2. GLAUCOMA
Glaucoma is a group of disorders in which
there is damage to the optic nerve due
mainly to the effect of raised intraocular
pressure
3. GLAUCOMA
• Most types of glaucoma can be controlled
but rarely cured
• Poor control of glaucoma leads to blindness
4. Glaucoma
Intraocular pressure depends on the balance
between the production of aqueous and it’s
drainage
Aqueous is produced in the ciliary body
It flows from the posterior chamber through the
pupil into the anterior chamber
Aqueous is removed from the eye via the
trabecular meshwork in the anterior chamber
angle
5. Glaucoma
• Glaucoma is a form of optic neuropathy
• There is damage to the axons of the retinal
ganglion cells at the lamina cribosa or optic
nerve head
• This leads to changes at the optic disc –
cupping and visual field loss
• Optic disc cupping may be asymetrical
6. Visual Fields
• Glaucoma results in loss of visual field, and visual
acuity is only affected in the end-stage of
uncontrolled disease
• Diagnosis and/or progression of glaucoma is typically
assessed using static perimetry, such as the
Humphrey Visual Field Analyser
8. Humphrey visual fields
Glaucomatous field loss
Markedly restricted peripheral fields- tunnel vision-
left eye worse than right
Left eye normal. Right- marked superior
arcuate and lesser inferior arcuate field loss
9. Optic disc cupping
The optic nerve head (ONH), also known as the optic disc, is
made up of a pink neuroretinal rim and of a central pale
optic cup
The neuroretinal rim is made up of nerve fibres derived from
the nerve fibre layer of the retina, whereas the optic cup is
that part of the ONH which does not contain nerve fibres
In glaucoma, there is loss of nerve fibres, and therefore the
optic cup enlarges and the neuroretinal rim becomes
thinner, and this is known as pathological optic nerve
cupping or glaucomatous optic neuropathy
Some people have a large optic cup, but in the presence of a
healthy neuroretinal rim, and this is known as
physiological cupping
10. Look at optic discs with a direct ophthalmoscope
Normal disc on left and cupped disc on right
Note increased area of pallor and the bending of the blood vessels at the disc margin
in the cupped disc.
11. Examination of the glaucoma patient
• Visual acuity
• Visual fields – confrontation testing with
finger counting in four quadrants of each eye,
(not very useful, Humphrey visual fields much
better)
• Pupilary reactions – relative afferent pupilary
defect with marked optic nerve damage
12. Examination of the glaucoma patient
• Examination with light source looking at
anterior chamber depth
• Shine a light across the eye from the lateral
side
normal eye -- both sides of iris illuminated
shallow anterior chamber--
nasal side of iris not illuminated
13. Anterior chamber depth
Normal – note light
illuminating both sides of iris
Shallow – nasal side of iris is
in darkness
14.
15. Measurement of intraocular pressure (IOP)
• Normal IOP is 10-20mm Hg
• It is usually measured with Applanation
tonometry
• Opticians often use puff tonometry
• Digital tonometry (using fingers to gauge
fluctuation) can only tell if pressures are very
high
16. Goldman tonometer
Local anaesthetic plus fluorescein
drops are instilled in the eyes.
The tonometer prism touches the
cornea
The dial is turned until the two green
semi circles just touch.
Intra ocular pressure is then read
measured in mmHg,
Patients must be warned not to rub
their eyes for 15 to 20 minutes after
drops are instilled
17. Primary open angle glaucoma (POAG) risk factors
• Raised intraocular pressure
• Affects 1 in 200 people over 40 years of age,
and 1 in 10 over 80 years of age
• More common and more severe in African
and Caribbean ancestry
• A primary family member with a history of
POAG is associated with increased risk of the
condition
18. Primary open angle glaucoma - symptoms
• It is a “silent” disease, and is therefore often
diagnosed quite late
• Visual acuity may only be lost at the end stage
of the disease whereas visual field has already
gradually been lost throughout the disease
process
• Treatment is aimed at stopping any further
damage to the optic nerve – previous damage
cannot be reversed
19. Primary open angle glaucoma-treatment
Treatment is to lower intraocular pressure
• Medical management by use of one or more anti-glaucoma
medications,
– Topical anti-glaucoma preparations
• Prostaglandin analogues ( increase outflow, of
aqueous)
• Beta-blockers (reduce production of aqueous)
• Alpha2-agonists (enhance outflow of aqueous)
• Carbonic anhydrase inhibitors (reduce production of
aqueous)
• Miotics/Parasympathomimetic agents (enhance
outflow of aqueous)
– Oral anti-glaucoma preparations
• Carbonic anhydrase inhibitors (for short-term use only)
20. Surgical management of POAG
Trabeculectomy
Reserved for a minority of cases where the
condition progresses in spite of maximal
tolerable topical therapy
Selective laser trabeculoplasty SLT
Both above procedures increase outflow of
acquous
25. Acute angle closure glaucoma
Patients with angle closure glaucoma need
urgent referral to an eye unit for treatment
If treatment is not started early permanent loss
of vision can ensue
