer 24

Low - 20% decrease or 24mmHg
Moderate - 30% decrease or 17mmHg
High - 14mmHg

Question 25

Describe the target IOP for each stage of the five stages of glaucoma.

Answer 25

High risk OTH - 20% Pre-perimetric - 25% Early perimetric - 30% Moderate perimetric - 40% Severe perimetric - under 14mmHg This varies from practitioner to practitioner

Question 26

If the difference between baseline and target IOP is greater, what is more likely required?

Answer 26

Surgical intervention

Question 27

List 6 treatment options for glaucoma.

Answer 27

Topical eyedrops Oral medications Laser -SLT Cataract surgery and MIGS Incisional surgery -trabeculectomy -tube shunts Ciliary body ablation

Question 28

What percentage of patients can reach target IOP with a single drug? What about with maximal medical therapy?

Answer 28

Single drug - 50% MMT - over 90% -MMT in glaucoma is 4 different classes of drugs

Question 29

List 5 current classes of topical glaucoma drugs, and two emerging drugs.

Answer 29

Current -prostaglandin analogues -beta blockers -carbonic anhydrase inhibitors -alpha agonists -cholinergics New classes -nitric oxide -rho kinase inhibitors

Question 30

Describe the mechanism of action for pilocarpine in reducing IOP. Include dosing and 4 common side effects.

Answer 30

Pupil miosis, mechanically pulling iris away from trabecular meshwork, increasing outflow QID dosing Symptoms include brow-ache, dimmed vision, myopic shift, retinal detachment

Question 31

Describe the mechanism of action for beta blockers in reducing IOP. Include dosing and 5 potential systemic side effects.

Answer 31

Adrenergic, decreases aqueous production in ciliary bodies BID dosing Symptoms include athsma/COPD, impotence, masks hypoglycaemia, bradycardia, postural hypotension/fainting

Question 32

What three drug classes revolutionised glaucoma treatment?

Answer 32

PGAs, alpha agonists, and carbonic anhydrase inhibitors

Question 33

Describe the mechanism of action for PGAs in reducing IOP. Does it alter the trabecular meshwork? What of its systemic side effects? What about ocular side effects (4)?

Answer 33

Increased outflow through uveo-scleral pathway -no alteration to TM No systmeic side effects Ocular side effects include conjunctival erythaema, adnexal darkening, lash lengthening, orbital fat atrophy

Question 34

Describe the mechanism of action for alpha agonists in reducing IOP (2). Include dosing and 3 potential side effects.

Answer 34

Decreased aqueous production Possible neuroprotection via increased ONH perfusion BID/TID dosing Type 4 adnexal allergy Dry mouth Nightmares

Question 35

What can carbonic anhydrase inhibitors be described as, and how does it work? List the dosing and its side effects compared to diamox. Include 2.

Answer 35

Liquid diamox Decreased aqueous production BID/TID dosing Much fewer systemic side effects vs diamox Possible sulphonamide allergy/SJS, stinging

Question 36

Why does IOP rise with age (2)?

Answer 36

Reduced outflow due to icnreased rigidity of trabecular meshwork beams and increased GAG extracellular matrix

Question 37

What is vyzulta a combination of? Explain the mechanism on how it reduces IOP. What is the dosing?

Answer 37

Latanoprost + nitric acid -once daily Nitric oxide is a potent vasodilator and smooth muscle relaxant

Question 38

What is the rationale behind using nitric oxide for IOP reduction? Explain how it affects ocular structures to reduce IOP (3).

Answer 38

NO aqueous levels are lower in glaucoma patients compared to normals NO relaxes trabecular beams, schlemms canal, and episcleral veins

Question 39

Explain the problem with delivering nitric oxide to the eye and how it is done in the case of glaucoma treatment.

Answer 39

Gases cant easily reach the eye -nitric oxide would require a donating moiety -attached to latanoprost, separates within the eye

Question 40

Compared to latanoprost alone, by how much does combination with nitric oxide decrease IOP?

Answer 40

~1.5mmHg

Question 41

What is the estimated reduction in glaucoma progression for every 1mmHg IOP reduction?

Answer 41

10%

Question 42

Describe how rho kinase inhibitors work to reduce IOP (2), include the dosing, and describe efficacy compared to latanoprost.

Answer 42

Decreases outflow resistance in deep regions of the TM near schlemms canal and in episceral veins Also decreases aqueous production Slightly less effective vs latanoprost

Question 43

Can rho kinase inhibitors be combined with PGAs? Explain.

Answer 43

Yesd Synergistic uveoscleral and trabecular outflow

Question 44

What drug class is used in almost all cases as initial therapy?

Answer 44

PGAs

Question 45

List the topical treatment paradigm for glaucoma (6).

