Differentials
Normal-tension glaucoma
SIGNS / SYMPTOMS
Usually asymptomatic; this is a subset of open-angle glaucoma in which intra-ocular pressure (IOP) is normal.
INVESTIGATIONS
IOP is normal.
Angle-closure glaucoma
SIGNS / SYMPTOMS
May present acutely with a sudden-onset of pain, redness, and pressure elevation; however, many cases are insidious and asymptomatic if the pressure climbs gradually.
Other signs include poorly reactive and mid-dilated pupil, nausea and vomiting, a hazy cornea, and blurred vision
Patients may report intermittent pain on entering a dark room.[13]
Angle-closure glaucoma is more common in hyperopic (far sighted) eyes.
INVESTIGATIONS
Gonioscopy reveals a closed angle.
High myopia
SIGNS / SYMPTOMS
Although the cup-to-disc ratio may be large, no cup-to-disc enlargement is documented.
Intra-ocular pressure is normal.
Visual field defects do not change over time.[13]
INVESTIGATIONS
Testing shows highly myopic refraction.
Ocular hypertension
SIGNS / SYMPTOMS
Characterised by increased intra-ocular pressure in the absence of evidence of damage to the nerve fibre layer.[1]
INVESTIGATIONS
Characterised by a normal visual field test and no enlargement of the cup-to-disc ratio over time.
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