GlaucomaGlaucoma

K R Kaini, MDK R Kaini, MD

GlaucomaGlaucoma

DefinitionDefinition TerminologiesTerminologies Glaucoma suspectGlaucoma suspect Ocular hypertensionOcular hypertension Congenital glaucomaCongenital glaucoma PACGPACG POAGPOAG Secondary glaucomaSecondary glaucoma Low tension glaucomaLow tension glaucoma TonographyTonography

Magnitude Magnitude Second major cause of blindness

Often asymptomatic in early stage.

Damage is irreversible.

Effective treatment is available

Country Study Prevalence ofglaucoma

Nepal BhaktapurGlaucoma study(BGS) 2007-2010

1.8

India Aravind ComprehensiveEye Survey(ACES)

2.6

Bangladesh 3.1

China

USA

Global prevalence of glaucomaGlobal prevalence of glaucoma

Country Author/Investigator Prevalence Nepal Suman S.Thapa

Bhaktapur Glaucoma Study 1.9

Tanzania Buhrmann 3.1 South Africa Rotchford 2.7 West Indies (Blacks,Barbados)

Leske 7.0

USA Beaver Dam Study

Klein 2.1

Italy Egna-Newmarket

Bonomi 2.0

Australia Melbourne

Wensor 1.7

India Aravind

Dandonna 1.7

Bangladesh Rahman 2.5

GLAUCOMAGLAUCOMA

What is it?What is it?

A disease of progressive optic A disease of progressive optic neuropathy with loss of retinal neuropathy with loss of retinal neurons and the nerve fiber layer, neurons and the nerve fiber layer, resulting in blindness if left resulting in blindness if left untreated.untreated.

GLAUCOMAGLAUCOMA

““Glaucoma describes a group of diseases that kill retinal Glaucoma describes a group of diseases that kill retinal ganglion cells.”ganglion cells.”

““High IOP is the strongest known risk factor for glaucoma High IOP is the strongest known risk factor for glaucoma but it is neither necessary nor sufficient to induce the but it is neither necessary nor sufficient to induce the neuropathy.”neuropathy.”

Libby, RT, et al: Annu Rev Genomics Hum Genet Libby, RT, et al: Annu Rev Genomics Hum Genet 6:6: 15, 2005 15, 2005

GLAUCOMAGLAUCOMA

There is a dose-response relationship There is a dose-response relationship between intraocular pressure and the between intraocular pressure and the risk of damage to the visual field.risk of damage to the visual field.

What causes it?What causes it?

ADVANCED GLAUCOMAADVANCED GLAUCOMAINTERVENTION STUDYINTERVENTION STUDY

GLAUCOMAGLAUCOMA

GLAUCOMAGLAUCOMAHow do we diagnose it?How do we diagnose it?

IOP is not helpful diagnostically until it reaches IOP is not helpful diagnostically until it reaches approximately 40 mm Hg at which level the approximately 40 mm Hg at which level the likelihood of damage is significant.likelihood of damage is significant. Visual fields are also not helpful in the early stagesVisual fields are also not helpful in the early stages of diagnosis because a considerable number of neurons of diagnosis because a considerable number of neurons

must be lost before VF changes can be must be lost before VF changes can be detected.detected. Optic nerve damage in the early stages is difficultOptic nerve damage in the early stages is difficult or impossible to recognize.or impossible to recognize. 50% of people with glaucoma do not know it!50% of people with glaucoma do not know it!

GLAUCOMAGLAUCOMAIntraocular pressure is not the only factor Intraocular pressure is not the only factor

responsible for glaucoma!responsible for glaucoma!

95% of people with elevated IOP will never have 95% of people with elevated IOP will never have the damage associated with glaucoma.the damage associated with glaucoma.

One-third of patients with glaucoma do not haveOne-third of patients with glaucoma do not have elevated IOP.elevated IOP. Most of the ocular findings that occur in people Most of the ocular findings that occur in people with glaucoma also occur in people without with glaucoma also occur in people without

glaucoma.glaucoma.

