Aqueous Outflow + 3 slides of Production

What is the conventional flow

trabecular meshwork

uveal meshwork→ corneoscleral meshwork→ juxtacanilicular tissue→ Schlemm’s canal→ collector channels→ scleral venous plexi→ episceral veins or Schlemm’s canal → aqeous veins→ episcleral veins

conventional outflow

does more outflow occur through TM or Uveoscleral?

TM, but it can be variable

What influences lead to reduced uveosceral outflow

age, ocular hypertension

what variables lead to increased uveosceral outflow

uveitis

how can we lower IOP by increasing aqueous outflow

prostaglandin analogs, alpha 2 agonist, MIGS procedure

what procedures lower aqueous production

endoscopic cyclophotocoagulation (ECP) and cycloablation

what is ECP

laser to ablate ciliary epithelium

what is cycloablation?

similar to ECP, but done through sclera

what procedures enhance outflow of aqueous

trabeculectomy-fista, tube/shunt 

what is the mean IOP

15.5 mm Hg

what are the two standard deviations for IOP

11-21

when is IOP the highest

at night or in the early morning hours

what does IOP fluctuate with?

circadian rhythm, long term variations- age, medications 

is IOP higher when laying down or sitting up?

laying down

what does IOP depend on

the balance between aqueous inflow and outflow

Less aqueous production means

less fluid entering the eye

outflow remains the same, what happens to overall fluid volume

decreases

reduced aqueous volume, the IOP is

low

What receptor will increase aqueous humor production

beta 2 receptor acitvation

what receptor being activated will lower aqueous production?

alpha-2 receptor

alpha 2 receptor activation causes what

adenylate cyclase to be inhibited

once adenylate is inhibited, what happens?

decreased cAMP

beta 2 receptor activation stimulates or inhibits adenylate cyclase

stimulates

stimulates adenylate cyclase leads to increase/decrease of cAMP

increase

to lower IOP what would we want to do to the alpha 2 receptor?

stimulate it

to lower IOP what would we want to do to the beta receptor

inhibit

what is an example of an alpha 2 agonist 

brimonidine 

what is a common beta blocker

timolol

where are adrenergenic receptors

ciliary epithelium

aqueous production is decreased by inhibiting what formation

bicarbonate

what reduces bicarbonate production?

inhibition of carbonic anhydrase 

inhibition of carbonic anhydrase slows

ion and fluid transport across the ciliary epithelium