Good Hope Eye Clinic

Angle closure glaucoma..professionals

David Kinshuck, partly from a tutorial given by Prof P Shah

 

Slit lamp technique in glaucoma

glaucoma slit lamp examination technique

Chronic narrow angle glaucoma ..how to examine

By using the same examination technique each time, you are less likely to forget what to look for. An idea (Prof Peter Shah)

  1. start
  2. look for stromal atrophy
  3. glaucomaflecken/central depth
  4. corneal oedema
  5. Van Herrick test (diagram)
  6. convex iris configuration

The normal lens/axial length ratio =15%. Such eyes rarely develop acute glaucoma or need laser PIs. If the lens/axial length ratio >20%, and gonioscopy shows narrow angles, there may be a risk and such a patient may need laser. An axial length measurement (A scan) will give these figures.

 

  normal ACG
corneal diameter 11.6 10.9
anterior corneal curve 7.67 7.61
anterior chamber depth (ACD) 2.8 1.8
lens thickness 4.5 5.1
anterior lens curve 10.3 8.0
axial length 23.1 22.0
ratio / lens thickness / axial length <20% >20%

Gonioscopy appearance

Schwalbe's line

Use the view below to identify Schwalbe's line.

gonioscopy view of angle

Grading gonioscopy appearance ..does the patient need a PI

Angle becomes narrower over the years in some people

  1. anda...anatomically narrow drainage angle
    (ANDA: can see pigmented trabecular meshwork all round, safe)
  2. 2 years later progresses in 33%
    ITC: iridotrabecular contact: cannot see pigmented angle in places
  3. 2 years later progresses in 33%
    PAS...peripheral anterior synechiae
  4. 2 years later...
    PAC: primary angle closure= ITC + IOP (high pressure) + PAS + symptoms

Management

Documenting gonioscopy appearance

Abbreviations, for example (in the direction of the mirror..12 o'clock on the drawing is 12 o'clock in the patient's eye)

  1. ITC: iridotrabecular contact
  2. llNP  ....see non-pigmented trabecular meshwork only
  3. llP  ....see pigmented trabecular meshwork
  4. PAS

drawing gonioscopic appearance

drawing gonisocopy appearance

 

Management principles

narrow angles deomonstrated by ultrasound; they may gradually close

Other slit lamp signs

Ultrasound studies

 

How to laser PIs (Peripheral iridotomy)

Position of PI

position PI between 11 and 1 o'clock, peripheral iris, otherwise problems develop

position PI between 11 and 1 o'clock, peripheral iris, otherwise problems develop

 

 

 

 

 

 

 

Acute attack and PIs

PIs if there is advanced glaucoma

Uveitis present/expected

Observations during laser

Notes related to iridectomy and angle closure

Immediately after laser

 

How to laser a thick iris: pre-treat dark irides

Usually Yag laser above works. Occasionally the iris is so thick surgery is needed (very unusual in the UK). However, some irisis are very thick, but can be lasered by carrying out argon laser first.

argon laser a ring around the pi brfore the yag laser a ring or argon laser (red) is carried out before the Yag (white)

 

Glare after PIs

If patient does get too much glare in the weeks/months after the laser

 

Topiramate and other drugs

This is a new treatment for severe epilepsy and migraine. Unfortunately it may cause angle closure glaucoma, see. Treatment is DIFFERENT FROM  ordinary ACUTE GLAUCOMA .

Uveal Effusion in Asian Eyes

Uveal effusion was found in 11 of 70 eyes with PACG (Kumar 2008)

 

Genes

See   90% in Chinese families

 

Risk factors

See Casson 2009

 

Symptoms of angle closure glaucoma

 

Iridoplasty and plateau iris

trabeculoplasty laser for plateau iris glaucoma

laser for iridoplasty for platueau iris

Plateau iris

This is becoming increasingly noticeable as anterior segment imaging (OCT or ultrasound) becomes available. A plateau iris may cause angle obstruction (and rise in pressure), particularly in ther dark. This is a diagam of the OCT appearance.

diagram of plateau iris

Cataract

Treatment of attack of acute glaucoma 

Immediate 

Diamox

Aqueous misdirection

Manage