Glaucoma Flashcards
Definition
A group of ocular diseases in which progressive optic neuropathy
leads to the loss of vision.
dont need to know pathophys
○ Often characterized by an increase in intraocular pressure that causes distinctive changes in the optic disc and loss of retinal nerve fibres
○ Loss of this neural tissue can lead to irreversible loss of visual field usually beginning peripherally, but becoming complete if the disease is unchecked.
○ Can be classified as open angle or closure-angle
Classification of Glaucoma
Open Angle Glaucoma - Caused by partial blockage of the drainage canal - the angle between the cornea and iris is still open slowed drianage
Angle Closure Glaucoma
- caused by a sudden and complete
blockage of the aqueous humor
drainage
Comparison of POAG & PACG
see slide 10
Primary Open Angle Glaucoma
(POAG)
risk factors
– Elevated IOP – Advanced age – Myopia (nearsightedness) – Black race – Family history of glaucoma – Disease (Hypertension, Diabetes, Migraines) – Drug Therapy
Primary Angle Closure Glaucoma
(PACG)
risk factors
– Female gender – Advanced age – Hyperopia (farsightedness) – Asian or Caucasion ethnicity – shallow anterior chamber – Eye trauma/ injury – Drug Therapy
What statements are false?
a. Closed angle glaucoma usually has no symptoms
b. Intraocular pressure is a non-modifiable risk factor
c. Optic nerve damage and retinal ganglion cell death
leads to visual defects
d. None of the above
A. closed angle glauc has no symptoms
?
Risk Factor: Drugs
Primary Open Angle Glaucoma
(POAG)
*● Ophthalmic corticosteroids (high risk) ● Systemic corticosteroids ● Nasal/inhaled corticosteroids ● Ophthalmic anticholinergics ● Succinylcholine ● Vasodilators (low risk) ● Cimetidine (low risk
Primary Angle Closure Glaucoma (PACG) ● *Topical or systemic anticholinergics ● *Topical or systemic sympathomimetics ● *Antihistamines ●* Tricyclic antidepressants ● *Serotonin-selective reuptake inhibitors ● Venlafaxine ● Topiramate ● Low-potency phenothiazines ● Benzodiazepines (low risk) ● Vasodilators (low risk) ● Monoamine oxidase inhibitors (low risk) ● Topical cholinergics (low risk)
Assessment
Ophthalmoscopy
• Optic disk exam (optic nerve head cupping)
• Tonometry – IOP
Note: Screening for ↑IOP alone is not diagnostic for
glaucoma. Up to half of patients with glaucoma have
normal IOPs (<21 mm Hg)
• Perimetry – visual field testing
Screening
• Consider for high-risk populations
(older adults, diabetes)
• Baseline eye exam should begin at age 40 if no other
risk factors for eye disease present
Goals of Therapy
- Lower IOP (a surrogate marker)
- Prevent or slow down the progression of vision loss
- Prevent or reduce any associated pain
- Improve patient’s quality of life
Treatment Progression: POAG
Stepwise Approach → Add 1st topical drug → Add 2nd/3rd topical drug → Add systemic drugs → Laser therapy → Surgery
Drug Therapy: POAG (6)
- Beta adrenergic antagonists
- Prostaglandin analogues
- Alpha-2 Adrenergic Agonists
- Carbonic Anhydrase Inhibitors
- Cholinergic Agonists
- Combination Topical Agents
- Beta-Adrenergic Antagonists
which line?
safety?
adherence?
Blockade of the beta-adrenergic receptors in the ciliary body leads to: ↓ aqueous humour production Examples: Timolol, Betaxolol
First line therapy:
- Efficacy (decreases IOP 20-30%)
- Safety: minimal ocular side effects, but there is potential for systemic side
effects which are associated with beta blockade (e.g.: bradycardia, hypotension, bronchospasm/ shortness of breath)
- Adherence (BID dosing, XR formulations)
Avoid in patients with asthma or severe chronic obstructive pulmonary disease; caution in patients with a history of syncope or bradycardia
AE
Ocular A/Es usually minimal: stinging, dry eyes, conjunctivitis (rare)
Systemic A/Es: bronchospasm, exacerbation of CHF, dyspnea, bradycardia, hypotension, syncope, depression, impotence, altered response to hypoglycemia
- Prostaglandin Analogs
which line?
safety?
adherence?
increases the uveoscleral outflow of aqueous humour ↑ drainage of aqueous humour Examples: Bimatoprost, Latanoprost, Travoprost
First line therapy:
- Efficacy (decreases IOP 25%-35%)
- Safety: Generally well tolerated with minimal systemic side effects (fewer than beta blockers)
- conjunctival hyperemia, burning, stinging, itching, iris pigmentation (can darken to brownish), increased eyelash length, headache, flu-like symptoms
- avoid in pregnancy
- Adherence (once daily dosing)
Latanoprost has reduced risk of conjunctival hyperemia
Travoprost is formulated with a non–benzalkonium chloride preservative
- Alpha-2 Adrenergic Agonists
which line?
safety?
adherence?
