Originally Posted by
harry a saake
:idea: When measuring pd,s, especially for progressives it is not always a good idea to rely on the pupilometer. The pupilometer can be off for two reasons, one being the reflection your seeing is not always the center of the pupil.
.......Second, a pupilometer does not fit on the bridge of the nose the same way the average frame does, even more so with wire frames with adjustable nose pads.
.....Because of the assemetry of the human face and the fact that the human body has a natural curve to the left, you will notice in a good many people the nose curves slighlty to the left also. This is why you will quite commonly notice these differences in pd,s when taken in a monocular fashion. It is typical to see less on the left side of the nose and a slightly higher reading on the right. This is because the nose is slightly more concave on the left and a little more convex on the right.
.....Due to the actual shape of the nose and how the pupilometer sits on it my vary the correct reading, thus it is probably better when fitting progessives and aspheric lenses to also dot the pupil and compare your readings. Of course dotting lenses should always be done after the frame has been fully adjusted in the as worn mode.
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