Primary open-angle glaucoma

Question 1

define glaucomas

Answer 1

optic neuropathies assoc w increased intraocular pressure (IOP)

Question 2

define primary open-angle glaucoma

Answer 2

the iris is clear of the meshwork

defined by an open, normal appearing anterior chamber angle and raised intraocular pressure (IOP), with no other underlying disease.

Question 3

how are glaucomas classified

Answer 3

based on whether the peripheral iris is covering the trabecular meshwork

-the trabecular meshwork is important in drainage of aqueous humour from anterior change of the eye

Question 4

basic pathophys of primary open-angle glaucoma

Answer 4

there is a gradual increase in resistance through the trabecular meshwork
-this makes it more difficult for aqueous humour to flow through the meshwork and exit the eye

therefore the pressure slowly builds within the eye and gives a slow and chronic onset of glaucoma

Question 5

risk factors for primary open-angle glaucoma 7

Answer 5

increasing age

genetics- FHx (1st degree relative)

afro-caribbean ethnicity

myopia (near sightedness)

hypertension

DM

corticosteroids

Question 6

features of primary open-angle glaucoma 4

Answer 6

can present insidiously and is often deteced during routine optometry appt

peripheral visual field loss - nasal scotomas (blind spots) progressing to ‘tunnel vision’

decreased visual acuity

optic disc cupping

Question 7

fundoscopy signs of primary open-angle glaucoma 4

Answer 7

optic disc cuping
*-cup-to-disc ratio >0.7 (normal 0.4-0.7)

optic disc pallor

bayonetting of vessels

additional features

Question 8

diagnosis of primary open-angle glaucoma

Answer 8

case findings and provisional diagnosis is done by an optometrist

referral by GP to ophthalmologist

Question 9

Ix for primary open-angle glaucoma

Answer 9

automated perimetry to assess visual fields

slit lamp

assess risk of future visual impairment

Question 10

management of primary open-angle glaucoma 4

Answer 10

aim: reduce intraocular pressure

ALL are eye drops

1st line - prostaglandin analouges
eg latanoprost

other options
-beta blockers -timolol
reduced production of aqueous humour

carbonic anhydrase inhibitors-dorzoalmide
-reduced production of aqueous humour

sympathomimetic- brimonidine
-reduced production of aqueous humour and increase uveoscleral outflow

Question 11

when is treatment for primary open-angle glaucoma started

Answer 11

if intraoccular pressure 24mmHg or more

*-PTx are followed up closely

Question 12

surgery for primary open-angle glaucoma

Answer 12

trabeculectomy if eye drops ineffective

Question 13

describe trabeculectomy

Answer 13

creating new channel from anterior chamber through the sclera to a location under the conjunctiva

causes a bleb under the conjunctiva where the aqueous humour drains and is then reabsorbed into general circulation

Question 14

side effects of prostaglandin analouges (latanoprost) for open angle glaucoma treatment 2

Answer 14

brown pigmentation of the iris

increased eyelash lenght