1introduction & classification of

8/7/2019 1Introduction & Classification of

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theGlaucomas


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LearningOutcomes

ncomp et ngt smo u eyous ou ;

Understand

the

mechanisms

for

developing

glaucoma

Haveknowledgetointegratewiththeirclinicalpracticalskillstoenabledifferentialdiagnosisofthevarious

Understandaimsoftreatment

ave now e geo treatmentm et o s

Understand

the

implications

of

and

the

possible

need

or rea men reg memo ca on nspec a cases


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A

B


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Glaucomaisthenameappliedtoagroupof

otentiall

blindin

diseasesthat

share

the

commonfeatureofacharacteristicoptic

functionincluding

progressive

visual

field

loss

,


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However,thereareanumberofdisease

rocessesthat

lead

to

the

man ,

varied

sub

typesofglaucoma,whichexplainsthevariety

groupssuch

as

differences

in

symptoms

and


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Glaucomaisaleadingcauseofblindnessroug ou ewor . wases ma e a e

prevalence

of

glaucoma

throughout

the

world

.

About6.7millionaffectedindividualswere

disease.

Chronico enan le laucomaisthe3rd leadin causeofblindnessinthedevelopedworld

Hasrecentl

found

to

be

the

second

most

commonsinglediseasecauseofUKblindnessandpartialsightregistrations,accountingfor8%o a cer ca ons


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Anum ero a ternat vemet o s orc ass cat on

remain

in

use

both

in

clinical

practice

and

the

literature ac sc eme as s raw ac san ene s,an use

ofalternativemethodsbydifferenttextbooksand

Itis

useful

to

have

abroad

awareness

of

all

adifferentschemetotheonethatyouprefer.

Someclassification

schemes

ma

rovide

more

appropriate,descriptiveandclinicallyusefuldiagnosesthanothers.


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IntheUKitisthesecondmostcommonsingle

diseasecause

of

UK

blindness

and

artial

si ht

registrations,accountingfor8%ofall

InIsrael?


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Whyclassify?

Makin

andstatin

an

accurate

dia nosis

is

criticaltothecareofeveryglaucomapatient

managementofeachindividualpatientto

per ormappropriateexaminations

adopt

the

relevant

management

strategy

and

discussappropriateaspectsofthedisease,prognosis,

treatmentandexpectationswitheachindividual


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Thistraditionalschemedividestheglaucomas

intosub

rou s

on

the

basis

of

whether

a

knownexistingdiseasehadacausalrolein

development

There are two main divisions


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A.Primaryglaucoma

Thisgroupscharacteristicisthatithasno

contributionfrom

ocular

or

s stemic

disease

Primaryglaucomas aregenerallybilateraland

.


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.

Thisgrouphasaknowncontributionfrom

ocularor

s stemic

disease.

Secondaryglaucomas maybeunilateralor

Somehavingageneticbasis

Othersareacquired


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Thesegroupsmayagainbesubdivided


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Knowledgeofthevarietyofglaucomas and

howthe

are

rou ed,

or

classified,

is

thereforeinvaluablebackgroundto

diseaseprocesses


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Knowledgeofthevarietyofglaucomas and

howthe

are

rou ed,

or

classified,

is

thereforeinvaluablebackgroundto

diseaseprocesses.


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PrimaryGlaucomas SecondaryGlaucomas

Openangle Openangle

.

ii.primary

open

angle

glaucoma

(highpressuretype)

.

conditions

ii.iatrogenicsecondaryglaucomas

iii. secondar to extraocular

conditions

i.primaryangleclosureglaucoma

acute,intermittentacute,chronic

i.secondaryangleclosure

glaucomawithpupilblock

.

glaucomawith

anterior

pulling

mechanismwithoutpupilblock

iii.secondar an leclosure

glaucomawithposteriorpushing

mechanismwithoutpupilblock

i.primarycongenitalglaucoma

ii.primaryinfantileglaucoma

.

congenital

anomalies

Classificationoftheglaucomas basedonknowncauseforIOPelevation


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(2)Initialpathologicalevent

Thedisadvantageofusingtraditionalcause

basedclassification

is

that

itreflectsourlackofunderstandingofthedisease

itshistorical

dependence

on

elevated

IOP

does

whomIOPisnormal


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Ithasthereforebeensuggestedthatgrouping

accordin

toinitial

events

that

commence

the

processleadingtoglaucomaprovidesamore

theglaucomas

Thefourmajorsubdivisionswithinthis

schemeare:


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. penang eg aucomas w ou o er nownocularorsystemicdisorders;

. ng ec osureg aucomas w ou o er nownocularorsystemicdisorders;

.

