Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 44 Primary Angle Closure Glaucoma 1 Lecture Notes
Department of
Ophthalmology
Objectives
? At the end of this class the students shal be able
to :
? Define primary angle closure glaucoma.
? Understand the pathophysiology and the risk
factors.
? Be able to classify primary angle closure
glaucoma.
? Understand the fundamentals of managing
primary angle closure glaucoma
DEFINITION
? Primary angle closure glaucoma is a type of
primary glaucoma(with no obvious systemic or
ocular cause) characterized by
occludable/closed angles leading to
obstruction of aqueous outflow resulting in
rise of intra ocular pressure, optic nerve
damage and visual field defects.
ANGLE OF ANTERIOR CHAMBER
? STRUCTURES
? Schwalbe's line
? Trabecular meshwork
? Scleral spur
? Ciliary body band
? Root of iris
DRAINAGE OF AQUEOUS HUMOR
PRIMARY ANGLE CLOSURE
GLAUCOMA
EPIDEMIOLOGY
? PACG is the major cause of glaucoma blindness
worldwide.
? Age :- Average age at presentation 50-60 yrs
? Gender :- F > M, 4 : 1
? Race :-seen commonly in South-East Asian
population, Chinese and Eskimos
? Heredity :- mostly sporadic but may be inherited
AD/AR
? first degree relatives are at increased risk.
? Refractive error :- more common in
hypermetropes
Ocular risk factors
1. Shallow anterior chamber both
centrally and peripherally.
2. Decreased anterior chamber volume.
3. Short axial length of the globe.
4. Small corneal diameter.
Ocular risk factors
5.Decreased posterior corneal radius of
curvature
6.Anterior position of the lens with respect to
the ciliary body.
7.Increased curvature of the anterior surface &
thickness of lens
PATHOGENESIS
? It is incompletely understood.
? a. Iris?pupil obstruction (e.g., `pupil ary block')
? b. Ciliary body anomalies (e.g., `plateau iris syndrome')
? c. Lens?pupil block (e.g., `phacomorphic block' (swollen
lens or microspherophakia))
? Relative Pupillary block
? Normal y the pressure in the post. chamber exceeds that in the ant.
chamber due to physiological degree of resistance at the pupil ,since the
iris rests posteriorly on the anterior lens capsule.
Anterior Iris Bowing
Simultaneous dilatation of the pupil renders the peripheral
iris more flaccid. The pupil block causes the pressure in the
Posterior Chamber to increase & peripheral iris bows
anteriorly
Iridocorneal contact
Eventually the iris touches the posterior corneal surface,
obstructing the angle and the IOP rises.
(Figures and photographs- Courtesy : Kanski's Clinical Ophthalmology)
Precipitating factors
1. Factors that produce mydriasis
? Dim illumination
? Emotional stress(due to increased sympathetic tone)
? Drugs
? Mydriatic agents :
? cyclopentolate, tropicamide, atropine, homatropine.
? Antipsychotic agents
? Phenothiazines: e.g., perphenazine ,fluphenazine
? Anticonvulsants e.g., Topiramate
? Antidepressants
? Tricyclic agents: amitriptylene ,imipramine
? Non-tricyclic agents: fluoxetine
? Antiparkinsonian agents : Trihexyphenidryl
? Antispasmolytics : Propantheline ,Dicyclomine
? Sympathomimetic agents : Adrenaline (epinephrine),
ephedrine, phenylephrine.
CLASSIFICATION
A. Primary angle-closure disease
? Irido-trabecular contact is the final common pathway of
angle closure disease, obstructing aqueous outflow
1. New classification
Primary angle closure suspect/PACS
Primary angle closure/PAC
Primary angle-closure glaucoma/PACG
2. Old classification
Angle closure suspect
Intermittent (sub acute) angle closure
Acute angle closure
Chronic angle closure
Absolute angle closure
New classification of PACG
qPrimary angle closure suspect/PACS
Has occludable/narrow angles
qPrimary angle closure/PAC
Has occludable/narrow angles +
High IOP/Peripheral anterior synechiae/
Excessive trabecular meshwork
pigmentation
qPrimary angle-closure glaucoma/PACG
PAC+ Optic disc changes+ Visual field
defects
Gonioscopic grading of Angle
closure
? Several grading systems :- Shaffer's, Spaeth's,
Scheie's.