Suppresses the formation of and increases the uveoscleral outflow of aqueous humour
↓ aqueous humour secretion and
↑ drainage of aqueous humour Examples: brimonidine, apraclonidine
2nd line therapy:
- Efficacy: decreases IOP ~18-27% (less effective than 1st line agents)
- Safety: Allergic type reaction characterized by lid edema, eye discomfort, and
foreign-object sensation, itching, and hyperemia (can occur in up to ~⅓ of
patients on apraclonidine, less often with brimonidine)
- Systemic A/Es: dizziness, fatigue, dry mouth, BP/HR reduction
- Caution in patients with CVD, renal disease, and diabetes
- Adherence: BID and TID dosing
- Carbonic Anhydrase Inhibitors (CAIs)
which line?
safety?
adherence?
Inhibit aqueous production by blocking active
secretion of sodium and bicarbonate ions
from the ciliary body to the aqueous humor
↓ aqueous humour secretion and
Examples:
topical: dorzolamide, brinzolamide,
oral: acetazolamide, methazolamide
Topical CAIs: 2nd line therapy:
- Efficacy: decreases IOP 15-25% (less effective than 1st line agents)
- Safety: *generally well tolerated; local side effects include transient burning andstinging, blurred vision, and rarely, conjunctivitis or photophobia.
- Systemic A/Es: are unusual with topical CAIs
- Due to favorable adverse-effect profile, topical CAIs can be useful alternative monotherapy or adjunctive therapy
- Adherence: BID and TID dosing
4. Carbonic Anhydrase Inhibitors (Systemic) which line? safety? adherence?
Oral CAIs: 3rd line therapy:
- Efficacy: decreases IOP 25-40% (very effective)
- Safety: frequently produce intolerable adverse effects (systemic acidosis
symptoms such as malaise, anorexia, nausea, depression, decreased libido)
and other A/Es such as kidney stones and frequent urination.
- Adherence: BID to TID dosing
- Cholinergics
which line?
safety?
adherence?
Contracts the ciliary muscle and opens the
trabecular meshwork, thereby promotes the
outflow of aqueous humour
↑ drainage of aqueous humour
Example: Pilocarpine
Topical Cholinergic: 3rd line
- Efficacy: decreases IOP 20-30% (similar to beta blockers)
- Safety: miosis, accommodative spasms, frontal headaches, periorbital pain, eyelid twitching, and retinal tears/ detachments
- Systemic A/Es: diaphoresis, GI upset, urinary frequency, bronchospasm, and heart block.
- Adherence: TID to QID dosing
Poorly tolerated in children and
younger adults.
- Combination Topicals
which line?
safety?
adherence?
Fixed Combination Topicals
Indicated for: patients who require more than 1 agent to adequately reduce IOP
Efficacy: the combination of individual agents are all more effective than their respective individual agents
Safety: combination products reduce cumulative exposure to preservatives and prevent drug washout
Adherence: more convenient and may improve adherence for patients who require
more than 1 agent to adequately reduce IOP
Preservatives
Benzalkonium chloride is the most common preservative in eye drops
- Unfortunately, ~ 6% of glaucoma patients are allergic
- Prolonged exposure can result in superficial damage to the ocular surface,leading to irritation, dryness, itching, and burning
- Alternative preservatives/ products have been developed:
- Travatan Z (travoprost): an ionic buffer preservative
- Ibza (travoprost): POLYQUAD preservative
- Alphagan P (briminodine): purite preservative
- Monoprost (latanoprost): single use ampoules, preservative free
- Trusopt (dorzolamide): single use ampoules, preservative free
Non-Pharm Therapies
● Lifestyle modifications have not been shown to alter the outcome of the
disease. Aerobic exercise can lower IOP modestly in some patients with glaucoma.
● Laser or surgical procedures are treatment options if drug therapy is
unsuccessful or not tolerated by the patient
Monitoring and Targets
Poor Response?
IOP: ↓ of >20% from baseline depending on severity
Disk cupping: <0.5
Perimetry: minimal vision loss
- Check adherence
- Assess technique
- Monitor for side effects
- Change to or add another agent
Laser/ Surgery
Laser Trabeculoplasty
- Open-angle glaucoma
- Laser is applied to trabecular meshwork (drainage system).
- First line for elderly, poor adherence, or POAG. Effect is short term (2yr)
Iridectomy
- angle-closure glaucoma
- Used in affected eye and prophylactically in other ey
Cannabis?
The COS (Canadian Ophthalmological Society) does NOT support the use of
cannabis (marijuana) for the treatment of glaucoma7
- Has short duration of action and undesirable psychotropic and other systemic side effects.
- Regulation of IOP by THC and CBD is complex and not fully understood
- Other more effective and less harmful treatments exist.
Acute Closure Glaucoma (PACG)
types of tx used
Goal of initial treatment: rapid reduction of IOP 3, 7
- Aggressive medical treatment is used until an iridectomy is performed
- Pilocarpine 1% - 4% gtts q5min for 4-6 doses
- Acetazolamide 250 mg p.o. or 500 mg injectable preparation
- Secretory inhibitors (Beta blockers, a2-agonists, topical CAIs)
- Hyperosmotic agents (Mannitol 15%, 20%, or 25%:1.5 -2 g/kg infused
IV over 30-60 min)
- Hypertonic saline 3%: 3ml/kg IV over 20-30min
Surgical intervention (iridectomy or iridotomy) must be performed before the iris
and outflow channel become permanently closed.
