What is necessary to maintain IOP?
Production must equal drainage
AH is secreted by ____ into the posterior chamber
Ciliary epithelial lining the ciliary processes
Conventional pathway
After TM-> it will drain into schlemm’s Canal into collector channels into aqueous veins -> EPISCLERAL VENOUS CIRCULATION ->anterior ciliary & superior ophth. veins-> cavernous sinus
Both ways the aqueous leaves the eye includes
Passive flow
Conventional pathways is _____ of pressure
Dependent
Episcleral venous circulation role
Important role in conventional pathway in speed/magnitude of the outflow
Major resistance to outflow in conventional/TM pathway
Juxtacanicular and endothelial layer of schlemm’s canal
Unconventional/ Uveal scleral pathway is _____ of pressure
Independent
Uveoscleral pathway can be increase by
Cholinergics & prostaglandins
Uveoscleral pathway can be decreased by
Aging, muscle will become more fibrotic and elastic will thicken causing less outflow
-ciliary contraction
Autonomic nervous system also plays role in production & drainage of AH (neural regulation)
PNS Adrenergic Serotonergic Dopaminergic Prostaglandins
Primary route of drainage of AH
TM
- pressure dependent
- hydrostatic pressure
Secondary route of AH drainage
Uveal scleral outflow
- independent on pressure
- muscle
- decreases with age and ciliary contraction
TM outflow is dependent on hydrostatic pressure which is the difference between
IOP & episcleral veins
Ciliary muscle contraction effect on TM & uveoscleral pathway
Increased outflow in TM
Decreases outflow in uveal scleral
Goldmann equation
P(IOP) = (F/C) + P(EVP)
F rate of aqueous formation
C facility of outflow
Primary determinant of IOP
AH outflow resistance is the primary determinant of IOP
Outflow facility/resistance equation
P0= (F/C) + P v
3 Levels of aqueous outflow regulation
Trabecular meshwork
Uveoscleral pathway
Episcleral vendors pressure
Most important AH regulation
Episcleral venous pressure
