One area of Opticianry that seems to have more Opticians baffled is prism. I hope in this short tutorial to ease the misunderstanding of prism. This tutorial is not meant to understand every aspect of prism, it is meant to help you understand prism in your everyday setting as an Optician.
In order [...]

When we compensate an Rx, we do so because the lens changes power as moves closer or farther away from the eye. We are making an Rx stronger or weaker depending on whether the lens is moved closer farther away

1. The approximate power on the vertical meridian for the Rx +3.00 -1.50 x 102 is ______. Give the power rounded to two decimal places, not to 1/8 diopter steps.
Vertical meridian is the power in the 90th meridian. First we need to subtract our axis(102 in this problem) from the meridian we are [...]

1. If a polycarbonate lens (n = 1.586) is made with a front surface power of +10.25, a back surface power of -3.00, and a center thickness of 4 mm, what power will the lensmeter show? Give the power rounded to two decimal places, not to 1/8 diopter steps.

Determining the correct lens blank is the first step to surfacing a lens. This is a two step process, the fist step is to find the correct base curve and the second step is to determine the needed blank size.

The purpose of this article is to build on what was discussed inRay Tracing of Thin Lenses. If you have not read that article it would be wise to do so. This article assumes a basic understanding of mathematical concepts and an understanding of some optics.

The purpose of this article is to help those to understand how lenses
work through the understanding of ray tracing. For the purpose of this
discussion we are only going to deal with thin lenses.