Glaucoma Flashcards
Define Glaucoma?
Optic neuropathy with typical field defect usually associated with ocular hypertension (intra-ocular pressure > 21 mm Hg)
What are the primary causes of Glaucoma?
Acute closed-angle Glaucoma (ACAG)
Chronic closed-angle glaucoma
Primary open-angle Glaucoma (POAG)
What are the secondary causes of Glaucoma?
Trauma
Uveitis
Steroids
Rubeosis iridis (right) - formation of new blood vessels on the surface of the iris
What is the congenital cause of Glaucoma?
Buphthalmos (enlargement of the eye balls)
What is the pathophysiology of Glaucoma?
Ocular hypertension leads to compression and stretching of the retinal nerve fibres
This leads to scotomas (partial loss of vision) and visual field defects
Ocular Hypertension is due to reduced outflow of aqueous humour
What is the reduced outflow of aqueous humour caused by in ACAG?
Obstruction to the outflow (caused by narrowing of the iridocorneal angle, and, hence, narrowing of the canal of Schleem leadign to a rapid and severe rise in IOP
What is the reduced outflow of aqueous humour due to in POAG?
Resistance to the outflow through the trabecular meshwork
What is the epidemiology of Glaucoma?
Prevalence:
- 1% in over 40 yrs
- 10% in over 80 yrs
3rd most common cause of blindness worldwide
What are the presenting symptoms in ACAG?
Painful red eye
Vomiting
Impaired vision
Haloes seen around lights
What are the presenting symptoms of POAG?
Usually ASYMPTOMATIC
Peripheral visual field loss
What are the congenital symptoms of Glaucoma?
Buphthalmos
Watering
Cloudy cornea
What are the signs of ACAG on physical examination?
Red eye Hazy cornea Loss of red reflex Fixed and dilated pupil Eye is tender and hard on palpation Copper optic disc Visual field defect Moderated raised intra-ocular pressure
What are the signs of POAG on physical examination?
Optic disc may be cupped
Usually NO signs
What investigations do you do for Glaucoma?
Goldmann Applanation Tonometry Pachymetry Fundoscopy Gonioscopy Perimetry (Visual Field Testing)
What is Goldmann Applanation Tonometry?
Standard method of measuring intra-ocular pressure
Normal IOP = 15 mm Hg
