• acute angle closure glaucoma
• Anatomy
• Blockage to aqueous flow
• What is eye pressure?
• Why does the eye pressure go up?
• What is glaucoma?
• What is angle closure glaucoma?
  
  
• What do you notice?
• What is the laser treatment?
• Will you need drops for ever?
• Ultrasound appearance
  
  
• Cataract surgery
  
  
• for professionals
• how to laser PIs
  
  
• Leaflet download
• Animation
  
  
• www.eyemdlink.com
• common in Taiwan
  

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• What is glaucoma?
  • Text
  • Animation of glaucoma
  • Professionals: notes
  • SLT laser
  • high myopia and glaucoma
• Angle closure glaucoma & narrow angle glaucoma / laser iridotomies
  • Animation of laser iridotomy
  • Chronic narrow angle glaucoma
  • Text
  • Professionals: notes
• Internat. Glaucoma Association
• Intraocular hypertension
• Low tension glaucoma
• Pre-perimetric glaucoma
• Visual field testing
• Drops & tablets for glaucoma
• Animations etc
  • Glaucoma
  • Laser iridotomy
  • Trabeculectomy
  • Rubeotic glaucoma
  • Progression model
  • SLT laser
• Rubeotic glaucoma
  • Text
  • Rubeotic glaucoma animation
  • Professionals: notes
• Students: Cases
  • Case 1
  • Case 2
  • Case 3
  • Case 4
  • Case 5
  • Case 6
  • Case 5
  • Case 8
  • Case 9
  • Case 10
  • Case 11
• Pseudoexfoliation..link
• Pigmentary glaucoma ..link
• Trabeculectomy
  • Text
  • Animation
  • Audit
    • 2006 with photos
    • 2008
• More technical
  • Corneal thickness & IOP
  • Hypotony
  • Arcuate scotomas ..glaucoma?
• Glaucoma letters
• Glaucoma photos (professionals)

The eye is partly filled with a watery fluid, called 'aqueous'. The aqueous is made in the middle chamber of the eye. The aqueous flows forward into the front chamber, and leaves the eye in a the eye's drainage system.

From the drainage system, it flows into the blood stream. (This has nothing to do with tears; tears cover the front surface of the eye only.)

The diagram opposite shows how aqueous flows. The middle chamber is known as the 'posterior' chamber, and the front chamber the 'anterior' chamber. Aqueous flows from the posterior to the anterior chamber, then out of the eye

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Anotomy of the eye. Close up on right, fluid flow as below.

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The eye is partly filled with a watery fluid, called 'aqueous'. The aqueous is made in the middle chamber of the eye, secreted by the ciliary body. The aqueous fluid normally flows forward into the front chamber, and leaves the eye in a the eye's drainage system (the trabecular meshwork and hen the canal of schlemm).

From the drain (canal of schlemm), the aqueous flows into the blood stream. (This has nothing to do with tears; tears cover the front surface of the eye only.)

In open angle glaucoma the blockage is in the trabecular meshwork. In narrow angle glaucoma the iris moves forward and blocks the 'angle'.

Here is the normal aqueous flow.

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If the drain of the eye blocks or is blocked, the fluid cannot drain out of the eye.
If the fluid cannot drain out, the pressure in the eye goes up. This is like a tyre being pumped up and going a little 'hard'.
The extra pressure then presses on the nerve at the back of the eye.

The optic nerve is the 'electric wire' of the eye that takes messages about what you see to the brain.

See animation

The pressure presses on the optic nerve at the back of the eye, and as the nerve is damaged the sight becomes reduced.

As nerve becomes damaged, examination may show the damage as 'caved in'. Medically we call it 'cupped'.

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Because the anterior chamber of the eye is smaller than usual, the process may begin with a blockage between iris and lens (opposite: norally there is a gap between the iris and less as above).

As a result there is not enough space for the aqueous fluid to flow to the front chamber of the eye and out of the eye.

Then... the fluid pushes the iris even further forward, trapping more fluid in the eye (blocking the entrance to the drainage system). As the aqueous fluid cannot drain out of the eye, this puts the pressure up and damages the optic nerve.

This is explained better in this animation

This blockage can develop all of a sudden, perhaps one day coming out of the dark into a well lit room, as the pupil reaches a 'mid-dilated' size. This causes 'acute glaucoma'.

The blockage may be more gradual, 'chronic narrow angle glaucoma'.

