DR.K.SUDHAMATHICONSULTANTEYEQ SUPERSPECIALITY HOSPITALS VISION

Magnitude Second major cause of blindness

Often asymptomatic in early stage.

Damage is irreversible.

Effective treatment is available

DEFINITIONIt is a heterogenous group of diseases in which damage to the optic nerve(optic neuropathy) is usually caused by raised ocular pressure IOP: Depends on the balance between production and removal of aqueous humour

Aqueous Humor DynamicsProduced by non-pigmented epithelia of pars plicataSecretionUltrafiltrationDiffusionAqueous production rate - 2L/minFacility of outflow 0.22L/min/mm of Hg

Aqueous outflowAnatomya - Uveal meshworkb - Corneoscleral meshworkc - Schwalbe lined - Schlemm canale - Collector channelsf - Longitudinal muscle ofciliary bodyg - Scleral spur c - Iris outflowa - Conventional outflow-90%b - Uveoscleral outflowPhysiology

Goldmann Equation

Po = (F/C) + Pv

SymbolMeaningNormal ValueMeasured byPoIntraocular pressureMean = 16 mm HgRange = 10-21 mm HgTonometryFRate of aqueous productionMean = 2l/minRange = 1.8-4.3l/min FluorophotometryCFacility of outflow0.22-0.28l/min/mm HgTonographyPvEpiscleral venous pressure8-12 mm HgVarious devices

NORMAL IOP

Mean= 15.9mmHg 2 SDIOP > 21.7 is abnormal.Factor affect IOP*Age *Sex *Race *Heredity*Diurnal & Seasonal variation*Blood pressure *Obesity *Drugs*Posture *Exercise *Neural *Hormone*Refractive error *Eye movement *Eyelid closure*Inflammation *Surgery

Date Author TitleINTERNAL*

STEPWISE DIAGNOSIS

IOP with Applanation tonometry with Corneal Pachymetry

Good S/L exam/. & Stereoscopic Dialated Ophtalmoscopic examination*AFTER AC DEPTH

Gonioscopy

Formal visual-field testing(WWP)

Imaging

TonometersGoldmannContact applanationPerkinsPortable contact applanationPulsair 2000 (Keeler)Air-puffSchiotzPortable non-contact applanationNon-contact indentationContact indentationTono-Penportable contact applanation

VON HERRICKS ANGLE GRADING-

SIMPLIFIED VAN HERRICKS

Primary GlaucomaIs the iris:Covering the Trabecular meshworkNOT covering the Trabecular meshworkOPEN angle glaucomaCLOSED angle glaucoma

Indentation gonioscopy in iridocorneal contact Part of angle is forced openDuring indentation Part of angle remains closed by PAS Complete angle closureBefore indentationApex of corneal wedge not visible

Optic Nerve HeadOptic Disc 1.5 mm dia1.2 million axons/1000 fasciclesNormal loss 5000 axons/yearOptic NerveSurface nerve fibre layerPrelaminarLaminarRetrolaminar

Anatomy of retinal nerve fibresHorizontalraphePapillomacularbundle

Normal Slit Defect

Wedge defect Total atrophy

Theories of damageMechanical theoryCompression of axons leads to axonal deathVascular theoryIschemia causes axonal necrosisDirect damage due to Pr.Capillary OcclusionInterference to Axoplasmic flow

Glaucomatous DamageAxonal necrosis leading to cuppingLoss of supporting glial tissueNormally leads to disc pallor Histology of Normal and Glaucomatous Optic nerve

Glaucomatous Damage

Types of physiological excavationSmall dimple central cupLarger and deeperpunched-out central cupCup with sloping temporal wall

Pallor and cupping Cupping and pallor correspondPallor - maximal area of colour contrast Cupping is greater than pallorCupping - bending of small blood vessels crossing disc

GLAUCOMAOptic nerve signs of glaucoma progression Increasing C:D ratio Development of disk pallor Disc hemorrhage (60% will show progression of VF damage) Vessel displacement Increased visibility of lamina cribosa

STRUCTURE /FUNCTION EVALUATIONDate Author Title*

*CLASSIFICATIONACORDING TO AETIOLOGY*Primary*SecondaryACCORDING TO APPERANCE OF THE ANGLE*Open angle glaucoma.*Closed angle glaucoma.*Combined mechanism glaucoma*Congenital-present at birth. Infantile, present in first year of life. Juvenile, present in late childhood.

GLAUCOMA CLASSIFICATION*PRIMARY VERSUS SECONDRY*PRIMARYNo detectable ocular or systemic abnormality.Often bilateral.Often familial*SECONDARYPredisposing ocular or systemic abnormality.Often unilateral.Often sporadic

Primary OPEN angle glaucomaIt is the most common type of glaucomaIt is the 2nd cause of blindness in the IndiaIt is also called chronic open angle glaucoma.It causes SLOW damage to the optic nerve, causing gradual loss of vision.

Primary OPEN angle glaucomaPathogenesis:Resistance of drainage of aqueous through the Trabecular meshwok, due to:Thickening of Trabecular lamellae (reduces pore size).Reduction in number of lining Trabecular cells.Increased extracellular material in the Trabecular meshwork spaces.

