Questions

🍒What is considered normal intraocular pressure?

Aqueous humour fills the anterior and posterior chamber (both at the front of the eye)

• Divided by the iris

Epithelium of the ciliary muscle secretes produces aqueous humour into the posterior chamber

• The ciliary muscle epithelium is stimulated sympathetically on beta-receptors to increase production of aqueous humour
• Posterior chamber → anterior chamber → trebecular network → canal of schlemm

Intraocular pressure is measured using tonometry

Autonomic nervous system influence:

• 🍒The parasympathetic system acts to decrease intraocular pressure
• 🍒The sympathetic system acts to increase intraocular pressure

High intraocular pressure results in optic neuropathy

🍒What is the pattern of vision loss in glaucoma?

Closed angle glaucoma

• Acute

  

  • Clinical features
    • Symptoms
      • Angle for drainage suddenly closes; abrupt onset
      • Painful red eye
        • Pain is described to be at the “back” of the eye
      • Blurred vision with halos
      • Eye is firm (”rock hard”)
    • Symptoms are triggered when the pupil dilates, because dilation of the pupil closes the angle for drainage (e.g. entering a dark room, drug with dilating side effect (scopolamine, Atropine)
    • 🍒In acute angle closure glaucoma, the eyes are firm on palpation
    • 🍒Symptoms of acute angle closure glaucoma are classically aggravated when entering a dark room
  • Management

    • Medical management is trialled while awaiting surgery (surgery is definitive treatment); may stabilise intraocular pressure and reduce side effects; all used together

      • Acetazolamide
      • Mannitol
      • Timolol (Beta blocker)
      • Pilocarpine (Muscuranic antagonists)

    • Can never use epinephrine in closed angle because it dilates pupil → worsens angle

    • 🍒What is the immediate management of acute angle closure glaucoma

• Chronic

  • Portion of the angle is blocked
  • Develops scarring
  • Intraocular pressure not as high
  • Fewer symptoms (pain) → delayed presentation
    • More damage to the optic nerve
  • Diagnosis made when peripheral vision loss occurs

Primary Open Angle Glaucoma

• Chronic → most patients have this form
• Overproduction of fluid or decreased drainage
• No symptoms until loss of vision occurs
• Can be secondary to Uveitis, trauma, chronic steroid usage, prior retinopathy)
• Risk factors
  • Age
  • Family history
  • African-american
• 🍒On fundoscopy, open angle glaucoma appears with cupping of the optic disc
• Management
  • M3 agonists → contracts ciliary muscle → increases drainage
  • Alpha agonists/Beta blockers → block ciliary epithelium from releasing aqueous humour
  • Prostaglandin analogues → vasodilate Cansls of Schlemm → increase outflow
    • Might darken iris
  • Carbonic anhydrase inhibitor → decrease synthesis of aqueous humour
    • Mild diuretic
  • 🍒What is the management of primary open angle glaucoma?

Congenital glaucoma