D.Glaucomas associatedwithotherocularand

PATHOLOGICALEVENT


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A.Openangleglaucomas withoutotherknown

ocularor

systemic

disorders

i.Chronicopenangleglaucoma(COAG)

.


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B.Angleclosureglaucomas withoutother

i.Pupillaryblockmechanismglaucoma

.


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C.Developmentalglaucomas

i.Congenitalglaucoma

.

iii.AxenfieldRieger syndrome

ivPeters

anomaly

.

vi.Otherdevelopmentalanomalies


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D.Glaucomas associatedwithotherocularand

i.Associatedwithdisordersofthecornealendothelium

. ssoc ate w t sor erso t e r san c ary o y

iii

Associated

with

disorders

of

the

lensiv.Associatedwithdisordersoftheretina

v.Associatedwithintraoculartumours

vi.Associated

with

elevated

episcleral venous

pressure

vii.Associatedwithinflammation

viii.Steroidinducedglaucoma

ix.Associated

with

ocular

trauma

x.Associatedwithhaemorrhage

xi.Followin intraocularsur er


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(3)Mechanismbasedclassification

Thisschemedividesglaucomas onthebasisof

themechanism

underl in

a ueous

outflow

obstructionthatleadstoelevationof

.


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.

T isgroupisc aracterise yanteriorc am e r

angle

structures

being

visible

by

gonioscopy,

and

may esu v e n o

(i)pretrabecular causesofopenangleobstruction,

such

as

membranes;

(ii)clinicallynonvisiblehistopathologic changestowithinthetrabecular meshwork;

iii

osttrabecular obstructions

to

a ueous

outflow,suchaspathologyofSchlemms canalandraisedepisceral venouspressure.


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.

Thisgroupischaracterisedbyanteriorchamber

an lestructures

not

bein

visiable b

gonioscopyduetophysicalobstructionofthe

appositionof

the

peripheral

iris

to

either

the

withinthisgroupare;


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Subdivisionswithinthisgroupare:

irisispulledtowardstheperipheralcornea;

ii

Posterior

pus ing

mec anisms

in

w ic

thepressurebehindtheirispushesittowards

theperipheralcornea.

withoutpupilblock


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.

Thisgroupischaracterisedbynotbeingableto

fallinto

either

of

the

recedin

cate ories.

Cl ifi ti f th l b d h i f tfl b t ti


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Classificationoftheglaucomas basedonmechanismsofoutflowobstruction

Openangle Closed angle Developmental

A.Pre

trabecular (membrane

overgrowth)A.

Anterior

(pulling)

mechanismsA.

High

insertion

of

anterior

uvea

.

(neovascular glaucoma)

ii.endotheliallayer

iii. e ithelial down rowth

.

ii.contractureofinflammatory

precipitates

.

iijuvenileglaucoma

iii.associatedwithother

develo mental anomalies

iv.fibrousingrowth

v.inflammatorymembrane

.

interbeam

spaces)

i.idiopathic

ii.clo in ofmeshwork

.

mechanismsi.withpupilblock

.

trabecular meshworkand

Schlemms canal

iii.alterationsinmeshwork

structure

. .

ii.Petersanomaly

iii.associatedwithother

develo mentalanomalies

C.Posttrabecular

i.occlusionofSchlemms canal

C.Iridocorneal adhesions

i.broadstrands(Axenfeld

.

pressure ii.Finestrandsthatcontract

andcloseangle(Aniridia)


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.

Inadditiontothesethreeschemes,other

commonl

usedclassifications

have

been

basedon

ageatonset(congenital,infantile,juvenileor

adult)


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RRitch,MBShields(1982)TheSecondary

Glaucomas.CV

Mosb ,

St

Louise

JSalmon,JJKanski(2003)Glaucoma.3rd Edition.

,

EuropeanGlaucomaSociety(2003).Terminology

andGuidelinesforGlaucoma(2ndEd).Dogma

Publications Savona Ital . D wnl d r mwww.eugs.org


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DrPaulSpryandInstituteofOptometry

1introduction & classification of

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