Signs & symptomsSilent thief of sightFrequent change of presbyopic glasses

Open Angle GlaucomaRisk FactorsAgeRaceFamily HistoryDiabetesMyopiaHypertensionSmoking

Low-tension GlaucomaIOP

SECONDARY OPEN ANGLE GLAUCOMADate Author Title*PreTrabecular-Membrane on T.M.*Epithelial*Endothelial*Fibrous*Fibrovascular*InflamatoryTRABECULAR-Particle obstruct T.M.*RBC-Haem*WBC-Imflammation*NEOPLASTIC CELLS*PIGMENTS*PXF MATERIAL*VISCOUS MATERIAL-SILICONE OIL*HEALON*LENS PARTICLE*VITREOUS*FIBRINTrauma, Toxicity toTM Edema Tears Toxins LaserPosttrabecular-Increased Episcleral VPSUPERIOR VENA CAVA OBSTRUCTIONTHYROID EYE DISEASEA/V FISTULASTURGE WEBER SYNDROME

Pigmentary GlaucomaYoung, white, male myopesPigment dispersion due to zonular contact with irisKrukenberg spindleRadial transillumination defectsTrabecular meshwork pigmentation

Pseudoexfoliation GlaucomaElderly white women Fibrillar material deposited on trabecular meshworkMoth-eaten iris transillumination defectsPigment on trabecular meshwork

STEROID INDUCED GLAUCOMARisk FactorsPOAGDiabetesMyopiaStronger the steroid more the elevation

Primary Angle ClosureGlaucomas*PRIMARY ANGLE-CLOSUREGLAUCOMAANATOMIC FEATURES: SMALL CORNEAL DIAMETER SHALLOW ANTERIOR CHAMBER THICKER LENS SMALL RADIUS OF THE ANTERIOR LENS CURVATURE ANTERIOR LENS POSITION SHORT AXIAL LENGTH HYPEROPIC EYESPRIMARY ANGLE-CLOSUREGLAUCOMAA. INTERMITENT ANGLE-CLOSURE GLAUCOMAB. SUBACUTE ANGLE-CLOSURE GLAUCOMAC. ACUTE ANGLE-CLOSURE GLAUCOMAD. CHRONIC ANGLE-CLOSURE GLAUCOMAE. ABSOLUTE GLAUCOMA

Classification of primary angle closure (PAC)

(1) Primary angle closure suspectAn eye in which appositional contact between the peripheral iris and posterior trabecular meshwork is considered possible (2) Primary angle closure (PAC)An eye with an occludable drainage angle and features indicating that trabecular obstruction by the peripheral iris has occurred, such as peripheral anterior synechiae, elevated intraocular pressure, iris whorling (distortion of the radially orientated iris fibres), glaucomfleken lens opacities, or excessive pigment deposition on the trabecular surface. The optic disc does not have glaucomatous damage.(3) Primary angle closure glaucoma (PACG)PAC together with evidence of glaucoma,

Primary Angle Closure GlaucomaRisk factorsElderlyHypermetropicEmotionally unstable women

GlaucomfleckenIris Atrophy

Primary Angle Closure Glaucoma-Acute congestive attack-EMERGENCY!!!SymptomsSudden painLoss of visionColoured halos

SignsHigh IOPShallow AcOedematous corneaPupil mid-dilated & fixed

Narrow Angle GlaucomaTreatment: Peripheral Iridotomy

Secondary Angle ClosureAnterior iris pulling mechanismNVGICE syndromes------------Posterior pushing mechanismPlateau irisMalignant glaucoma

. Without pupil block - peripheral anterior synechiaeWith pupil block - seclusio pupillae and iris bomb1-Progressive iris atrophy2-Chandler syndrome3-Cogan-reese syndrome

Plateau Iris SyndromeYounger patients, uncommonAc appears to be normal but gonioscopy demonstrates relatively flat irisPlateau iris syndrome high IOP despite LIPlateau iris configuration normal IOP after LI Laser Iridoplasty to shrink peripheral iris

Neovascular GalucomaCausesDiabetesCRVOCarotid vascular diseaseCRAOEales DiseaseSickle cell anemiaCoats disease

Signs & symptomsRubeosis iridisEctropion uveaeNV of angle

Malignant GlaucomaAqueous misdirected posteriorly behind vitreousVitreous moves forward, collapses iris & lens into ACTypically after intraocular surgery particularly cataract & glaucoma

Lens related Glaucoma Intumescence Dislocation and Subluxation Phacolytic Lens particle

Primary Congenital GlaucomaFrom birth till 3 years of ageAutosomal recessivePhotophobiaBlephrospasmEpiphoraHazy corneaHaabs StriaeDeep AC

MANAGEMENT OF CONGENITAL GLAUCOMA*GONIOTOMY TRABECULOTOMY

Medical Treatment of GLAUCOMA Beta-blockers Carbonic anhydrase inhibitors Prostaglandin analogues Miotics Alpha-2 agonists

Surgical treatment of GLAUCOMA Argon laser trabeculoplasty Trabeculectomy/Filtering Sx Cyclocryotherapy Cyclolaser ablation Iridotomy

Thank you

****The permanent surgical cure for narrow angle glaucoma.*Mechanisms of drug action vary and many people require multiple medications.*Creating a path for the aqueous to escape into the sub-conjunctival space is the aim of filtration surgery.