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Chronic Glaucoma
- a.k.a. Chronic simple glaucoma
- divide into open-angle and closed angle claucoma
Primary Open Angle Glaucoma
- Can give raised intraocular pressure leading to
- visual field loss
- open filtration angle of normal appearance
- no obvious causative ocular or systemic conditions
- 1/6 patients have ocular pressure within normal range
Epidemiology
- 1/100 over 40 years
- male:female equal
- accounts for 12% of all blindness in UK / USA
- prevalence high in elderly and blacks
- strong association with family history
- myopia
- association with Diabetes
Mellitus
Pathogenesis
- degenerative changes in trabecular meshwork lead to reduction of outflow
of aqueous.
- mechanical damage / chronic ischaemic damage of optic nerve head
- progressive loss of ganglion cell axons, blood vessels and glial cells in
optic nerve head → visual field loss
Clinical Features
- usually asymptomatic until late stage
- visual field loss usually beginning with nasal field
- may notice scotoma close to fixation
- when performing monocular visual task
- progression often asymmetrical
- high intraocular pressure
- eye ache
- headache
- haloes (transient corneal oedema)
Examination
- visual field loss
- early
- paracentral scotoma with nasal step
- paracentral scotoma alone
- nasal step alone
- sector defects in other quadrants
- later
- arcuate pattern
- tunnel vision
- residual temporal island
Fundoscopy
- neuroretinal rim notching
- diffuse concentric enlargement of cup
- splinter-haemorrhage (risk of imminent damage)
- loss of neurons from optic disc and movement of blood vessels to nasal
edge.
Treatment
- topical
- beta-blockers
- pilocarpine
- dorzolamide (topical carbonic anhydrase inhibitor)
- brimonidine (a2-receptor
agonist)
- latanoprost
- permanent darkening of iris over time
- excessive growth of eye lashes
- surgery
- laser trabeculoplasty / trabeculectomy
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