OPHTHALMOLOGY Glaucoma MBChB 4 Prof P Roux 2012

WHAT IS GLAUCOMA? A GROUP OF DISEASES IN WHICH INTRAOCULAR PRESSURE (IOP) CAUSES DAMAGE TO VISION. COMMON FEATURES: Optic disc cupping Visual field loss Raised intraocular pressure (Usually)

AQUEOUS HUMOUR DYNAMICS: PRODUCTION OUTFLOW SECRETION ULTRAFILTRATION TRABECULAR MESHWORK (ANGLE) UVEOSCLERAL PATHWAY

Aqueous outflow Anatomy a - Uveal meshwork b - Corneoscleral meshwork c - Schwalbe line d - Schlemm canal e - Collector channels f - Longitudinal muscle of ciliary body g - Scleral spur c - Iris outflow a - Conventional outflow b - Uveoscleral outflow Physiology

OPEN-ANGLE ANGLE-CLOSURE PRIMARY SECONDARY CONGENITAL INFANTILE JUVENILE ADULT CLASSIFICATION: ACCORDING TO: ANGLEASSOCIATED FACTORSAGE OF ONSET

a. Pre-trabecular - membrane over trabeculum Open-angle b. Trabecular - ‘clogging up’ of trabeculum c. With pupil block - seclusio pupillae and iris bombé Angle-closure d. Without pupil block - peripheral anterior synechiae cd a b ANGLE

SECONDARY GLAUCOMAS 1. Pseudoexfoliation glaucoma 3. Neovascular glaucoma 2. Pigmentary glaucoma 4. Inflammatory glaucomas 5. Phacolytic glaucoma 7. Iridocorneal endothelial syndrome 6. Post-traumatic angle recession glaucoma 8. Glaucoma associated with iridoschisis ASSOCIATED FACTORS

PATHOGENESIS INDIRECT ISCHAEMIC THEORY (MICROCIRCULATION/ PERFUSION PRESSURE) DIRECT MECHANICAL THEORY (DAMAGE TO NERVE FIBRES)

Theories of glaucomatous damage Direct damage by pressure Capillary occlusion Interference with axoplasmic flow

Risk Factors 1. Age - most cases present after age 65 years 2. Race - more common, earlier onset and more severe in blacks 3. Inheritance Level of IOP, outflow facility and disc size are inherited Risk is increased by x2 if parent has POAG Risk is increased x4 if sibling has POAG 4. Myopia 5. Diabetes

EXAMINATION 1.TONOMETRY (PRESSURE) 2.GONIOSCOPY (ANGLE) 3.VISUAL FIELD 4.OPTIC DISC (OPTIC NERVE)

Tonometers Goldmann Contact applanation Perkins Portable contact applanation Pulsair 2000 (Keeler) Air-puff Schiotz Portable non-contact applanation Non-contact indentation Contact indentation Tono-Pen Portable contact applanation

Goniolenses Goldmann 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

Indentation gonioscopy Differentiates ‘appositional’ from ‘synechial’ angle closure Press Zeiss lens posteriorly against cornea Aqueous is forced into periphery of anterior chamber

Humphrey perimetry

Anatomy of retinal nerve fibres Horizontal raphe Papillomacular bundle

Optic nerve head a - Nerve fibre layer Small physiological cup b - Prelaminar layer c - 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

Types of physiological excavation Small dimple central cup Larger and deeper punched-out central cup Cup with sloping temporal wall

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

TREATMENT OF GLAUCOMA MEDICAL SURGERYTrabeculectomy LASER 1 2 3

ANTIGLAUCOMA DRUGS 1.ALPHA-2 SELECTIVE ADR. AGONISTS - Alphagan 2.BETA-ADRENERGIC BLOCKING AGENTS - Betagan 3.CARBONIC ANHYDRASE INHIBITORS - Trusopt 4.PROSTAGLANDIN DERIVATIVES - Xalatan 5.PILOCARPINE 6.ADRENALINE

DECREASED AH PRODUCTION ADRENERGIC AGONISTS -ALPHA-2 ADRENERGIC ANTAGONISTS -BETA BLOCKERS CAI INCREASED OUTFLOW ADRENERGIC AGONISTS (NON SELECTIVE) PILOCARPINE PROSTAGLANDINE DERIVATIVES

ANGLE GLOSURE GLAUCOMA ACUTELY PAINFULL RED EYE !! LOSS OF VA, CLOUDY CORNEA, NON REACTIVE PUPIL, LOSS OF RED REFLEX

MANAGEMENT DIAGNOSIS TOPICAL & SYSTEMIC PRESSURE REDUCTION PILOCARPINE (REDUCE PUPIL BLOCK) SYSTEMIC ANALGESIC & ANTI-EMETICS LASER PI

a. Cutting of deep block - anterior incision b. Posterior incision d. Peripheral iridectomy e. Suturing of flap and reconstitution of anterior chamber f. Suturing of conjunctiva c. Excision of deep block f d ba c e SURGERY: Technique

GLAUCOMA OPEN ANGLE SECONDARY GLAUCOMAS ANGLE CLOSURE

Sturge-Weber syndrome Congenital, does not blanche with pressure Associated with ipsilateral glaucoma in 30% of cases Naevus flammeus CT scan showing left parietal haemangioma Complications - mental handicap, epilepsy and hemiparesis Meningeal haemangioma Port-wine stain

Fibroma molluscum in NF-1

Iris melanoma Usually pigmented nodule at least 3 mm in diameter Invariably in inferior half of iris Occasionally non-pigmented Surface vascularization Angle involvement may cause glaucoma Pupillary distortion, ectropion uveae and cataract