Answer 45

Start with PGAs Change to a different PGA Add a beta blocker (usually a combo) Add CAI Add alpha agonist (alphagan or simbrinza) Add cholinergic (pilocarpine)

Question 46

Describe the rule of tenths for glaucoma (2).

Answer 46

Of 100% of those with glaucoma, 10% fail to reach target IOP with maximal medical therapy (4 drug classes) 10% of those may progress to bilateral blindness even with best treatment

Question 47

List three uses of oral diamox in the context of glaucoma. What is chronic use limited due to?

Answer 47

Acute angle closure glaucoma Post-operative cataract surgery IOP spikes Short term use while waiting for glaucoma filtration surgery Chronic use limited due to systemic side effects

Question 48

Describe a use for oral beta blockers in the context of glaucoma.

Answer 48

Lower conversion from OHT to glaucoma in those taking oral beta blockers Useful if unable to manage eyedrops (ie arthritis)

Question 49

Name an actual supplement that can actually decrease IOP. List its ingredients (2) and dosage. What else can it do aside from decreased IOP? What is its onset of action and efficacy vs topical glaucoma therapy? What is a disadvantage? In what three cases is this a good choice?

Answer 49

Mirtogenol -bilberry extract (30%) -french maritime pine bark extract (70%) -one or two capsules daily Reduces IOP, increases ocular blood flow to the ONH Slower onset of action vs topical therapy Less effective alone than in combination with latanoprost Expensive (no PBS) Excellent option for patients with ocular surface disease, optic nerve head drusen, other optic neuropathies

Question 50

What do studies suggest of the efficacy of vitamins A and C for glaucoma (2).

Answer 50

Dietary intake showed a beneficial association with open angle glaucoma Blood levels of vitamins do not show a clear relation

Question 51

What do studies suggest of the efficacy of low and high dose vitamin B3 for glaucoma (2)?

Answer 51

Lower dose had no effect on IOP but was neuroprotective Higher dose lowered IOP and was also neuroprotective -done in a mouse model

Question 52

What is the efficacy of SLT surgery comparable to (topical medication)?

Answer 52

Similar to PGA (25 to 30%)

Question 53

List three advantages and 5 disadvantages of SLT surgery.

Answer 53

Advantages No patient compliance issues Lower drug costs over time Repeatable Disadvantages IOP lowering effect not sustained Patients potentially lost to follow-up Doesnt always work Doesnt work well with NTG May make PGAs less effective

Question 54

From an ophthalmology perspective, what is the suitability of SLT for initial therapy of glaucoma vs topical drops?

Answer 54

SLT more cost effective than drops

Question 55

Describe why cataract surgery decreases IOP and whether or not the effect is sustained.

Answer 55

Less lens volume in posterior chamber Effect sustained for several years

Question 56

List three areas a stent can be placed for glaucoma surgery.

Answer 56

Trabecular Suprachoroidal space Subconjunctival space -recalled due to endophthalmitis

Question 57

Describe incisional therapy.

Answer 57

Creates an opening in the eye to allow aqeuous to leave the globe, into the subconjunctival space

Question 58

What is ciliary body ablation surgery reserved for?

Answer 58

Painful blind eyes with elevated IOP

Question 59

When should a patient be reviewed after treatment is initiated?

Answer 59

4 weeks

Question 60

What should be done if target IOP is reached? Include review schedule (3).

Answer 60

Reinforce the need for ongoing treatment -cessation will cause IOP to rise -review again in a month -again in three months -again every 6 months

Question 61

What are two possible reasons why IOP tagret hasnt been reached?

Answer 61

Drops havent been used -patients are in denial -havent gotten into regular habits yet Drops may actually be ineffective -use the treatment paradigm

Question 62

How long does it usually take patients to form habits with eyedrops?

Answer 62

66 days

Question 63

Is poor compliance easy or hard to detect?

Answer 63

Very hard, patients will lie on purpose

Question 64

What is the average adherence to oral drug, glaucoma drug, and behavioural compliance (diet/exercise) like?

Answer 64

Oral - 75% Glaucoma - 50% Diet/exercise - 10%

Question 65

What must be done once target IOP is reached?

Answer 65

Monitor for deterioration -if stable, continue therapy as is -if deteriorating, IOP must be reduced further

Question 66

When looking for structural changes in glaucoma, should the latest scans be compared to the previous scans, or baseline scans?

Answer 66

Always compare to baseline scans

Question 67

What does event analysis detect?

Answer 67

Detects change has occurred in a part of the visual field

Question 68

What does trend analysis detect?

Answer 68

Detects rate of change of the whole visual system over time

Question 69

Does glaucoma progression tend to occur via structural or functional losses, or both together?

Answer 69

Infrequently together, mostly tends to occur with just either one

Question 70

If progression is confirmed, by how much should IOP be lowered?

Answer 70

A further 10%

Question 71

Can all glaucoma cases be made to stabilise?

Answer 71

Not