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Glaucoma > Primary Angle Closure Glaucoma > Flashcards

Primary Angle Closure Glaucoma Flashcards

1
Q

What do abnormalities in the structure of the eyes lead to?

A

It can lead to an occlusion of the anterior angle

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2
Q

What does angle closure describe?

A

It describes the process of occulsion of the trab by the iris

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3
Q

What is the major route of drainage for the aqueous?

A

Trabecular mesh work

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4
Q

In angle closure what happens within the anterior chamber?

A

The volume of aqueous increases in the anterior chamber which then causes an increase of iop

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5
Q

Describe acute PACG:

A

Angle closure that occurs quick and sudden and produces a sharp spike in iop causing pain/blur

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6
Q

Describe chronic PACG:

A

Gradual closure which may only have mild sx or no sx at all

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7
Q

Describe the pathophysiology of PACG and the 2 mechanisms which risk PACG:

A

Pupil block: The key mechanism is a blockage of aqueous from p/c through the pupil to the a/c where it’s drained

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8
Q

Describe aqueous production:

A
  • Aqueous is made in epithelial cells in the inner processes of the ciliary body
  • it then flows into the posterior chamber
  • then flows round the anterior lens to pass through the pupil
  • aqueous them reaches the anterior chamber
  • it drains via the trabecular mesh work
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9
Q

Describe what happens to the aqueous with pupil block:

A

The posterior iris becomes attached to the anterior lens which creates a block at the pupil which prevents aqueous flowing from pc to ac for drainage via the trab

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10
Q

Describe the consequences of pupil block:

A

If there’s a pupil block there’s an increase of aqueous in the pc and leads to an increase of pressure.
With the increase of pressure in the pc, the pc pushes on the posterior iris and the iris bows forward. The peripheral iris then contacts the posterior cornea = peripheral anterior synechiae which blocks the angle and prevents drainage

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11
Q

What is the cause of angle closure via pupil block?

A

Px with short axial length or shallow ac are at risk. However dilation drugs can increase the risk of pupil closure. This is because dilation increases the risk of peripheral iris becoming attached to the lens. However with drugs the closure would’ve occurred anyway but the closure isn’t the actual cause of angle closure but accelerates the process

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12
Q

What is the cause of PACG without pupil block?

A

Px’s are vulnerable to angle closure with a thicker iris or if their iris is located more anterior or include a roll in the periphery and these increase the risk of occulsion of angle by iris

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13
Q

Out of POAG and PACG, which is most common?

A

PACG is less common

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14
Q

What is the prevalence of PACG in the U.K. percentage wise?

A

0.4%

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15
Q

How many people suffer with PACG?

A

141,000

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16
Q

What effect does PACG have on age?

A

The risk of PACG increases with age.

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17
Q

What is the risk factor for px’s 70+ of developing PACG?

A

4x

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18
Q

Why are older px’s at risk of angle closure?

A

Due to the growth of the crystalline lens and there’s an increase of thickness and it extends towards the anterior chamber which increases the risk of pupil block

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19
Q

What is the increase of risk of px’s developing PACG with positive family history of PACG?

A

3-4x

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20
Q

Why are px’s with positive family history at risk of getting PACG?

A

Due to similarities in the anatomy of the anterior iris

21
Q

Which ethnicity is more at risk or PACG?

A

Px’s from an Asian heritage so the prevalence is higher in china, Japan, India

22
Q

Which refractive error is more at risk of PACG?

A

Hyperopes

23
Q

What’s the increase of risk of hyperopes getting PACG?

A

3x higher for px’s with 2D of hyperopia

24
Q

Why are hyperopes more at risk of PACG?

A

Due to the shorter axial lengths and shallow anterior chamber which increases the risk of angle closure

25
Q

Which gender is more at risk of PACG and by how much?

A

Females by 3x due to gender differences of the globe

26
Q

What is the referral for PACG?

A

Emergency same day

27
Q

What are the sx for px’s with PACG?

A

Pain, ha, nausea, vomiting, redness (conjunctival/limbal)

28
Q

What is the vision going to be in PACG?

A

Suddenly reduces to 6/60 or poorer

29
Q

What’s a sign of acute PACG?

A

Raised iop which is greater than 40 and may be up to 80

30
Q

How is pupil function in PACG? And how will the appearance of it be? And will it be constricted or dilated?

A

Fixed pupil response and sluggish response to light, appear vertically oval and semi dilated

31
Q

Sometimes examining pupils maybe difficult because may be difficult cause the cornea is cloudy, what causes the cornea to be cloudy?

A

Corneal oedema

32
Q

What does acute angle closure induce?

A

Inflammation

33
Q

As there’s an increase of inflammation with acute angle closure, what does this cause?

A

Cells and flare

34
Q

What occurs in intermittent episodes of angle closure?

A

The anterior chamber becomes occluded but resolves spontaneously which leads to a spike in iop and after ac reopens, the iop returns normal.

35
Q

What can cause intermittent episodes of angle closure?

A

Physiological mydriasis or maybe in a position that causes the lens to shift anterior e.g. Tilting the head forward

36
Q

What is the sx for intermittent angle closure?

A

Blurred vision and haloes round lights

37
Q

What causes haloes round lights in angle closure glaucoma?

A

It’s the oedema of the epithelium

38
Q

What causes oedema in angle closure?

A

It occurs secondary to the pressure on the posterior surface of the cornea by elevated pressure in the anterior chamber and pressure in the posterior cornea disrupts the function of the endo pumps which maintains water levels

39
Q

What sx do px’s with chronic PACG have?

A

None

40
Q

What are the signs of intermittent/chronic angle closure?

A

Optic neuropathy, optic nerve damage, visual field loss

41
Q

In intermittent angle closure when will iop be reduced?

A

When it’s spiked

42
Q

In chronic angle closure, when is iop elevated?

A

It’s just chronically elevated

43
Q

Describe the appearance of glaukomflecken?

A

Grey white spots and fragments on the anterior lens which indicate death is epi cells due to angle closure and raised iop

44
Q

Why is glaukomflecken useful?

A

It indicates whether the eye has experienced angle closure before so it’s more likely in px’s with acute or intermittent issues

45
Q

What is the referral for angle closure glaucoma?

A

Emergency same day and with a telephone

46
Q

What is the referral for intermittent/chronic angle closure?

A

They aren’t emergency same day but they should be urgent within one week referral because there’s high chance of optic nerve damage that may develop rapidly so telephone to know how urgent

47
Q

With acute angle closure glaucoma, what is the treatment?

A

It’s firstly to bring iop under control with medications e.g. Osmotic gradients (glycerol, mannitol), carbonic anhydrase (acetylzolomide), miotic drugs (pilocarpine(, prostaglandin and beta blockers

48
Q

What is the treatment for PACG that isn’t medication? And how does it work?

A

Peripheral idridotomy which creates a hole in the iris for drainage from posterior chamber to anterior chamber of the pupil is blocked and will be done in the other eye too

Glaucoma (7 decks)

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