ANGLE CLOSURE GLAUCOMA

Ea Raksmey

First Year Resident

2014

Outline Anatomy IOP and Aqueous Humor Dynamics Pathophysiology Definition of Glaucoma Classification Diagnosis Medical Management Surgical Management

Anatomy

Ciliary Body:6-7 mm wideHas 2 parts:

○ Pars plana: Avascular, smooth pigmented4 mm wideFrom ora serrata to ciliary process

○ Pars plicata:Vascularized Has around 70 radial folds (ciliary process) Zonular fibers attachment

Anatomy Lined by 2 layers of epithelial cells

○ Nonpigmented Epithelium (NPE)○ Pigmented Epithelium (PE)

The apices of NPE and PE are fused together by a system of junctions and cellular interdigitations (Blood Aqueous Barrier)

Anatomy

Anatomy

Anterior ChamberBetween Cornea (front) and Iris (back)AC Angle lies at the corner of Cornea-Iris

junction, consists of: ○ Schwalbe Line○ Schlemm Canal and TM○ Scleral Spur○ Ciliary Process○ Iris

Anatomy

Anatomy

Schwalbe’s LineIs the anatomical line found on the interior

surface of the cornea, and delineates the outer limit of corneal endothelium layer.

It represents the termination of Descemet’s membrane

Anatomy

Trabecular MeshworkIs a circular spongework of connective

tissue lined by trabeculocytes, that have contractile properties and may influence outflow resistance

3 portions: ○ Uveal Portion○ Corneoscleral Meshwork○ Juxtacanalicular Tissue

Anatomy

Anatomy

Schlemm CanalCircular tube resembling a lymphatic vesselContribute to the pressure-dependent

outflow of aqueous

IOP and Aqueous Dynamics Aqueous Humor

Clear fluid that fills the PC and ACSecreted by ciliary epithelium (NPE) Flow rate 2-3 µL/mnFunctions:

○ Provide nutrients to avascular zones○ Remove metabolic wastes○ Maintain IOP○ Clear medium for transmission of light

IOP and Aqueous Dynamics

IOP and Aqueous Dynamics AH secretion into the PC result from:

Active Secretion: Na/K ATPase pump

Ultrafiltration: Hydrostatic/Oncotic pressure

Simple Diffusion: Different concentration

IOP and Aqueous Dynamics Outflow: 0,22-0,30µL/mn/mmHg

Pressure-dependant: ○ Trabecular-Schlemm canal pathway○ 80-95 % of outflow

Pressure-independent:○ Non-trabecular or uveal pathway○ 8-15 % of outflow

IOP and Aqueous Dynamics Composition of AH

Inorganic Ions:○ Na+, K+, Mg○ Ca+ ○ Cl-, HCO3-○ Iron, copper, zinc

Organic Ions: ○ Lactate and Ascorbic Acid

CarbohydratesGlutathione and UreaProteinsEnzymes

IOP and Aqueous Dynamics IOP: 11-21mmHg Balance between the aqueous inflow

and outflow Fluctuation:

Higher in morning, lower in noon and evening

Heart rateBlood pressureRespiration

Pathophysiology

Angle ClosureRefers to the occlusion of the TM by the

peripheral iris (Iridotrabecular Contact or ITC) Obstructing the aqueous outflow

Can be divided into two types:○ Primary ○ Secondary

Pathophysiology

Primary Angle Closure GlaucomaRisk Factors:

○ Race: Blacks 20-40 times higher than whites○ Gender: Women are more likely to have

PACG than men due to shallower AC○ Age: 55-65 years old○ Refraction: Hyperopic○ Inheritance: genetics

Pathophysiology

Secondary Angle Closure Glaucomacaused by impairment of aqueous outflow

secondary to apposition between the peripheral iris and the trabeculum

2 mechanisms:○ “Pushing” of Iris from behind

Pupillary block, plateau iris syndrome, malignant glaucoma, dislocated lens

○ “Pulling” of Iris forward Iris incarceration after trauma, migration of corneal

endothelium, epithelium downgrowth

Definition

Glaucoma is a group of diseases characterized by:Optic neuropathy with CDR >0,5Visual field lossColor vision defect+/- elevated IOP

