• Introduction
• Parts of the eye involved �
• The optic nerve
• How does glaucoma develop?
• Genes
• Optic nerve circulation animation
• Use your mouse..parts of the eye, aqueous flow
• Blood flow in glaucoma
• Genes and your relations
• The sight
• Glaucoma tests
• Treatment, drops, laser, trabeculectomy surgery
• Will the sight get worse?
• Tests each visit
• OCT scans
• Your general health
• Phasing...a word document for patients
• glaucoma website for patients
• Leaflet Cyclodiode
• Leaflet Pigmentary Glaucoma
• Leaflet POAG chronic open angle glaucoma
• Leaflet Trabeculectomy
• optic disc drusen
• high myopia and glaucoma page

• 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)

Glaucoma is usually caused by too much fluid pressing on the nerve at the back of the eye. There are many types of glaucoma, but on this page glaucoma is the term given to the 'chronic open angle' or 'primary open angle' or 'chronic simple' glaucoma.

Pseudoexfoliation and pigmentary glaucomas are both chronic open angle glaucomas, and this page applies.

Glaucoma is not a single disease, but represents conditions that occur for different reasons with the final event being optic nerve damage and visual field loss (Caprioli).

• chronic open angle
  (this page)
• narrow angle
• secondary
• rubeotic
• congenital
• angle dysgenesis

The optic nerve is the 'electric wire' of the eye, an it takes messages about what you see on towards the brain. In the main type of glaucoma the optic nerve is pressed on by extra fluid in the eye, and this may damage the sight in the eye.

See photos

In the common type of glaucoma this drainage system can block. The fluid gets trapped in the eye, and the pressure inside the eye goes up like a tyre being blown up to much.
This pressure or fluid then presses on the nerve at the back of the eye. If the pressure is high or continues for a long time, usually years, the nerve at the back of the eye may become damaged, and eventually the sight may be affected.

The pressure reduces the blood flow in the tiny blood vessels in the optic nerve.

Intraocular presure is strongly related to the metabolic syndrome (Nature 2010) "Metabolic syndrome and other insulin resistance-related features, including hepatic steatosis, increased left ventricular mass, and proteinuria, are strongly associated with IOP".

Normally fluid is made in the ciliary body and circulates to the front chamber, where it drains through the trabecular meshwork out of the eye. enlarge

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Genes control the blockage of the drain (the 'trabecular meshwork'). The relations of patients with glaucoma should all be checked for the condition. If you have glaucoma and you are 70y, then all the relations (mainly children and sisters and brothers) should be checked from the age of 50y. If you have glaucoma age 30y, then even the children related to you should be checked (again: sons/daughters/brothers/sisters). See.

There are 3 particular genes (open angle glaucoma), as decribed Eye 2011.

Myocillin group.

These influence the drainage of aqueous humour through the trabecular meshwork. For instance, and abnormal protein may be produced, and this becomes trapped in the trabecular meshwork cells, and is toxic.

Optineurin group

These influence the axons in the optic nerve in low tension glaucoma. The retinal ganglion cells are weaker than usual and die earlier.

Other genes

There are many other genes: some affect the optic nerve, others affect the trabecular meshwork cells (transport across membranes. Others are related to blood fat levels (toxic to the optic nerve).

Myopia

There be be visual field defects that may be glaucoma related AJO 2011

At first the sight is normal, but it if the glaucoma is severe, the sight may get  progressively worse as opposite.
You cannot 'feel' glaucoma, and usually would would not know there was anything wrong in the early stages.

See Case 1 for students

At first the sight is normal,

then a small area of poor vision may develop.

This can extend, affecting much of of the sight,

or nearly all the sight.

A common type of loss of vision in glaucoma.

1. measuring the eye pressure (for this & other details about your examination
2. looking into the eye at the optic nerve (the nerve can appear 'caved in' which we call 'cupped', as though it has been pressed on.
   See photo, and Case 1 for students
3. testing the field of vision: you sit in a special machine with your head still. Lights flash, and you are asked to press the button if you see the light. If you cannot see the brighter lights, this shows on the computer print out rather like the drawing of the 'castle' above. Here is an online website that enables you to test you own visual field.

Chronic glaucoma is treated with

• eye drops...95% patients

• laser helps a few patients

• some patients need surgery

• The basic treatment for glaucoma is eye drops, and the main drop is Xalatan (or lumigan or travaprost). This is a very effective drop, although does not work in all patients. It causes an allergy in about 1%.
• The second commonest group of drops inhibit the carbonic anhydrase enzyme. This is the chemical that produces the aqueous fluid in the ciliary body. The main drop now is azopt.
• The third is one of the beta-blocker drops such as betaxalol or timolol or teoptic. These drops switch the tap off that makes the fluid. You generally should not use these drops if you get asthma or breathing difficulties, and should use an alternative drop. They may slow the heart down (if they make you dizzy you should stop them) or make your ankles swell.

Drops are described in more detail.

In practice the maximum combination of drops that can be used with few side effects are these 3 drops combined, such as xalatan at night, timolol LA morning, and azopt 2-3 times a day.
There should be a 10 minute gap between drops so one does not wash the other out. This combination does tend to cause slightly sore eyes, which is unfortunately unavoidable (systemic medications cause sore eyes also).

Laser may help a little in older patients, see. Argon laser trabeculoplasty is the main operation available, but selective laser trabeculopasty may be more effective.

However, it is occasionally necessary, especially for younger patients and patients with advanced glaucoma. See some notes here. See animation.

Here are Good Hope mitomycin results. Some wonderful videos and other information here.

Some patients, especially older patients or those who have had previous trabeculectomy, may need cyclodiode laser.

Effectively research has shown that if a pressure is 10mmHg, hardly any eye will be further damaged from pressure, if 11mmHg, then 10% of eyes/patients will notice a deterioration, and so on up to 20mmHg.

It is very hard for an ophthalmologist to tell which eyes will get worse, but

• eyes with healthy looking optic nerves can take a higher pressure

• anaemia, migraine, cold hands, sleep apnoea, suggest a lower pressure is helpful

• if the visual field is full, a higher pressure may be well tolerated

• younger patients with very cupped discs and visual field missing do need very low pressures, ideally 10mmHg

• people with optic disc haemorrhages are at much higher risk

At 20mmHg most eyes will deteriorate. But in practice the risks of treatment, such as having to use lots of drops, and particularly that of diamox tablets or surgery, have to be balanced against the ideal of seeking a pressure of 10 for all patients. In practice accepting a higher pressure in a particular patient may still mean very few patients notice much deterioration, and is the best option. Indeed, in an elderly patient using 2 or 3 drops there may be no safe alternative, especially if this includes xalatan (or lumigan or travaprost).

At each visit these results will be analysed

• eye pressure...measured most visits

• optic nerve appearance and cupping....measured most visits

• visual fields..tested about yearly (see this excellent IGA article which shows you how to interpret your visual field test...it also discusses how often the test should be carried out)
  

New equipment can help make the diagnosis, but such tests are often inconclusive. This scan shows 'suspicious' discs, the patient may have glaucoma ('glaucoma suspect': visual fields were full and pressures normal). Glacuoma is more likely to be present if the comp[uter measures a thinnner nerve fibre layers, as indicated in red (the circles surrounding the optic disc, white arrow, 0.7 cupping right and left).

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