This document discusses normal tension glaucoma, also known as low tension glaucoma. It is characterized by typical glaucomatous optic disc changes and visual field defects, with intraocular pressure consistently below 21mmHg. While the cause is unknown, it is believed to be due to chronic low vascular perfusion that makes the optic nerve more susceptible to damage from normal intraocular pressures. Treatment options include medical treatments to lower intraocular pressure by 30%, trabeculectomy surgery when there is progressive field loss despite pressures in the lower teens, and systemic calcium channel blockers for patients with confirmed peripheral vasospasm.
2. Normal tension glaucoma /
low tension glaucoma
Typical glaucomatous disk changes
and visual field defects
Intraocular pressure constantly below
21mmHg
The angle of the anterior chamber is
open on gonioscopy
No secondary cause for glaucomatous
disk changes
3. Chronic low vascular perfusion makes
optic nerve susceptible for normal IOP
This view is supported by
- Raynaud phenomenon
- Migraine
- Nocturnal systemic hypotension and
overtreated hypertension
- Reduced blood flow velocity in
Ophthalmic A.
4. IOP : consistently lower than 21mmHg
Optic disc changes : Are similar to POAG
with following special features
- Thinning of neuroretinal rim
- Flame shaped
haemorrhages of the
optic nerve rim
(Drance haemorrhage)
- Deep, focal notching
of the rim
- Peripapillary atrophy
5. Visual Field Defects : Similar to POAG but
more deeper,steeper,more localised and
closure to fixation point
7. 1. Medical Treatment to lower IOP
“Aim is to lower IOP by 30% i.e. to about 12-
14mmHg”
Betaxolol is DOC because it also
increases optic nerve blood flow
Drugs with neuroprotective effect like
Brimonidine may be preferred
PG analogues e.g. latanoprost have
greater ocular hypotensive effect in eyes
with normal IOP
8. 2.Trabeculectomy:
When there is progressive field loss
occurs despite IOP in lower teens
3.Systemic calcium channel blockers :
(e.g.nifedipine) in patients with confirmed
peripheral vasospasm