Is this correct about the cylinder power being like a periscope, 90-degrees from the axis?
The astigmatism dial tool has the axis numbers differently.
Will I measure the axis right using the dial or do I have to convert it (90-degrees faces horizontally in the dial versus up like in the video)? The video above suggests that the axis is not the blurry direction. That means 90-deg cylinder/axis is horizontal astigmatism/blurry vision along the 180-deg line. Do I have this correct, or am I thinking something wrong?
And mainly, can the dial numbers be trusted? Has someone measured their axis wrong by accident? Mine were measured by an optician, so I don’t know where exactly they’re supposed to be pointing. So which of the axis-maps is used in lenses?
(Dumb question really, but I thought there was a fault in the math-page in one of those equations as well, but after watching the youtube video associated with it I realized the fault was that I didn’t understand it but after seeing the picture.)