glaucoma what is glaucoma? - locnet · 1 glaucoma bruce james stoke mandeville hospital what is...
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Glaucoma
Bruce James
Stoke Mandeville Hospital
What is Glaucoma?
A group of diseases in which damage to
the optic nerve occurs as a result of
intraocualar pressure being above the
physiological norm for that eye
Glaucoma
“No doubt the excavation of the disc in glaucoma is not a purely mechanical result of exalted pressure; it is, in part at least, an atrophic condition which, though primarily due to pressure, includes vascular changes and impaired nutrition in the substance of the optic disc...which may probably progress even though all excess of pressure be removed”
Priestley Smith 1885Emeritus Professor of OphthalmologyUniversity of Birmingham
Optic Disc Cupping
In glaucoma damage to the axons occurs in the lamina cribrosa of the optic nerve head leading to Retinal Ganglion Cell Death probably by a disruption of axonal transport
Burgoyne
Increased Translaminar pressure Gradient
Mechanical Changes
• Stress on the lamina cribrosa may not necessarily lead to deformation, the scleral canal may expand and tighten the lamina
Physiological Changes
• Interference with the delivery of nutrients to the optic nerve
• Increases energy required for axonal transport
Burgoyne
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Diagnosis of Glaucoma
“Medicine is a
science of
uncertainty and an
art of probability”
William Osler 1849-1919
As appealing as it is to have incontrovertible scientific backing for
our actions in treating our patients, we often
simply don’t know what to do.
Caroline Wellberry
The Lancet 375 May 2010
Symptoms
• Chronic open angle glaucoma-None
• Angle closure glaucoma– Pain
– Redness of eye
– Reduced Vision
Signs Chronic Open Angle Glaucoma
• Reduced Visual Field
• Pressure may be raised
• Increased Optic Disc Cupping
Secondary Examination
» Pachymetry
» Gonioscopy
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How is glaucoma Classified?
• According to the appearance of the angle of
the eye
Open and Closed Angle Glaucoma
Signs
Meaningful
interpretation,
reducing
uncertainty, requires
accurate
measurement
IOP measurement
The Instrument
Calibration
The Eye
Tear film
Corneal Thickness
Corneal Shape
Corneal abnormalities
Accommodation
Eye Position
The Patient
Increased venous pressure
Orbicularis Contraction
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The Technique
Tonometer -Tear Contact
Fluorescein Concentration
Duration of Tonometer
Contact
Pressure on the eye by the
examiners fingers
Sampling Errors
IOP Varies with:-
Pulse
Respiration
Blinking
Exercise
Posture
Time
>3 mmHg in 17% of
consecutive measurements by 2
different ophthalmologists Thorburn W. The accuracy of clinical applanation tonometry.
Acta Ophthalmol 1978;56:1-5
Pressure
FieldComputerised Field Test
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Disc Cupping
Disc Photography Tomography
Looking for change
Retinal Nerve Fibre Layer
Polarimetry
OCT Retinal Nerve Fibre LayerLAyerAchieving a Diagnosis - Synthesis
Matching the field and the disc
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Achieving a diagnosis
» Normal Eye
» Ocular Hypertension
» Glaucoma
» Uncertainty
» Remember the effect of the diagnosis on the
patient. Family History is important.
Treatment
Lowering IOP will slow down
or prevent further damage but
will not undo the damage that
has been done
How can we reduced Intraocular Pressure?
• With eye drops
• With laser
• With surgery
To reduce the production
of aqueous
To increase the removal of
aqueous
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Have amended it comments appreciated
Adapt the therapies available to the individual patient
• Pharmaceutical
• Laser SLT
• Surgical
• Nothing?
Eye Drops include:-
• B-blockers
• Prostaglandin analogues
• Alpha-adrenergic agonists
• Carbonic anhydrase inhibitors
• Parasympathomimetic agents
• Combination therapy
• Preservative free drops
Problems Include
• Failure to achieve the target pressure
• Side Effects (General)
• Respiratory problems
• Cardiovascular
• Side Effects (Local)
• Ocular surface disease
• Allergy
• Intraocular inflammation
• Macular Oedema
Laser
• To the trabecular meshwork (SLT laser)
• To the ciliary body
% reduction in IOP following SLT LaserConventional Surgery
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0
5
10
15
20
25
30
19982002
2007 2010 2013
IOP
mm
Hg
Pre and post operative IOP for each year group
Starting IOP Pre-op IOP iop week 1 iop 1 year iop last fu
Year
Parameter Mean Range
Age 61.75 years 42-77 years
IOP at start 15.5mmHg 14-21mmHg
IOP pre-operation 14.5mmHg 11-21mmHg
CCT 472um 462-566um
IOP 1 week 6.7mmHg 0-28mmHg
IOP one year 7.6mmHg 4-14mmHg
IOP last FU (21-31/12) 8.4mmHg 5-15mmHg
VA Start 6/5-6/9
VA 1 year post op 6/6-6/12
Outcomes of Trabeculectomy for NTG n=11
But potential complications
» Infection
» Pressure too low
» Pressure too high
» Cataract formation
MIGS Surgery (Usually at the time of or
following cataract surgery)
» Stents
» Trabectome
» Endo-Cyclodiode
The Aim of Treatment
• To balance treatment effectiveness and side-
effects
• To preserve vision until death - not caused
by glaucoma treatment
Points to consider
• Age
• Severity
• Life Expectancy
• Cost Effectiveness
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Angle Closure
• Pain
• Redness Reduced Vision
• Cloudy Cornea
• Dilated Pupil
• Very High Pressure
Treatment
• Reduce IOP with intravenous Diamox
• Pilocarpine to constrict pupil
• Peripheral iridotomy
Secondary Glaucoma
• A result of other ocular disease or trauma
Treatment
As with chronic open angle glaucoma
Except:-
Rubeotic glaucoma usually secondary to retinal ischaemia (diabetes, CRVO) anti-VEGF treatment and pan-retinal photocoagulation with yclodiode laser to the ciliary body.
Glaucoma
• Treatment is preventative
• Care with the diagnosis - use all available
evidence but don’t be too seduced by
modern technology!
• Try to do no harm!