lenses and frames

MDA – Greater width of the rim or diagonal -Obtained by scanning with the rulerPA – Bridge+Rim - as always in the height where position the optical centers.

A – width rimB – lens heightDEL – Distance between lenses

The virtual rectangle that contains the rim determines the dimensions of the frame.

• Influence in the analysis frame, as measurements are marked on the stem width "bridge" refers shaft length where the proposed new "bridge" is in fact the distance between the lenses.

• This can influence particularly in automatic assembly where assemblers use the bridge information to fitting rimless and semi rimless glasses.

The end of one lens to the other one.

“BRIGDE+RIM”

“BRIGDE+RIM”

Distance between centers of the rims

DPPupillar Distance

Influence of the Bridge+Rim measured and rim size on plus lens thickness.

Influence of the Bridge+Rim measured and rim size on plus lens thickness.

Minus lenses

TECHNICAL FRAMES

Same lens mounted on frames with different “Bridge+Rim”

Big Frames

Big Frames

Big Frames

dm – Fitting decentralizationda – Height decentralization

𝑑𝑚 =𝑃𝐴 −𝐷𝑃

2=

𝑃𝐴

2− 𝐷𝑁𝑃

∅ = 𝑀𝐷𝐴 + 2 × 𝑑𝑎 𝑜𝑢 𝑑𝑚

Whichever is greater𝑑𝑎 = 𝑓𝑖𝑡𝑡𝑖𝑛𝑔 ℎ𝑒𝑖𝑔ℎ𝑡 −

𝑟𝑖𝑚 ℎ𝑒𝑖𝑔ℎ𝑡

2

Fast way to determine diameter

- 30,00 dioptrias +20,00 dioptrias

“Blending” Edge

This type work performed in the left minus lenses was called "visodrop" or "myodisc" is an alternative to strong diopters.

THANKS

THANKS