Term
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Definition
decreased/no drainage of aqueous humour increases IOP - compression of retina and optic nerve
**Damage is permenant, begins w/ peripheral vision |
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Term
| What are the types of glaucoma? |
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Definition
- Open angle - unknown cause
- Closed angle - blockage of trabecular mesh
- Congenital - defect in outflow channels
- Secondary - drugs: steroids (open angle), anticholinergics/sympathomimetics (closed angle), diabetes |
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Term
| How does the aqueous humor drain? |
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Definition
Anterior segment has anterior and posterior chamber - ciliary process makes. Drainage via canal of schlemm through trabecular mesh or uveal scleral route
- made in posterior chamber, activation of beta receptors. Na/K ATPase pump |
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Term
| How is aqueous humor made? |
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Definition
- Active transport/secretion - bulk. Na/K ATPase, carbonic anhydrase, alpha and beta receptors
- Diffusion of lipophilic substances
- Ultrafiltration - water soluble, passive
**Outflow through trabecular mesh via canal of schlemm, or through uveoscleral/suprachoridal space |
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Term
| What is aqueous humor composition/function? |
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Definition
- slightly more acidic than plasma, less protein
- Maintain IOP ~16, provide nutrients to cornea and lens, remove waste |
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Term
|
Definition
14-16 - changes w/ pulse, BP, cough, posture, neck compression
- highest in AM
**Not used for diagnosis. Goal: increase drainage or decrease production |
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Term
| What is normal tension glaucoma and ocular htn? |
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Definition
- Normal tension glaucoma - IOP < 21, but visual field loss
- Ocular HTN - IOP > 21, no visual changes |
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Term
| What is the cause of open angle glaucoma? |
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Definition
Unknown! The drainage of aqueous humor is blocked, increasing IOP, leading to damage of the optic nerve that is permanent.
**Closed angle - iris blocks trabecular mesh. IOP increases dramatically |
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Term
| How are drugs absorbed through the cornea? |
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Definition
- Lipophilic - epithelium and endothelium
- Hydrophilic - Stroma
**Goal: Lower IOP by increasing ouflow or decreasing production |
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Term
| What are topical prostaglandin analogues for glaucoma? |
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Definition
- Latanoprost/Xalatan
- Bimatoprost/Lumigan
- Travoprost/Travatan Z
** Prodrugs that activate in the cornea. increase uveoscleral outflow by agonizing FP, increasing MMPs, and relaxing ciliary muscle
**AE: redness, eyelash growth, iris pigmentation |
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Term
| What beta blockers are used for glaucoma? |
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Definition
Nonselective:
- Timolol (Timoptic, Betimol)
- Levobunolol (Betagan)
- Metipranolol (Optipranolol)
- Carteolol (Ocupress)
Selective:
- Betaxolol (Betoptic)
**Decreases rate of AH production - beta receptor mediated production, reduction of blood flow.
- Timolol, metipranolol, and betaxolol are neuroprotective |
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Term
| What are AEs of topical beta blockers? |
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Definition
- Stinging
- Inflammation
- Conjunctivitis
- Systemic: bradycardia, bronchospasm, hypotension, impaired hypoglycemia recovery
**Amino groups promote selectivity, S-OH = potency |
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Term
| What are non-selective alpha agonists for glaucoma? |
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Definition
-Dipivefrin/epinephrine (Propine)
A prodrug converted to epi in the cornea. Increases outflow through both pathways and decr production of AH
**AE:hypersensitivty, deposits, incr BP, perspiration |
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Term
| What are alpha2 agonists for glaucoma? |
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Definition
- Apraclonidine/Iopidine - an amino group decreases lipophilicity
- Brimonidine/Alphagan P
Lowers IOP by reducing cAMP - decr production, vasoconstriction decr blood flow
**Brimonidine crosses BBB: fatigue, dizziness, dry mouth |
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Term
| What are topical carbonic anhydrase inhibitors for glaucoma? |
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Definition
- Brinzolamide/Azopt
- Dorzolamide/Trusopt - Sulfyl moity allows binding to enzyme, amino group prevents systemic effects
- Timolol + Dorzolamide/Cosopt
**Decr AH production by inhibiting CAH |
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Term
| What are SYSTEMIC carbonic anhydrase inhibitors for glaucoma? |
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Definition
- Acetazolamide/Diamox
- Methazolamide/Neptazane
**Decr IOP by inhibiting CAH - systemic acidosis possible |
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Term
| What are cholinomimetics for use in glaucoma? |
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Definition
Direct acting on M3: Can cause miosis, headache
- Carbachol/Miostat
- Pilocarpine/Pilocar
Indirect acting on cholinesterase inh. AEs severe - cataracts
- Ecothiophate/Phospholine
**Incr AH outflow through trabecular mesh. |
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