Can someone explain to me the logic behind vertical position of drill holes?
Bridge versus temples.
Why sometimes they are on the same level, and sometimes temples are a bit lower or much lower!?!
Whats the rule?
Can someone explain to me the logic behind vertical position of drill holes?
Bridge versus temples.
Why sometimes they are on the same level, and sometimes temples are a bit lower or much lower!?!
Whats the rule?
I change the vertical drill hole positions often. In the end you want something which looks good and fits well. The other day I had a guy come in with a very large nose. I had to place the bridge 3 mm higher and put the loses a little closer to the inner edge of the lensessthan with the original set-up so that the the guy wasn't looking straight ahead through the lower third of the lens. I left the outer holes at their original vertical position, so I would not have to increase the tilt and unnecessarily stress the hardware. It came out looking very good.
Again, the rule is you want to end up with something which looks good and fits well.
Silhouette's temples are generally 2mm lower than the bridge drill height
B
Kind of depends where you want the top and bottom of lens to ride (nasal drill holes) and one could allow for high or low ears or induce pantoscopic angle with temporal hole locations. There isn't any rule book. You gits to do what ever you think is best.
Chip
The location of drill holes are specified at the whimsey of an industrial designer. Their location is chosen with the single criteria "looks good to me" or "cant see it from my house." Sorry, there are no scientific rules involved.
Silhouettes are made for human faces whereas other manufacturers seem to cater to anomalies, I think they may have some thought behind the process.
From the position of the hole, you should obtain a 5° pantoscopic angle for the face
I forgot there is one rule: The hole location should be the same on each lens. I have received jobs where they were up to 1/4" off.
Angle of the drill hole would give you panto, not the placement.
This rimless frame is a "centerline" design. The temple arms join the frame half-way
between top and bottom of the lens. See how all four screw mounting points are in line?
Enter Ful-Vue Frames
An incredibly hokey magazine spoof of Ful-Vue frames from mid-century.
In the late 1920's, the American Optical Company(AO), the largest manufacturer of eyewear and prescription lenses in the world, filed very, very strong patents on their new "Ful-Vue" design. The Ful-Vue idea was to raise the point where the arms joined the frame, taking them up and out of the way of the wearer's side vision. Remember, this is at the same time many Americans were driving cars for the first time, so they were also using rear view mirrors for the first time. The frames were introduced in 1930.
American Optical was convinced that Americans would be safer wearing Ful-Vue frames, as there would be no temple blocking the wearer's view of the rear view mirror. They also thought that America could be convinced they would be more attractive wearing Ful-Vue styles, with no "line drawn across the face" by the arms.
Ful-Vue Numont
An incredibly hokey magazine spoof of Ful-Vue frames from mid-century.
and lots more at:
http://clearlightoptical.com/Ful-Vue/
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