Trabecular network has increased resistance so drainage is slower.

Causes/Factors

  • Increasing age
  • Family history
  • Black ethnic origin
  • Myopia (nearsightedness)

Clinical Features

Glaucoma affects the peripheral vision first, resulting in a gradual onset of peripheral vision loss (tunnel vision). It can also cause:

  • Fluctuating pain
  • Headaches
  • Blurred vision 
  • Halos around lights, particularly at night

Investigations

Both apply pressure to cornea and measure response/resistance

  • Non-contact tonometry (less accurate)

  • Goldmann applanation tonometry (gold standard)

  • Slit lamp assessment for increased cup-disk ratio (eye anatomy)

  • Visual field assessment for peripheral vision loss

  • Gonioscopy to assess angle between iris and cornea

Management

Treatment started at an intraocular pressure of 24mmHg or above

Medications:

  • Prostaglandin analgue eye drops (latanoprost) first line - increase uveoscleral outflow
  • Beta-blockers (timolol) reduce the production of aqueous humour
  • Carbonic anhyrase inhibitors (dorzolamide) reduce the production…
  • Sympathomimetics (brimonidine) does both

Surgical: 360 selective laser trabeculoplasty

  • Laser directed at the trabecular meshwork, improving drainage
  • A second procedure may be needed at a later date

Complications/red Flags

  • Irreversible loss of vision (partial or complete) is the main complication of untreated glaucoma.
  • However angle closure glaucoma is considerably more likely than open angle glaucoma to cause blindness