Glaucoma refers to the optic nerve damage that is caused by a significant rise in intraocular pressure. The raised intraocular pressure is caused by a blockage in aqueous humour trying to escape the eye.

Glaucoma is the second leading cause of blindness in the world, with open-angle glaucoma being the most common type.

Pathophysiology

Open-angle glaucoma is characterised by an anatomically open angle but with an obstructed and slowed drainage system outflow. The mechanism of blockage is unclear. A rise in increased intra-ocular pressure results, characterised by retinal ganglion cell damage, then peripheral vision loss in early disease and central vision loss in late disease.

Risk factors:

• IOP>23mmHg
• age>50years
• Family Hx of glaucoma
  • Those with a positive family history of glaucoma should be screened annually from aged 40 years
• Black ethnicity

Weak R/F - Myopia, Diabetes mellitus, HTN

PC

*Presence of R/F

• Often, rise in IOP is asymptomatic for a long time
• Peripheral vision affected first, gradually closes in and then tunnel vision
• It can present with gradual onset of fluctuating pain, headaches, blurred vision and halos appearing around lights, particularly at night time.

On examination:

• Visual field testing - Peripheral vision loss, scotomas
• Fundoscopy - Cup to disc ratio>0.4, notching of optic nerve cup (diagnostic)