Prismatic Effect Calculation

Assalamualaikum and Very Afternoon to all readers,

For 2nd year students, do you still remember the rule how to determine Prismatic Effect (base up, down, in out) that I've been taught in class last week. InsyaAllah, I'll share it the rule using video post with all of the readers in next time.

How to calculate the prismatic effect amount induced by decentration??? The formula is very simple.

P (prism power)=c (decentration, in cm, not in mm) x F (focal power, D)

Simple, right...most of us have difficulty to determine which base will be induced by the decentration (c- in, out, up, down) and focal power (F- plus, minus)...by using my rule, InsyaAllah it will be easier to determine it. As I said before, the video is under construction but I've explain it in 2nd year class..Thus, in this post I would to give a tutorial to all 2nd year regarding this topic.

Question: Calculate prismatic effect if the decentration and focal power as follow; 

Hoya's Lens Material Pop Quiz

Assalamualaikum and Good Evening,

Hi to readers, let's relax your mind by answering Hoya's Lens Material Pop Quiz at the side corner of this blog..Just click at the answers given...No mark...refresh our product knowledge..The correct answer will be given on this Thursday.

Have a fun! Happy weekend..

Movement of Retinosope Reflex

There are two ways to explain how does movement of retinoscope reflex happens. 1) aerial image-blurred image orientation/ position on retinoscopist's retina, 2) Secondary Source-Far point location , MR. Always remember 1) the aerial image will be located either in front of or at  behind examiner's eye, and 2) the Far point, MR will be located either in front of or at  behind patient's eye.