NCT for Clerkships Flashcards
What things can create large changes in IOP?
Rate of filtration Change of rate of production Body position Blood pressure External pressure on the globe Central venous pressure
A decrease in filtration leads to a ___ in IOP.
Increase
According to the Beaver Dam Eye study, reduced IOP is associated with what?
Reduced systemic blood pressure
What is perfusion pressure?
The balance between the blood pressure and the IOP
What is the perfusion pressure equation?
Diasolic BP - IOP = perfusion pressure
What is autoregulation?
The intrinsic tendency of an organ to maintain constant blood flow despite changes in perfusion pressure to that organ by increasing vascular resistance of the smaller retinal vessels
What things may cause an IOP increase due to external pressure?
Blepharospam/forceful closure
Digital pressure
Tumor
Varix
How is central venous pressure calculated?
1/2 of IOP
What is central venous pressure?
The amount of blood flow at the vena cava returning to the heart
What does central venous pressure rise?
Too much IV fluid
Heart attack
When does central venous pressure decrease?
Blood loss
What is the glaucoma triad?
Increased IOP
Optic nerve damage
Visual function loss
An acute increase in IOP may cause what?
Nausea
Pain
Halos
What is phtisis bulbi?
When IOP is decreased to the point where the eye begins to “deflate”
When is IOP the highest?
Early morning