The discussion revolves around the concept of astigmatism and its measurement in diopters. Participants explore the meaning of "1 diopter of astigmatism," focusing on the optical principles involved and the implications for lens design.
Participants generally agree on the definition of astigmatism in terms of diopters and the optical principles involved, but there are variations in the descriptions and methods presented.
Some assumptions about the understanding of optical principles and terminology may not be explicitly stated, and there is a lack of consensus on the alternative descriptions provided.
Yes, I do. I know about diopters when I studied optical lenses, and I have also done some research about astigmatism.Ibix said:Do you know what astigmatism is and what a diopter is?
An alternative description is the addition of a cylinder with focal length 1m (as I remember). On my prescription they write 0.4Cyl and the angle.Ibix said:Then it's the difference in optical power along the two principal axes.
Slice the lens through parallel to one axis and make a circularly symmetric (i.e. non-astigmatic) lens with the profile you see. Slice the lens through parallel to the other axis and make another circular lens with this profile. The difference in power of the two circular lenses will be the number of diopters of astigmatism in the original lens.