Andrew S. Bruce, LDO, ABOM, NCLEM, FCLSA, FNAO: No relevant disclosure to display
Brought to you by the National Academy of Opticianry and SECO International.
This program will begin with a basic introduction to prism. The distinction between prescribed prism and induced prism (good vs. bad), will be presented, leading to Prentice’s rule. Common effects of induced prism with also be presented, prior to the main topic of discussion – prismatic imbalance. A step-by-step guide for calculating vertical imbalance at the near point will then be provided; methods to compensate for vertical imbalance will be discussed; specifically, slab off.
Learning Objectives:
Upon conclusion of this activity, attendees will be able to:
Understand the basics of prism and how it relates to basic lens construction
Communicate the difference between good prism vs. bad, and demonstrate the use of Prentice’s rule
Discuss prismatic imbalance and calculate vertical imbalance
Calculate meridional lens power
Examine different techniques used to compensate for vertical imbalance, at the near point, with a multifocal lens
Consider, calculate, and manage vertical imbalance at both distance and near in a progressive addition lens
