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Glaucoma
Dr. Abdullah Al-Amri
Ophthalmology Consultant
Contents
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Anatomy and basic physiology.
Definition of glaucoma.
Classification of glaucoma.
Gonioscopy.
Measurement of IOP.
Primary open angle Vs closed angle glaucoma.
Management of glaucoma.
Secondary glaucomas.
Anatomy
Basic physiology
• Aqueous is produced by secretion and
ultrafiltration from the ciliary processes into
the posterior chamber.
• It then passes through the pupil into the
anterior chamber to leave the eye
predominantly via the trabecular meshwork,
Schlemm’s canal and the episcleral veins
(the conventional pathway).
• A small proportion of the aqueous (4%) drains
across the ciliary body into the suprachoroidal space and into the venous
circulation across the sclera
(uveoscleral pathway).
• The intraocular pressure level depends on the
balance between production and removal of
aqueous humour.
Definition of glaucoma
• The term glaucoma refers to a group of
diseases that have in common a characteristic
optic neuropathy with associated visual
function loss.
• Although elevated intraocular pressure (IOP) is
one of the primary risk factors, its presence or
absence does not have a role in the definition
of the disease.
• Three factors determine the lOP:
1. The rate of aqueous humor production by
the ciliary body.
2. Resistance to aqueous outflow across the
trabecular meshwork-Schlemm's canal
system.
3. The level of episcleral venous pressure.
Classification of glaucoma
Presentation
Ocular
association
Angle
Course
Acquired
Primary
Open
Acute
Congenital
Secondary
Closed
Chronic
Gonioscopy
Measurement of IOP
• Applanation
tonometry is the
method used most
widely.
• Measurement of lOP
in a clinical setting
requires a force that
indents or flattens
the eye.
• The normal pressure
is 15.5 mmHg.
• The limits are
defined as 2
standard deviations
above and below the
mean
(11–21 mmHg).
Optic nerve cupping
• Cupping is a normal
feature of the optic disc.
• The disc is assessed by
estimating the vertical
ratio of the cup to the
disc as a whole (the cup
to disc ratio).
• In the normal eye the
cup disc ratio is usually
no greater than 0.4.
The visual field
Primary open angle glaucoma
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Affects 1 in 200 subjects over the age of 40.
Affecting males and females equally.
There may be a family history.
The prevalence among blacks is 3 to 4 times
higher than whites.
• Symptomless unless the patient becomes
aware of a severe visual deficit.
Primary angle closure glaucoma
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Affects 1 in 1000 subjects over 40 years.
Females more commonly affected than males.
Strong family history.
Prevalence is more common among Asians
and Eskimos.
• Patients are likely to be hyperopic.
• In acute cases, patient may have sever pain,
photophobia, vision loss and nausea.
• On examination
visual acuity is
reduced, the
eye is red, the
cornea is
cloudy and the
pupil is oval,
fixed and
dilated.
Management of glaucoma
1. Medical treatment.
2. Laser treatment.
3. Surgical treatment.
Medical treatment
Yag laser peripheral iridotomy
(Yag PI)
Surgical treatment
• Drainage surgery (trabeculectomy) relies on
the creation of a fistula between the anterior
chamber and the subconjunctival space.
• The operation is usually effective in
substantially reducing intraocular pressure.
• It is performed increasingly early in the
treatment of glaucoma.
Trabeculectomy
Secondary glaucoma
Open angle:
Closed angle:
• Blood (hyphema), following
blunt trauma.
• Inflammatory cells (uveitis).
• Pigment from the iris.
• Deposition of material
produced by the epithelium of
the lens, iris and ciliary body in
the trabecular meshwork
(pseudoexfoliative glaucoma).
• Steroid-induced glaucoma.
• Raised episcleral venous
pressure.
• Abnormal iris blood vessels
may obstruct the angle and
cause the iris to adhere to the
peripheral cornea, closing the
angle (rubeosis iridis).
• A large choroidal melanoma
may push the iris forward.
• A cataract may pushing the iris
forward (phacomorphic).
• Uveitis may cause the iris to
adhere to the trabecular
meshwork.
Hyphema
Rubeosis iridis
(Neovasular glaucoma)
Phacomorphic glaucoma
Questions