Re: [ATM] Sphereometer accuracy

[Dominic-Luc Webb <dlwebb@canit.se>]

>>The only one I have seen seemed to have similar precision as
>>the spherometers we are more familiar with. I would appreciate
>>if someone here can tell me what this device might be called
>>and what precision is typical.

> The ones with which I am familiar were called profilometers, 
> and were not specific to opthalmics.
> Precisions on the order of ten millimicrometers are 
> attainable, and accuracies better than 100 millimicrometers 
> are not uncommon, 
> depending on the basic curvature and finish of the surface.
> 
> Fascinating devices!
> 
> Stan Truitt

Wow! I did not have any idea they were this accurate. I have 
been thinking to build one using some kind of digital 
micrometer, passing the electronic readout to a computer. This 
would be convenient for determining wedges, bulges, etc on 
transmitted optics in which symmetry between the two sides is 
required. It seems that "profilometers" are maybe what some of 
us should be building. I just googled this and found some 
fascinating stuff. Take a look at the images search.

Dominic-Luc Webb
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