Glaucoma - (also a red eye)

Question 1

What is acute angle closure glaucoma?

Answer 1

In acute angle-closure glaucoma (AACG) there is a rise in IOP secondary to an impairment of aqueous outflow

Question 2

Diagnosis ?

Answer 2

Acute angle closure - ophthalmic emergency need immediate treatment to prevent irreversible glaucomatous damage due to raised intraocular pressure

Question 3

Pathophysiology of acute angle closure?

Answer 3

Aqueous humour produced by the cilliary body in the posterior chamber of the eye.

Diffuses from posterior chamber through the pupil into anterior chamber

From the anterior chamber, fluid is drained into the vascular system via the trabecular meshwork and Schelmm canal contained within the angle

Acute angle closure - peripheral iris blocking outflow of aqueous humour

Question 4

What are Anatomical factors that make acute angle closure more likely?

Answer 4

Plateau iris - anterior location of iris-lens diaphragm
shallow anterior chamber
Floppy iris

Question 5

What are some risk factors for acute angle closure ?

Answer 5

Age average = 60 yrs
F:M = 4:1 (shallower anterior chamber)
1/1000 caucasians, 1/1,000 asians
Hypermetropia (long sighted)
FHX
Medications - amitriptylline, oxybutynin

Question 6

What are the symptoms of acute angle closure?

Answer 6

Severe ocular pain
headache
systemic : nausea and vomiting /abdo pain
decreased vision
coloured haloes around lights
Photophobia
symptoms worse with mydriasis e.g. watching TV in dark

Question 7

What are the signs seen in acute angle closure?

Answer 7

Semi-dilated non reactive pupil
ciliary injection
corneal oedema (hazy dull cornea)
Shallow AC
Flare in AC
raised IOP
tense of palpation

Question 8

Investigations for closed angle glaucoma?

Answer 8

• Goldman applanation tonometry to assess for elevated IOP
• gonioscopy (literally looking, oscopy, at the angle, gonio): a special lens for the slit lamp that allows visualisation of the angle

Question 9

What is the medical treatment for acute angle closure?

Answer 9

AIM= lower the IOP

• pilocarpine - to contract ciliary muscle → open trabecular meshwork → increased outflow of the aqueous humour)
• timolol- decreases aqueous humour production)
• alpha-2 agonist (e.g. apraclonidine, dual mechanism, decreasing aqueous humour production and increasing uveoscleral outflow)
• IV acetazolamide (reduces aqueous secretions)

PASSMED

Question 10

What is the surgical treatment for acute angle closure?

Answer 10

Laser peripheral iridotomy (curative often)
Prophylactic to other eye

creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle

Question 11

How does Laser peripheral iridotomy work?

Answer 11

creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle

Question 12

How do pilocarpine eye drops help in the treatment of acute angle closure?

Answer 12

a direct parasympathomimetic
causes contraction of the ciliary muscle → opening the trabecular meshwork → increased outflow of the aqueous humour

Question 13

How does Iopidine (same as apraclonidine an alpha 2 antaognist on passmed) work in the treatment for acute angle closure?

Answer 13

dual mechanism, decreasing aqueous humour production and increasing uveoscleral outflow

Question 14

Pass med also list a beta-block e.g. timolol for treatment of acute angle closure how does this work?

Answer 14

decreases aqueous humour production

Question 15

How does IV acetazolamide work in treatment for acute angle closure?

Answer 15

reduces aqueous secretions

Question 16

What are glaucomas?

Answer 16

optic neuropathies associated with raised IOP.

classed based on whether the peripheral iris is covering the trabecular meshwork as important in drainage of aqueous humour from the anterior chamber of the eye

Question 17

What is primary open angle glaucoma ?

Answer 17

The iris is clear of the meshwork but the trabecular meshwork functionally offers an increased resistance to aqueous outflow -increased IOP

Question 18

What are risk factors for getting primary open angle glaucoma?

Answer 18

Increasing age
Genetics - 1st degree relative = 16% chance
Afro Caribbean ethnicity
myopia
HTN
Diabettes
corticosteroid use

Question 19

How does primary open angle glaucoma present?

Answer 19

Peripheral visual field loss - nasal scotomas progressing to ‘tunnel vision’

Decreased visual acuity

optic disc cupping

Question 20

What signs do you get on fundoscopy for primary open angle glaucoma?

Answer 20

• Optic disc cupping
  cup:disc ratio >0.7 (0.4-0.7 normal) as optic cup widens and deepens
• Optic disc pallor
  (optic atrophy)
• Bayonetting of vessels (vessels break as disappear into deep cup and re-appear at base)
• Cup notching (inferior where vessels enter disc)
• Disc haemorrhages

Question 21

Who makes the diagnosis of primary open angle glaucoma?

Answer 21

Provisional diagnosis and finding cases is done by optometrist

referral to opthalmologist by GP

final diagnosis is done by extensive investigations

Question 22

What investigations to definitively diagnose primary open angle glaucoma?

Answer 22

• Automated perimetry to assess visual fields
• slit lamp examination with pupil dilation to assess optic nerve and fundus for a baseline
• Goldmann Applanation tonometry - measure IOP
• Central corneal thickness measurement
• Gonioscopy to assess peripheral anterior camber
• assess risk of visual impairment (RF e.g. IOP,
  central corneal thickness (CCT), FHX, life expectancy)

Question 23

How are patients with primary open angle glaucoma managed?

Answer 23

Majority: eye drops to lower IOP to prevent progressive loss of visual field

NICE:
* 360° selective laser trabeculoplasty (SLT) first-line to people with an IOP of ≥ 24 mmHg NICE

• 1st line: prostaglandin analogue (PGA) eye drop = latanoprost
• 2nd line: b-blocker (timolol), carbonic anhydrase inhibitor of sympathomimetic (alpha2 adrenoreceptor agonist) eye drop
• surgery in the form of a trabeculectomy may be considered in refractory cases

Passmed

Question 24

Why is reassessment of pts with primary open angle glaucoma important? When should it be done more frequently ?

Answer 24

to exclude progression of visual field loss

more frequently if:
IOP uncontrolled
high risk pt
progression of visual field loss

Question 25

What is an example of a Prostaglandin analogue, how does it work?

Answer 25

Latanoprost
MOA: Increases uveoscleral outflow

Question 26

What is an example of an sympathomimetic?
How does it work?
Who should avoid it?
Adverse side effects?

Answer 26

-Brimonidine (alpha2 - adrenoreceptor agonist)

• reduces aqueous production / increases outflow
• Avoid if taking MAOI (Parkinsons) or tricyclic antidepressants
• Adverse : hyperaemia

Question 27

What is normal IOP?

Answer 27

10-21mmHg (mean 16)

take into account with Central corneal thickness (CCT)

Question 28

What are the examination findings in chronic open angle glaucoma?

QUESMED CARD

Answer 28

Assessment of visual fields reveals loss of peripheral fields as well as a central scotoma in advanced disease.

Fundoscopy may reveal optic disc cupping, where the cup appears large in relation to the optic disc.