Normal Tension Glaucoma Flashcards
What is normal tension glaucoma?
An optic neuropathy characterised by the optic disc, corresponding visual field loss with open anterior chamber angle and normal IOP
What happens with normal tension glaucoma?
- Open AC angle
- absence of any secondary cause of glaucomatous optic neuropathy
- typical optic disc damage with cupping and loss of neuroretinal rim
What is the mechanical glaucoma damage?
IOP causes mechanical deformation of optic nerve head, damaging fibres
What is the vascular glaucoma damage?
compression of blood vessels leads to reduced perfusion and hypoxia of ONH
What is the biochemical glaucoma damage?
Neurotoxic factors released as fibres damaged leading to cascade of further damage
What does reduced ONH perfusion depend on?
BP, IOP, vascular resistance & autoregulatory mechanism
What is vasospasm?
A sudden constriction of blood vessels. Reduces diameter and flow rate
Is migraine a risk factor for NTG?
is was a found a risk factor, however the low-pressure glaucoma treatment study did not find an association.
What are risk factors for NTG?
- ageing
- family history
- myopia
- blood pressure
- abnormal blood flow
- sleep apnoea
- migraine
What are differential dx for NTG?
- BRAO
- Congenital anomalies
- optic nerve trauma
- demyelinating optic neuritis
- inflammation
What is the treatment for NTG?
- prostaglandin analogues
- beta blockers
- carbonic anhydrases
- alpha agonists
