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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
Physiology
a - Conventional outflow
b - Uveoscleral outflow
c - Iris outflow
CLASSIFICATION:
ACCORDING TO:
ANGLE
ASSOCIATED FACTORS
•PRIMARY
•OPEN-ANGLE
•ANGLE-CLOSURE •SECONDARY
AGE OF ONSET
•CONGENITAL
•INFANTILE
•JUVENILE
•ADULT
ANGLE
a
b
Open-angle
a. Pre-trabecular - membrane over
trabeculum
b. Trabecular - ‘clogging up’ of
trabeculum
c
d
Angle-closure
c. With pupil block - seclusio pupillae
and iris bombé
d. Without pupil block - peripheral
anterior synechiae
ASSOCIATED FACTORS
SECONDARY GLAUCOMAS
1. Pseudoexfoliation glaucoma
2. Pigmentary glaucoma
3. Neovascular glaucoma
4.
5.
6.
7.
8.
Inflammatory glaucomas
Phacolytic glaucoma
Post-traumatic angle recession glaucom
Iridocorneal endothelial syndrome
Glaucoma associated with iridoschisis
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
Air-puff
Non-contact
indentation
Perkins
Portable contact applanation
Pulsair 2000 (Keeler)
Portable
non-contact applanation
Schiotz
Contact indentation
Tono-Pen
Portable
contact applanation
Goniolenses
Goldmann
•
•
•
•
•
Single or triple mirror
Contact surface diameter 12 mm
Zeiss
Four mirror
• 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
•
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
Papillomacular
bundle
Horizontal
raphe
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
Types of physiological excavation
Small dimple central cup
Larger and deeper
Cup with sloping temporal
punched-out central cup wall
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
TREATMENT OF GLAUCOMA
MEDICAL
1
2
SURGERY
Trabeculectomy
LASER
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
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
OPEN ANGLE
GLAUCOMA
ANGLE
CLOSURE
SECONDARY
GLAUCOMAS
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
Fibroma molluscum in NF-1
Iris melanoma
• Usually pigmented nodule at
• Occasionally non-pigmented
least 3 mm in diameter
• Surface vascularization
• Invariably in inferior half of iris
• Angle involvement may cause• Pupillary distortion, ectropion
glaucoma
uveae and cataract
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