Glaucoma describes a group of conditions that affect the eyesight in one or both eyes. If left untreated it can cause total blindness, but treatment can prevent further loss of sight.

The condition occurs when the drainage tubes (trabecular meshwork) within the eye become slightly blocked and prevent eye fluid (aqueous humour) from draining properly. When the fluid cannot drain properly, pressure builds up within the eye (intraocular pressure). This can damage the optic nerve, connecting the eye to the brain, and the nerve fibres from the retina (the light-sensitive nerve tissue that lines the back of the eye).

Glaucoma is often described by the ‘angle’ between the iris (coloured part of eye) and the cornea (transparent covering over the front of the eye).

Types of glaucoma

• Chronic open-angle
  • Aqueous fluid can still reach the drainage tubes, but they slowly become blocked.
  • Most common type.
  • Present in 1/50 of over 40s and 1/10 over 70s (white Europeans).
  • More common in black/African or black/Caribbean descendants.
• Primary angle-closure
  • Angle between the iris and cornea reduces so that the fluid is unable to reach the drainage tubes.
• Secondary
  • Following an injury or infection to the eye such as uveitis (inflammation of middle layer of eye).
• Developmental/congenital
  • Rare but serious.
  • Usually present at birth or develops shortly after.

Symptoms: Chronic

• Slow, often un-noticed, degeneration of eyesight.
• Particularly outer borders of vision.

Symptoms: Acute

• intense pain in eye
• redness and tenderness around eye
• headache
• seeing halos around lights
• quickly progressing loss of vision in one or both eyes

Treatment

• early diagnosis is key for a good prognosis
• eye-drops
  • prostaglandin analogue to increase flow of fluid
  • Beta-blockers to reduce intraoccular pressure
  • carbonic anhydrase inhibitors to reduce produce of fluid
  • sympathomimetics to reduce production of fluid and improve flow
• laser treatment to open up trabecular network
• surgery to remove part of trabecular network (trabeculetomy)

For more information, visit http://www.nhs.uk/Conditions/Glaucoma/Pages/Introduction.aspx