OPHTHALMOLOGY Glaucoma MBChB 4 Prof P Roux 2012. WHAT IS GLAUCOMA? A GROUP OF DISEASES IN WHICH...
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Transcript of OPHTHALMOLOGY Glaucoma MBChB 4 Prof P Roux 2012. WHAT IS GLAUCOMA? A GROUP OF DISEASES IN WHICH...
OPHTHALMOLOGYGlaucoma
MBChB 4Prof 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:
PRODUCTIONOUTFLOW
•SECRETION•ULTRAFILTRATION
•TRABECULAR MESHWORK(ANGLE)
•UVEOSCLERAL PATHWAY
Aqueous outflowAnatomy
a - Uveal meshworkb - Corneoscleral meshworkc - Schwalbe lined - Schlemm canale - Collector channelsf - Longitudinal muscle of ciliary bodyg - Scleral spur
c - Iris outflow
a - Conventional outflowb - Uveoscleral outflow
Physiology
•OPEN-ANGLE•ANGLE-CLOSURE
•PRIMARY•SECONDARY
•CONGENITAL•INFANTILE•JUVENILE•ADULT
CLASSIFICATION:
ACCORDING TO:
ANGLE ASSOCIATED FACTORS AGE 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
c d
a b
ANGLE
SECONDARY GLAUCOMAS1. 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 withaxoplasmic 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
GoldmannContact applanation
PerkinsPortable contact applanation
Pulsair 2000 (Keeler)Air-puff
Schiotz
Portable non-contact applanation
Non-contact indentation
Contact indentation
Tono-PenPortable
contact applanation
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
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
Horizontalraphe
Papillomacularbundle
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 deeperpunched-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
SURGERY Trabeculectomy
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
ANGLECLOSURE
SECONDARYGLAUCOMAS
OPEN ANGLE
GLAUCOMA
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-winestain
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