Classification

Angle Closure GlaucomaPrimary Angle Closure Glaucoma

○ Acute Angle Closure○ Subacute Angle Closure○ Chronic Angle Closure

Secondary Angle Closure Glaucoma:○ With Pupillary Block○ Without Pupillary Block

Diagnosis

Primary Angle Closure GlaucomaAcute Angle Closure

○ Definition: IOP rises rapidly as a result of relatively sudden blockage of the TM by the iris

○ Symptoms:Ocular painHeadache Blurred visionRainbow-colored halos around lightsNauseaVomitting

Diagnosis○ Signs:

VA 6/60-HMHigh IOPCongested episcleral and conjuctival blood vesselsCorneal edemaShallow AC (aqueous flares and cells)Iris bombéMid-dilated, sluggish and irregularly shaped pupilGlaukomflecken

DiagnosisSubacute or Intermittent Angle Closure

○ Blurred visions, halo○ Mild pain by elevated IOP○ IOP is normal between episodes○ May to chronic angle closure glaucoma or

acute attack if not resolve spontaneously

DiagnosisChronic Angle Closure

○ May develop after acute attack in which synechial closure persists

○ Or after AC chamber close gradually or IOP slowly rises (Creeping Angle)

○ Resembles open angle glaucoma due to:Lack of symptomsModest IOP elevation Optic nerve damage Characteristic VF loss

Diagnosis

Clinical Evaluation: History Ocular ExaminationGonioscopyOptic NerveVisual Field Test

Diagnosis

Ocular ExaminationComplete ocular examinationAC:

○ Van Herick method:

Diagnosis Gonioscopy

DiagnosisShaffer System: angle between TM and iris

○ Grade 4:35-45 degreesWide open angle Visible up to iris roots

○ Grade 3: 25-35 degreesVisible up to scleral spurs

○ Grade 2:20 degreesVisible up to TM

○ Grade 1:10 degreesVisible up to Schwalbe line

○ Grade 0:Angle completely closed

Diagnosis

Focal ischemic disc Myopic disc with glaucoma Senile sclerotic disc Concentrically enlarging discs

Diagnosis

Baring of circumlinear blood vessels Bayoneting Collaterals Loss of nasal NRR Lamina dot sign Disc hemorrhage Sharpened edge

Diagnosis

Visual Field TestEarliest stepParacentralNasal step Arcuate-shapedEnlargement Deepening Ring scotoma End stage

Diagnosis

Secondary Angle Closure Glaucoma With Pupillary Block: Lens-Induced

○ Phacomorphic Glaucoma:

Diagnosis

Secondary Angle Closure Glaucoma With Pupillary Block: Lens-Induced

○ Ectopia Lentis

Diagnosis

Secondary Angle Closure Glaucoma Without Pupillary Block:

○ Neovascular Glaucoma○ Iridocorneal Endothelial Syndrome ○ Tumours ○ Inflammation ○ Malignant glaucoma (aqueous misdirection)

Treatment

Goal of treatment:Preserve visual function Lowering IOP Prevent VF lossNeuroprotection

Treatment

Medical management Decrease aqueous production:

○ Beta blockers○ Alpha agonist○ Carbonic anhydrase inhibitor

Increase uveoscleral outflow:○ PG analogs

Increase TM outflow:○ Parasympathomimetic

Induce intravascular osmolarity:○ Hyperosmotic agents

Treatment

Treatment

Surgical treatment Trabeculectomy Artificial filtering shunt

Laser: ○ Argon laser trabeculoplasty○ YAG laser iridotomy ○ Laser iridoplasty

FIN

References Section 2, Fundamentals and Principles of Ophthalmology.

(2010-2011). Singapore, the American Association of Ophthalmology

Section 10, Glaucoma. (2010-2011). Singapore, the American Association of Ophthalmology

Kenski, J. Jack. MD, (2011). Clinical Ophthalmology: A Systemic Approach, 7th Edition. Elsevier Saunders, UK.

Yanoff, M. and Duker, J. (2008). Yanoff & Duker: Ophthalmology, 3rd Edition. Elsevier Saunders, UK.

Ehlers, Justis, P.; Shah, Chirag, P. (2008). Will’s Eye Manual, The Office and Emergency Room Diagnosis and Treatment of Eye Diseases, 5th Edition. Lippincott Williams & Wilkins