Final Flashcards
Metamorphopsia
Distortion
Threshold
Level where stimulus can be seen 50% of the time
Supra threshold
Stimulus can be seen 90-95% of the time
Scotoma
A VF defect, placed where an object can’t be seen
What is a blind spot and where is it physically?
A blind spot is where the optic nerve is placed.
Has very little photoreceptors
It is 3mm nasal to the fovea
Size of blind spot
How many points to plot a blind spot
1.5mm high and 1mm wide
A minimum of 8 points
What is an absolute Scotoma
Total blindness
What is a relative Scotoma
Can’t see lowly lit objects
Can only see when brighter and larger
What is a hysterical Scotoma
It’s a psychological problem
Not a real Scotoma
Constricting VF, spiral pattern
What is a scintillating Scotoma
Associated with margarines
Not painful.
Bright colors and zigzags
NPA
NPC
NEAR POINT ACCOMMODATION
NEAR POINT CONVERGENCE
How often should a keratometer need to be calibrated?
Every two months
What is a central Scotoma
Depressed vision with the fixation point
Interferes with central vision
What is Pericentral Scotoma
Fixation point relatively clear,
Surrounding field defect
Peripheral problems
Paracentral Scotoma
Depressed vf in to one side of fixation
Nasal or temporal