GlaucomaGlaucoma

Glaucoma Glaucoma

GlaucomaGlaucomaIntraocular pressureIntraocular pressure

Normal IOP:10-20mm Hg with diurnal variationNormal IOP:10-20mm Hg with diurnal variation Maintenance of IOPMaintenance of IOP Balance between aqueous production and its outflowBalance between aqueous production and its outflow aqueous production rate:2-3 microlitre/min aqueous production rate:2-3 microlitre/min aqueous outflow coefficient:0.2microlitre/min/mm Hgaqueous outflow coefficient:0.2microlitre/min/mm Hg● ● Aqueous humor outflow: Conventional (Trabecular): 90%Aqueous humor outflow: Conventional (Trabecular): 90% Unconventional(uveoscleral): 10% Unconventional(uveoscleral): 10% Factors modifying IOPFactors modifying IOP Physiological variationsPhysiological variations Local mechanical factorsLocal mechanical factors Pharmacological factors Pharmacological factors

Angle of anterior chamberAngle of anterior chamberAnatotomy and physiologyAnatotomy and physiology

Angle of the anterior chamberAngle of the anterior chamber

Shaffer grading of angle width

• Ciliary body easily visibleGrade 4 (35-45 )

• At least scleral spur visibleGrade 2 (20 )

Grade 3 (25-35 )

Grade 1 (10 )

• Only trabeculum visible

• Only Schwalbe line and perhaps top of trabeculum visible• High risk of angle closure

• Iridocorneal contact present• Apex of corneal wedge not visible

• Angle closure possible but unlikely

• Use indentation gonioscopy

3 2 1 0 4

Grade 0 (0 )

Indentation gonioscopy in iridocorneal contact

• Part of angle is forced open

During indentation

• Part of angle remains closed by PAS• Complete angle closure

Before indentation

• Apex of corneal wedge not visible

GlaucomaGlaucomaNormal IOPNormal IOP

Glaucoma Glaucoma MMeasurement of intraocular pressureeasurement of intraocular pressure

ManometryManometry Digital tonometryDigital tonometry Instrumental tonometryInstrumental tonometry Contact tonometerContact tonometer Indentation tonometer: Schiotz tonometerIndentation tonometer: Schiotz tonometer Applanation tonometerApplanation tonometer Goldmann tonometerGoldmann tonometer Perkins hand held tonometerPerkins hand held tonometer Noncontact tonometerNoncontact tonometer PneumotonometryPneumotonometry

IOP measurementIOP measurementManometryManometry

Indentation TonometryIndentation TonometrySchiotz tonometerSchiotz tonometer

Applanation tonometerApplanation tonometer

Pascal and TonopenPascal and Tonopen

Tonometers

GoldmannContact applanation

PerkinsPortable contact applanation

Pulsair 2000 (Keeler)Air-puff

Schiotz

Portable non-contact applanationNon-contact indentation

Contact indentation

Tono-PenPortable contact applanation

Optic NerveOptic Nerve

GlaucomaGlaucoma

Physiological cuppingPhysiological cupping Cup: disc ratioCup: disc ratio

Optic nerve head

a - Nerve fibre layerSmall physiological cup

b - Prelaminar layerc - Laminar layer

• Normal vertical cup-disc ratio is 0.3 or less• 2% of population have cup-disc ratio > 0.7• Asymmetry of 0.2 or more is suspicious

Total glaucomatous cupping

Large physiological cup

a

c

b

Pallor and cupping

Cupping and pallor correspond

Pallor - maximal area of colour contrast

Cupping is greater than pallor

Cupping - bending of small blood vessels crossing disc

GLAUCOMAGLAUCOMAGlaucomatous cuppingGlaucomatous cupping

GLAUCOMAGLAUCOMAThe normal visual field: an island of vision The normal visual field: an island of vision in a sea of darkness:in a sea of darkness:

Anatomy of retinal nerve fibres

Horizontalraphe

Papillomacularbundle

GLAUCOMAGLAUCOMAGoldmann perimeterGoldmann perimeter Glaucoma visual fieldsGlaucoma visual fields

THE VISUAL FIELDTHE VISUAL FIELDHumphrey automated perimetry

GLAUCOMAGLAUCOMAVisual fields in glaucomaVisual fields in glaucoma

EarlyEarly

LateLate

Reliability Indices

• Detected by presenting stimuli in blind spot1. Fixation losses

• Stimulus accompanied by a sound• High score suggests a ‘trigger happy’ patient

• Failure to respond to a stimulus 9 dB brighter than previously seen at same location

• High score indicates inattention, or advanced field loss

3. False negatives

2. False positives

Deviations

• Upper numerical display shows difference (dB) between patient’s results and age-matched normals

