glaucoma what is glaucoma? - locnet · 1 glaucoma bruce james stoke mandeville hospital what is...

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1 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 1885 Emeritus Professor of Ophthalmology University 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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Page 1: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

1

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

Page 2: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

2

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

Page 3: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

3

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

Page 4: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

4

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

Page 5: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

5

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

Page 6: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

6

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

Page 7: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

7

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

Page 8: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

8

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

Page 9: Glaucoma What is Glaucoma? - LOCNET · 1 Glaucoma Bruce James Stoke Mandeville Hospital What is Glaucoma? A group of diseases in which damage to the optic nerve occurs as a result

9

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!