23- Ansi Standards Flashcards
What do the Ansi Standards do?
Include tolerance charts and rules to make sure eyeglasses have been made correctly.
What prescription form MUST the rx be in according to ANSI?
Minus cylinder Form
You must use a calibrated lensmeter, focimeter or vertometer to check the power of SVD or multifocals T/F
TRUE
What is the relationship between DRP/MRP/OC and prism according to ANSI standards? 2
If prism is present DRP/MRP is at some point on the lens other than the OC
DRP/MRP is at the same point to the OC if no prism is required
Practice examples of seeing if RXs are in or out of ANSI standards
During Ansi standards we must explain WHY they do/don’t pass the ANSI standards. T/F
True
When finding if the cyl is out of ANSI standards what must we do?
Find the difference between the two powers (Transpose) use that difference for the tolerance chart. Should be the same as the cyl measurement
Where is the add power measured according to ANSI standards?
The surface that contains the segment or progressive addition surface
In a progressive of medium to high plus power lenses where do we measure the add power ?
Front surface
Where is the add power measured in a progressive ?
Usually back surface.
What does nominal mean in regards to add?
Total add power
When looking if the add power is out of ANSI what do we look at?
Total add power
sph and add together
Review steps for spotting a lens in powerpoint
What does the ANSI standards check in regards to prism?
The amount of induced prism in a when the PRP is wider, narrower, higher or lower than what you have ordered
Where is prism neutralised in a single vision or multifocal lens?
at the PRP