1. Total

• Lower graphic display shows these differences as grey scale

• Similar to total deviation

2. Pattern

• Adjusted for any generalized depression in overall field

Global Indices

• Deviation of patient’s overall field from normal

1. Mean deviation (elevation or depression)

• p values are < 5%, < 2%, < 1% and < 0.5%• The lower the p value the greater the significance

• Consistency of responses

3. Short-term fluctuation

• 2 dB or less indicates reliable field• > 3 dB indicates either unreliable or damaged field

• Departure of overall shape of patient’s hill of vision from age-matched normals

4. Corrected pattern standard deviation

• Departure of visual field from age-matched normals2. Pattern standard deviation

GlaucomaGlaucomaclassificationclassification

Congenital or developmentalCongenital or developmental Primary congenital glaucoma (PCG) Primary congenital glaucoma (PCG) Secondary congenital glaucomaSecondary congenital glaucoma AcquiredAcquired PrimaryPrimary Open angle glaucomaOpen angle glaucoma Angle closure glaucomaAngle closure glaucoma SecondarySecondary Open angle glaucomaOpen angle glaucoma Angle closure glaucoma Angle closure glaucoma

Primary congenital glaucomaPrimary congenital glaucoma

Aetiopathogenesis Aetiopathogenesis -inherited as autosomal recessive trait-inherited as autosomal recessive trait -boys more affected than girls-boys more affected than girls -usually bilateral-usually bilateral - 40% cases truely congenital- 40% cases truely congenital - 50% cases usually present within first year- 50% cases usually present within first year - pathogenesis: - pathogenesis: Barkan’s membraneBarkan’s membrane abnormal cleavage of anterior chamber angle abnormal cleavage of anterior chamber angle

GlaucomaGlaucomaEmbryological development of angle structuresEmbryological development of angle structures

Primary congenital glaucoma Primary congenital glaucoma

Clinical featuresClinical features SymptomsSymptoms - photophobia- photophobia - blepharospasm- blepharospasm - watering- watering Signs Signs - buphthalmos- buphthalmos - bluish discoloration of sclera- bluish discoloration of sclera - cornea: megalocornea, hazy, Haab’s striae- cornea: megalocornea, hazy, Haab’s striae - anterior chamber: deep- anterior chamber: deep - iris: tremulous, patches of atrophy may be seen- iris: tremulous, patches of atrophy may be seen

Congenital glaucomaCongenital glaucomaClinical featuresClinical features

GlaucomaGlaucomacongenital…congenital…

Clinical features…Clinical features… - Lens: may be flattened, displaced backward, subluxated- Lens: may be flattened, displaced backward, subluxated - Fundus: cupping of the disc present which may be reversible.- Fundus: cupping of the disc present which may be reversible. - Refractive status: myopia may be seen- Refractive status: myopia may be seen - IOP: raised but not acute- IOP: raised but not acute ManagementManagement

● ● EUAEUA - corneal diameter- corneal diameter - gonioscopy with goniolens- gonioscopy with goniolens - funduscopy - funduscopy - tonometry- tonometry

Primary congenital glaucomaPrimary congenital glaucomaInvestigationsInvestigations

Primary congenital glaucomaPrimary congenital glaucomaInvestigationsInvestigations

Primary congenital glaucomaPrimary congenital glaucomaInvestigationsInvestigations

GoniolensesGoldmann

• Single or triple mirror

Zeiss

• Contact surface diameter 12 mm• Coupling substance required

• Four mirror

• Coupling substance not required• Contact surface diameter 9 mm

• Suitable for ALT• Not suitable for indentation gonioscopy• Suitable for indentation gonioscopy

• Not suitable for ALT

Primary congenital glaucomaPrimary congenital glaucomaInvestigationsInvestigations

GlaucomaGlaucomacongenital…congenital…

Treatment Treatment Medical: it has no significant role Medical: it has no significant role SurgicalSurgical - goniotomy- goniotomy - trabeculotomy- trabeculotomy - trabeculectomy- trabeculectomy - trabeculotomy with trabeculectomy- trabeculotomy with trabeculectomy - trab and trab with 5 FU/MMC- trab and trab with 5 FU/MMC

Management of primary congenital glaucoma

Goniotomy TrabeculotomyMeasurement of IOP and corneal diameters

Thank you!Thank you!