Alternatively, you may have open angle glaucoma (see) and then this extra blockage may develop...'open angle glaucoma with narrow angles'.

There are many different terms used to describe these conditions.

Ethnicity and acute glaucoma
Similarly some Asian patients (Taiwanese for example) or Inuits, are far more prone to acute of chronic narrow angle glaucoma at a younger age. In such communities screening services need to examine patients to identify patients who need laser iridotomies.

a partial blockage develops here (black) where the iris and lens are in contact

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as the iris gets pushed forward, a secondary blockage develops here (black arrows) at the entry point to the trabecular meshwork and the canal of schlemm (the drainage system).

The iris...when it is pushed forward in this way blocks the entrance to the drain, so pressure goes up.

1. The condition may develop gradually ('chronic'), as with most glaucoma, and there are no symptoms. The condition may be identified by optometry tests or other eye examinations. (Chronic narrow angle glaucoma). Later, there may be headaches or loss of sight, but by then some vision is lost.
2. In some people mild attacks of acute glaucoma may be occurring. There may be episdoes of blurred hazy sight and slight eye pain or headache.

How to laser PIs for professionals

Laser is the main treatment for this condition at the beginning.

An hour before laser
Before the laser you need drops to make your pupil small. These may give you a headache. Tablets keep the eye pressure down for the first day, and these can make you feel a little funny, with pins and needles.

The laser
'Laser' is a type of very bright focused light. You sit at the laser machine, then drops are used to anaesthetise the front of your eye, and a small contact lens is placed on your eye. When the button is pressed you may feel a slight pain lasting a second or less.

The laser hole
The laser makes a tiny hole in the iris of your eye. The hole is invisible to the naked eye. Once the hole is made fluid can flow though to the front chamber and then out of the eye. This hole keeps the eye pressure down.

Week of laser
You need anti-inflammatory drops for 2 weeks (such as dexamethasone), as well as your regular glaucoma drops if you have any.

Month after laser
Many people do not need drops after 4 weeks. Occasionally the laser only goes half way through the iris, and you may need the hole completed a week or two later.

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hole made with laser allows fluid flow out of eye
See animation

Laser completely prevents an 'attack' of acute glaucoma, so this will never be a problem.

However, some people with chronic angle closure glaucoma may still have a slightly high pressure even after laser, and they need drops indefinitely.
People ask why this is so: imagine an overflowing sink. If you remove the plug (with laser), there may still be a blocked drain.

The diagram opposite shows where the remaining blockage may remain (the black rectangle). Technically the blockage is in the trabecular meshwork, which is the drainage system of the eye.
The blue arrow is the site of the laser hole.
If you need drops you will be followed up in the outpatient clinic. If your doctor thinks you are lucky enough not to need drops, always have your eyes checked by your optometrist every year as a precaution.

See animation.

About one third of patients will not need drops after laser. One third will need drops. Of the other third, some may need drops later. Some of the patients needing drops may need treatment for plateau iris, which includes laser iridoplasty or cataract surgery (our page)

Cataract
Thickening of the lens of the eye is part of the cause of angle closure glaucoma. This happens naturally as we get older, but may happen earlier if we develop a cataract.

As cataracts are common as we get older, (and more common in smokers), we are more prone to acute glaucoma as we get older.

Some patients with unusually small eyes may develop it at a younger age.

Cataract surgery
If you have a cataract then cataract surgery will also prevent attacks of angle closure glaucoma.

As cataract surgery is becoming safer ophthalmologists are starting to recommend cataract surgery for patients with narrow angles .

Ethnicity and acute glaucoma
Similarly some Asian patients (Taiwanese for example) or Inuits, have narrower anterior chambers and crowded angles and are far more prone to acute glaucoma at a younger age. In such communities screening services need to examine patients, to pick out patients who need laser iridotomies.

If you are a health professional and want to have a leaflet to give to give to patients, instead of this web page, see 120k Adobe PDF version.

This Publisher is a Microsoft Publisher document, and you are welcome to download it and print copies. You are welcome to make changes for your patients (you can edit the leaflet in Microsoft Publisher).

You will need M Publisher 2000 to open and print the document. M Publisher is bundled as part of Microsoft Office. The only condition is that you let me know if there are any errors.
The document is 150k. The document can be printed out and photocopied to provide a double-sided leaflet 1/3 A4 size for your patients. The address is http://www.diabeticretinopathy.org.uk/leaflets/angleclosureglaucoma.pub