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30 Cards in this Set
- Front
- Back
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Glaucoma: Classification
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Open angle - primary, secondary
Angle closure - pupil blocked (primary, secondary), no pupil block (primary, secondary) Mixed mechanism Developmental |
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Glaucoma: Epidemiology
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Leading cause of irreversible blindness world wide
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Glaucoma: Definition
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irreversible and progressive diseas of the optic nerve characterized by typical optic disc cupping and visual field changes
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Glaucoma: Pathphysiology (theories)
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Slow death of retinal ganglion cells
Theories: Mechanical theory Vascular theory Excitatory theory |
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Glaucoma: Risk Factors
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Elevated IOP (21mmHg ULN) - most significant RF
Black race Family history of glaucoma Increased age |
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Aqueous Humour Flow
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Formed in ciliary body, flows around lens through pupil into A/C, drains through trabecular meshwork into canal of schlemm then into the blood
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Glaucoma: Minor Risk Factors
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Myopia, diabetes, hypertension, migraine
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Glaucoma: Diagnosis
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Full medical history (PAOG - no symptoms)
Vision (early PAOG - no defect) IOP Measurement Ocular Examination Other tests |
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Glaucoma: Diagnosis - ocular exam components
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IOP measurement
Anterior chamber angle exam Optic nerve head exam Visual field exam |
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Tools for measuring IOP
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Goldmann prism on slit lamp
Schiotz indentation tonometer Pachymetry - measures thickness of front of eye to correct the IOP score |
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Gonioscopy: definition and findings
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Device for examining anterior chamber angle
Normal = POAG Abnormal = SOAG Absent = Angle closure glaucoma |
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Glaucoma: Optic Nerve Changes
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Cupping - C:D >0.5
Disc asymmetry Notching Excavation Disc hemorrhage NFL defect |
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Glaucoma: Visual Field defect pathology
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Damage to arcuate nerve fibers results in arcuate loss of peripheral visual field
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Typical glauomatous field defect findings
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Arcuate
Paracentral Nasal step Constricted Loss of central vision (late) |
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Glaucoma: Therapeutic Strategies
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Medication
Laser Surgery |
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Glaucoma: Pharmacotherapy - 5 classes
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Beta blockers
Parasympathomimetics Carbonic anhydrase inhibitors Alpha agonists Prostaglandin agonists (hyperosmotics - ER only) |
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Glaucoma: Pharmacotherapy - beta blockers
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MOA - suppress fluid production
Non-selective or beta selective S/E: COPD bradycardia, heart block, depression, impotence Examples: Timolol, levobunolol, betaxolol |
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Glaucoma: Pharmacotherapy - parasympathomimetics
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MOA - increased outflow through TM
S/E: Miosis, accommodative spasm, headach, systemic cholinergic problems Example: pilocarpine |
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Glaucoma: Pharmacotherapy - carbonic anhydrase inhibitors
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MOA - Decreases aqueous production
Systemic or Local S/E: Systemic - LOTS! Local - topical blepharoconjunctivitis (allergy), foul taste, stinging and itch Examples: acetazolamide, dorzolamide, brinzolamide |
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Glaucoma: Pharmacotherapy - alpha agonists
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MOA: Decreased aqueous outflow and mild increased outflow
Non-selective or alpha-2 selective S/E: topical blepharoconjuncitivis Examples: epenephrine, brimonidine, apraclonidine |
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Glaucoma: Pharmacotherapy - prostaglandin agonists
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MOA: increases uveosacral outflow through cilliary muscle
S/E: iris colour change, lash growth, conjunctival hyperemia, periorbital skin pigmentation Examples: latanoprost, travoprt, bimatoprost |
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Glaucoma: Laser Therapy
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Laser Trabeculoplasty (improves flow through TM)
Laser cyclophocoagulation (ciliary body destruction) |
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Glaucoma: Surgical Therapy
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Trabeculectomy
Tube Shunt Placement |
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Acute Angle Closure: Pathophysiology
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90% due to pupil blockage between posterior iris and anterior lens
Aqueous fluid build-up pushes iris forward Blockage of Trabecular Meschwork (angle) |
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Acute Angle Closure: Risk Factors
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Hyperopia, increased age, female, family history, Inuit, Chinese
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Acute Angle Closure: Precipitating factors
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Dim illumination, emotional stress, drugs
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Acute Angle Closure: Symptoms
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Pain, redness, N/V, blurred vision
Rainbow vision prodrome |
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Acute Angle Closure: Signs
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Elevated IOP
Conjunctival herniation Cloudy cornea Shallow A/C (penlight exam) mid-dilated, unreactive, oval shaped pupil Flare and cells in A/C Closed angle gonioscopy |
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Acute Angle Closure: Management
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Instil topical antiglaucome meds (beta blockers, alpha agonists, carbonic anhydrase inhibitors)
Instill pilocarpine Establish IV Hyperosmotic agents if necessary REFER! |
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Angle Closer: Definitve Treatment
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Laser iridotomy
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