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OPHTHALMOLOGY Glaucoma

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.

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OPHTHALMOLOGY Glaucoma

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  1. OPHTHALMOLOGYGlaucoma MBChB 4 Prof P Roux 2012

  2. 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)

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

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

  5. CLASSIFICATION: ACCORDING TO: ANGLE ASSOCIATED FACTORS AGE OF ONSET • CONGENITAL • INFANTILE • JUVENILE • ADULT • PRIMARY • SECONDARY • OPEN-ANGLE • ANGLE-CLOSURE

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

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

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

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

  10. 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

  11. EXAMINATION • TONOMETRY (PRESSURE) • GONIOSCOPY (ANGLE) • VISUAL FIELD • OPTIC DISC (OPTIC NERVE)

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

  13. Goniolenses Goldmann Zeiss • Single or triple mirror • Four mirror • Contact surface diameter 12 mm • Contact surface diameter 9 mm • Coupling substance required • Coupling substance not required • Suitable for ALT • Not suitable for ALT • Not suitable for indentation gonioscopy • Suitable for indentation gonioscopy

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

  15. Humphrey perimetry

  16. Anatomy of retinal nerve fibres Papillomacular bundle Horizontal raphe

  17. Optic nerve head Small physiological cup a - Nerve fibre layer a b b - Prelaminar layer c - Laminar layer c Large physiological cup • 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

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

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

  20. TREATMENT OF GLAUCOMA MEDICAL 1 2 SURGERY Trabeculectomy LASER 3

  21. ANTIGLAUCOMA DRUGS • ALPHA-2 SELECTIVE ADR. AGONISTS - Alphagan • BETA-ADRENERGIC BLOCKING AGENTS - Betagan • CARBONIC ANHYDRASE INHIBITORS - Trusopt • PROSTAGLANDIN DERIVATIVES - Xalatan • PILOCARPINE • ADRENALINE

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

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

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

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

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

  27. Fibroma molluscum in NF-1

  28. 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

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