Glaucoma Flashcards
What is Glaucoma?
An optic neuropathy
Glaucoma is associated with:
Characteristic damage to the:
1) Optic nerve head (Cupping)
2) Visual field (Nerve fibre bundle defects)
Glaucoma is a blinding disease. How does it progress?
First the peripheral visual field becomes constricted, followed by loss of central visual acuity
Is an elevated eye pressure necessary to diagnose glaucoma?
No
What is the main risk factor for glaucoma?
The level of the intraocular pressure
What do we do to classify the glaucoma type?
Gonioscopy
What determines the stage of the glaucoma?
The extent of damage to the optic nerve and visual field
The most important intraocular pressure variable is the:
Amount of aqueous humor
The pathology of elevated intraocular pressure is due to:
Inadequacies of aqueous outflow rather than production
Gold standard for measuring intraocular pressure is:
Goldmann Applanation Tonometry (GAT)
The aqueous humor is produced by:
The non-pigmented epithelium of the ciliary processes
What is Primary Open Angle Glaucoma POAG?
Idiopathic increase in outflow resistance
What are the causes of Secondary Open Angle Glaucoma SOAG?
1) Clogging of trabecular meshwork
2) Increased episcleral venous pressure (EVP)
3) Scarring of the trabecular meshwork
4) Increased trabecular meshwork resistance due to medications (steroids)
What causes Increased episcleral venous pressure (EVP)?
1) Carotid cavernous fistula
2) Sturge Weber Syndrome
3) SVC obstruction
What are some risk factors for Closed Angle Glaucoma?
1) Anatomic features predisposing to angle closure
2) Advanced age (>60 years)
3) Female gender
4) Inuit and Asian ethnicity
5) Eye injury with scarring and adhesions
6) Rubeosis iridis
7) Drugs: Sulfonamides, TCA, MAOi, antihistamines
8) Mydriasis
Pathophysiology of Closed Angle Glaucoma?
Blocked trabecular meshwork → decreased drainage of aqueous humor from the eye → sudden ↑ in IOP
Primary Closed Angle Glaucoma cause?
Chamber angle is narrowing due
to the peripheral iris obstructing the trabecular meshwork
Complication of Acute Angle
Closure Attack?
Irreversible damage of the optic nerve
Treatment of Acute Angle
Closure Attack?
1) Lower IOP
2) Break the angle closure cycle:
a) YAG laser Iridotomy/Surgical iridectomy
3) Examine second eye and treat prophylactically
How can you lower the IOP in Acute Angle
Closure Attacks?
1) Systemically:
a) IV Acetazolamide/Mannitol
b) Oral Acetazolamide
2) Topical Eye drops:
a) α agonists
b) B Blockers
c) Carbonic anhydrase inhibitors
d) Pilocarpine
A thin cornea can give a falsely __(high/low) IOP reading, while a thick cornea can give falsely __(high/low) IOP
Low; High
Signs of glaucoma?
1) Increased C:D
2) Thin rim
3) Notching
4) Hemorrhages
5) ISNT rule
Optic nerve damage in glaucoma is ___(irreversible/reversible)
Irreversible
Medical treatment for glaucoma?
1) Prostaglandin analogues (PGAs)
2) Beta Blockers
3) Alpha-2 agonists
4) Carbonic Anhydrase Inhibitors
5) Parasympathomimetic / Cholinergic agonists
How do Prostaglandin analogues (PGAs) help in glaucoma?
Increases uveoscleral outflow
One drawback of Prostaglandin analogues (PGAs)?
Proinflammation = hyperemia
How do B-blockers help in glaucoma?
Decrease aqueous production
Carbonic Anhydrase Inhibitors are contraindicated in which patinets?
Those with a sulfa allergy
Laser treatments that increase outflow facility for glaucoma are:
1) Trabeculoplasty
2) Iridotomy
Laser treatments that decrease aqueous production for glaucoma are:
Cyclodiode laser
What are the surgery options for glaucoma?
1) Trabeculectomy
2) Glaucoma Drainage Devices