? Shaffer's grading
Grade Angle width configuration
Chances of
Structures visible
closure
IV
35?-45?
Wide open
Nil
SL,TM,SS,CBB
I I
20?-35?
Open angle
Nil
SL,TM,SS
I
20?
Moderately open Possible
SL,TM
I
10?
Very narrow
Highly likely
SL only
0
0?
Closed
Closed
None
---------
Grade
IV
II
II
I
0
Van Herrick's grading
Tests for Angle closure
? Eclipse test : uses flash light to make a rough
assessment of angle depth
? Provocative tests for PAC suspects
?Prone- darkroom test: An increase in IOP of more
than 8mm Hg after one hour suggests PAC
?Mydriatic provocative test: Not preferred now
qFincham's Test: Also known as stenopaeic-slit test.
Glaucomatous halos remain intact , whereas
halos due to cataract are broken up into segments
PRIMARY ANGLE CLOSURE GLAUCOMA SUSPECT
? Also known as Latent PACG
? Essentially, the term implies
an anatomically predisposed
eye.
? Symptoms :- absent
? Signs :
? Axial AC depth is < normal
& iris lens diaphragm is
convex
? Close proximity of the iris
to the cornea
? Gonioscopy :- occludable
angle(grade 1 or 0)
without indentation in at
least 3 quadrants.
?Clinical course without
treatment may be:
IOP may remain normal
Acute or sub acute angle
closure may ensue
Chronic angle closure may
develop, without acute or
sub acute stages.
? Treatment
? Without treatment , risk of an acute pressure rise during the next
5 years is about 50 %.
? The need to treat is based on following criteria:-
? If one eye has had acute or subacute angle closure, then
fellow eye should undergo prophylactic peripheral laser
iridotomy (Laser PI)
? If both eyes have occludable angles, laser PI may be done
INTERMITTENT(SUBACUTE)PRIMARY ANGLE CLOSURE
GLAUCOMA
? A form of pupillary block glaucoma, which may not have
any recognizable symptoms.
? Occurs in a predisposed eye with an occludable angle in
association with intermittent pupillary block.
? Precipitating factors :- physiological mydriasis , or
physiological shallowing of AC when patient assumes a
prone or semi prone position ;emotional stress.
? Symptoms
? Characteristic h/o transient blurring of vision with haloes
around lights
? Ocular discomfort or frontal headache
? Attacks are recurrent and are usually broken after 1-2 hrs by
physiological miosis.
? Signs
? During an attack , eye is usually white
? In between attacks, eye looks normal although the angle is
narrow.
? Clinical course
? Without treatment is variable
? Some eyes develop an acute attack
? Others chronic angle closure
? Treatment:- Prophylactic laser PeripheraI Iridotomy(PI)
ACUTE PRIMARY ANGLE CLOSURE GLAUCOMA
? Sight threatening emergency
? Painful loss of vision due to sudden and total
closure of the angle.
? VA usually 6/60-Hand Movements.
? IOP is usually very high (40?70 mmHg).
Findings during an acute attack of angle-closure glaucoma
? Two of the following symptom sets:
? Periorbital or ocular pain
? Diminished vision
? Specific history of rainbow haloes with blurred vision
? IOP > 21 mmHg plus three of the following
findings:
? Ciliary flush (perilimbal conjunctival hyperemia)
? Corneal edema (epithelial,stromal)
? Shallow anterior chamber
Findings during an acute attack of angle-closure glaucoma
? Anterior chamber cell and flare
? Mid-dilated ,vertically oval and sluggishly reactive
pupil
? Closed angle on gonioscopy
? Hyperemic and swollen optic disc(due to
decreased axoplasmic outflow)
? Constricted visual fields
? MANAGEMENT
? Patient comfort ,lowering of the IOP and to break acute
attack-- main priorities.
? A. Immediate medical treatment
1. Patient should lie supine to allow the lens to shift
posteriorly.
