Open-Angle Glaucoma: Gradual Vision Loss

Question 1

What is primary open-angle glaucoma?

Answer 1

Increased IOP but with the trabecular meshwork clear of the peripheral iris.

Question 2

How is open-angle glaucoma differentiated from acute-angle closure glaucoma?

Answer 2

Can be classified based on whether the peripheral iris is covering the trabecular meshwork, which is important in the drainage of aqueous humour from the anterior chamber of the eye. In open-angle glaucoma, the iris is clear of the meshwork. The trabecular network functionally offers an increased resistance to aqueous outflow, causing increased IOP.

Question 3

What is the epidemiology of open-angle glaucoma?

Answer 3

Affects 0.5% of people >40
10% aged >80
Males = Females

Question 4

What are risk factors open-angle glaucoma?

Answer 4

Genetics (16% 1st degree)
Black ethnicity
Myopia
Hypertension
Diabetes Mellitus
Corticosteroids

Question 5

How is open-angle glaucoma usually detected?

Answer 5

During routine optometry appointments (Fundoscopy)

Peripheral visual field loss - nasal scotomas progressing to ‘tunnel vision’
Decreased visual acuity
Optic disc cupping

Question 6

What is seen on Fundoscopy in open-angle glaucoma?

Answer 6

Optic disc cupping
Optic disc pallor
Bayonetting of vessels
Cup notching, disc haemorrhages

Question 7

How is open-angle glaucoma diagnosed?

Answer 7

Optometrist detected and referred to opthalmologist via GP.

AUTOMATED PERIMETRY to assess visual fields
SLIT LAMP EXAMINATION with pupil dilatation to assess optic nerve and fundus for a baseline
APPLANATION TONOMETRY to measure IOP
Central corneal thickness measurement
GOINOSCOPY to assess peripheral anterior chamber configuration and depth
Assess risk of future visual impairment

Question 8

What are the symptoms and symptoms of open-angle glaucoma?

Answer 8

Slow risk in intraocular pressure: symptom-less for a long period
Typically present following an ocular pressure measurement during a routine examination

Increased intraocular pressure
Visual field defect
Pathological cupping of the optic disc
Slit-lamp: optic nerve head damage
IOP > 24 mmHg as measured by Goldman-type applanation tonometry

Question 9

How is open-angle glaucoma managed?

Answer 9

Eye drops - aim to lower intra-ocular pressure

Prostaglandin analogue (PGA) eyedrops (LATANOPROST)

Second-line: Beta-blocker (TIMOLOL), carbonic anhydrase inhibitor (DORZOLAMIDE) or sympatomimetic eydraps

Advanced: surgery or laser treatment (TRABECULECTOMY)

Reassessment: to exclude progression and visual field loss