Intro to Multifocals L1 Flashcards
What Options are available for Presbyopic Pxs?
-Single Vision
-Bifocals
-Trifocals
-Occuaptional Lenses
Varifocals
Pros and Cons of Single vision sep pairs?
Pros - cheaper, whole lens dedicated for specific rx, easy to explain
Cons - 2 or 3 sep pairs
px - anyone
Pros and Cons of Bifocals?
Pros - one pair of glasses, larger area for dist and near
Cons - shows age, jump, no intermediate
px - varifocal non tols
Pros and cons of Trifocals?
Pros - one pair of glasses
Cons - jump
px - varifocal non tols
Pros and cons of Occupational lenses?
Pros - one pair of glasses (int and near)
Cons - cant drive in them
Varifocals
Pros - one pair of glasses
Cons - distortion, takes a while to adapt to
px - over 45 generally
R seg
Cosmesis - good, segment not as noticeable
Vision - seg exerts base down prism - good for +ve lenses
D seg
Cosmesis - reasonable, straight line is noticeable
Vision - seg exerts small amount of base up prism, good for minus lenses
C seg
Cosmesis - better than D segs, curved top not as noticeable
Vision - Base UP, good for minus lenses
Executive
Cosmesis - poor, straight line noticeable
Vision - good optics, no jump
Where do you measure the seg top position for a bifocal?
LOWER LIMBUS
- prob with measuring from lower eyelids with older pxs is the eyelids tend to droop more which means seg is set too low and px sets head back slighlty when reading
- however if seg is set at that point from a previous dispense, keep it the same when dispensing
When would a px prefer a larger segment?
More reading area/ near work, prolonged reading, convergence error
What are the disadvantages of a larger segment?
Larger jump, looks ugly, more expensive, weight, more diff to order
When would you want the seg top to be lower?
Golfer, not needing the reading section as much