2. Acetazolamide 500 mg orally(if there is no vomiting).
or I.V Mannitol 20% 1-2 g/kg over 1 hour (rule out
contraindications)
3.Topical
Prednisolone or dexamethasone q.i.d (if AC reaction)
Timolol (if there is no contraindication).
4. Analgesia and emetics as required.
? B. Subsequent medical treatment
Pilocarpine 2% q.i.d. to the affected eye and 1% q.i.d. to the
fellow eye.
Topical steroids (prednisolone 1% or dexamethasone 0.1%)
q.i.d. if the eye is acutely inflamed.
Timolol 0.5% b.d.,
and oral acetazolamide 250 mg q.i.d. may be required.
? If the above measures fail:
? Laser iridotomy or iridoplasty after clearing corneal oedema with
glycerol.
? Surgical options in resistant cases include lens extraction,
goniosynechiolysis, trabeculectomy and cycloablation.
? Findings suggestive of previous episodes of acute
angle closure glaucoma
? Descemets Membrane folds
? Fine pigment granules on corneal endothelium
? Peripheral anterior synechiae
? Posterior synechiae
? Glaucomflecken
? Sectoral/generalized iris atrophy
? Fixed and semi dilated pupil
? Optic nerve cupping &/or pallor
? Gonioscopy shows narrow angle
or PAS
? Visual field loss
Chronic angle closure glaucoma
? Visual Acuity is normal unless damage is
advanced.
? Anterior chamber is shal ower in pupil ary
block than non-pupil ary block.
? Optic nerve signs depend on severity of
damage.
? IOP elevation may be only intermittent.
? Gonioscopic abnormalities-Peripheral
Anterior Synechiae, narrow angle,
pigmentation of Schwalbe's line.
Treatment of chronic angle closure
? Medical treatment is similar to that of POAG
? Prostaglandin/Prostamides
Latanoprost, Bimatoprost, Travoprost
? Beta blockers
Timolol maleate, Betaxolol
? Carbonic anhydrase inhibitors
Dorzolamide, Brinzolamide
? Sympathomimetics
Brimonidine, Apraclonidine
? Parasmpathomimetics
Pilocarpine
? Oral carbonic anhydrase inhibitors
Acetazolamide, Methazolamide
Treatment of chronic angle closure
? Laser Peripheral Iridotomy (PI) in affected eye
along with Prophylactic PI in fellow eye
Laser Peripheral Iridotomy
? Complications of laser therapy
1. Bleeding
2. IOP elevation
3. Iritis
4. Corneal burns
5. Lens opacities
6. Glare and diplopia
? Surgical treatment
Trabeculectomy (filtering surgery) is the
surgical procedure of choice
? Success:- 87- 100 % with multiple operations
? Complications:-
? Flat AC, hypotony
? Bleb related infections
? Cyclodialysis
? PATIENTS REQUIRE REGULAR AND LIFE LONG
FOLLOW UP
Absolute glaucoma
? Is the final/last stage of PACG
? Clinical features:
? Painful blind eye
?Perilimbal reddish blue zone, due to dilated
anterior ciliary veins
?Cornea gradually becomes hazy, insensitive
with bullous keratopathy and filamentary
keratitis
?Anterior chamber is very shallow/flat
Clinical features of absolute glaucoma
? Iris is usually atrophic
?Pupil is fixed and dilated
?Glaucomatous optic atrophy of the optic disc
?High IOP
Management of absolute glaucoma
? Cycloablation/destruction of the secretory
ciliary epithelium
q Cyclophotocoagulation
q Cyclocryotherapy
q Cyclodiathermy
? Rarely
? Retrobulbar alcohol injection
? Enucleation of eyeball
Complications
? Corneal ulceration
? Staphyloma formation (Ciliary/Equatorial)
? Atrophic bulbi (Shrunken eye)
Conclusion
? Primary angle closure glaucoma is a
potentially sight threatening condition,
characterized by occludable anterior chamber
angles.
? Obstruction of aqueous outflow results in rise
of intra ocular pressure, optic nerve damage
and visual field defects.
? Management may include medical, laser
and/or surgical modalities.
This post was last modified on 07 April 2022