GLAUCOMA

Glaucoma is a group of disorders characterised by a loss of visual field associated with cupping of the optic disc and
optic nerve damage. Although glaucoma is associated with raised intra-ocular pressure (IOP), it can also occur when
this pressure is within the normal range.

Glaucoma is classified as either open-angle or angle-closure glaucoma. Primary open-angle glaucoma is the most
common.

Risk factors for open-angle glaucoma

  • Older age, black people, family history, genetics
  • Vascular dys-regulation (migraine, vasospasm, abnormalities in ocular blood flow), low ocular perfusion
    pressure, diabetes
  • Ocular factors: Raised intra-ocular pressure, myopia, central corneal thickness – thinner corneas associated
    with increased risk

Clinical features

Open angle glaucoma

  • Mostly asymptomatic
  • History of gradual loss of vision in affected eye or loss of visual field
  • Often suspected after seeing cupping of optic disc on routine fundoscopy or finding elevated intra-ocular
    pressure on screening

Angle-closure glaucoma

  • Sudden onset of severe eye pain and redness, associated with nausea, vomiting and headache
  • Loss of vision in the affected eye
  • Coloured halos or bright rings around lights
  • Hazy-looking cornea
  • Fixed, semi-dilated pupil
  • Shallow anterior chamber
  • Severely elevated IOP. When palpated with a finger, the affected eye feels hard, compared to the other eye
  • If IOP rises more slowly, the patient may be asymptomatic with gradual loss of vision

MANAGEMENT

  • Goal of treatment is to arrest/delay progress of the disease, not for visual improvement. Therapy is usually life long
  • Angle-closure glaucoma is a medical emergency that requires urgent reduction of intra ocular pressure

Refer all suspects to specialist

Open-angle glaucoma

  • Timolol 0.5% eye drops given 1 drop 12 hourly

Angle-closure glaucoma (acute)

  • For urgent reduction of IOP, give mannitol 20% by slow IV infusion until IOP is reduced
  • Reduce intracocular pressure with acetazolamide tablets 500 mg single dose
    followed by 250 mg every 6 hours
  • Plus timolol 0.5% drops 1 drop 12 hourly
Caution
  • Avoid timolol eye drops in patients with asthma, heart block and uncontrolled heart failure