Question for a Lab Technician who's familiar with 360 degree system.

[rgreed]

Hi, I'm an inventor and am relatively familiar with the BU, BD, BO, BI system, but, I find that I need to learn the 360 degree system.

First: Is the following format correct?

Rx: OD 3.0 D Sph 11.5 Δ base 64.6°
OS 2.0 D Sph 7.7 Δ base 244.6°

Second: Is there an on line document that you could direct me to that clearly describes that system?

Thanks for any help.

Roger

[chip anderson]

simply subtract 180 degrees from anything over 180, then extend the line down. Or buy a 360 degree wheel and a ruler.
Don't think you are going to achive ten minitue accuracy though.

[optical24/7]

P² = H ² +V ² √

P² is the amount of resultant prism
“H” is the horizontal prism amount
“V” is the vertical amount
√ is square

The formula for the prism meridian (axis) is;

Tan ‾¹ = V/H

Example; (Use these keys in their order for 3 up and 5 in)

3÷ 5 = Tan‾¹

Your calculator should say 30.963

Adding 180 degrees depends on if it’s a right or left lens and what direction the principal prism is in.

[Striderswife]

The zero mark is always towards the pt's left ear--that's how I remember it, simple as it is.

[lensgrinder]

Optical 24/7 pretty much covered this, but here is a video.
Go to http://opticaled.com/videos and select any video dealing with prism. The one towards the end Resultant prism by Brent McCardle loads the fastest, but there are some really good ones by Ellen Stoner as well.