Eliminating vertial and horizontal DPE

**Whitwoo** · 11-02-2008, 03:38 PM

Hey guys

.. yes, me again!

Calculate the changes required to the segment specifications to eliminate all vertical and horizontal DPE at the NVP (near visual point) in the following:

R +1.25 / -0.25 x 180

L +3.50 / -0.50 x 180

add +2.50D segs 22 x 2 x 3 mm in

NVP 10mm down, 3mm in

THANKS!

**rolandclaur** · 11-03-2008, 02:04 AM

Dumb question but what is dpe? something power error right?

**HarryChiling** · 11-03-2008, 01:22 PM

Originally Posted by rolandclaur

Dumb question but what is dpe? something power error right?

It's the Differential Prismatic Effect, American opticians refer to it as prism imbalance. page 48 and 49 Mo Jalie, Ophthalmic Lenses and Dispensing, it will give you the formuals you need as well as the definition. E-mail me for more details if you like.