Precal

Optomised thickness for all lenses

Precal is a lens calculation process which pre-determines the thickness of a glazed lens, based on lens and frame shape, prescription and centration. Precal calculates the minimum centre thickness to which a lens can be surfaced to provide the thickness appropriate to the lens/mount combination. The Precal calculation will only be applied asked for by the customer.


Parameters required for Precal

PROVIDE FULL PRESCRIPTION

  • Lens Type
  • Prescription RE & LE
  • Coatings/Tints
  • Frame Type

SAMPLE 1

Rx
SPH
CYL
AXIS
PRIMS
ADD
O.D
+3.00
-0.50
010
+2.25
O.S
+3.00
+2.25

SAMPLE 2

Rx
SPH
CYL
X
AXIS
PRIMS
ADD
O.D
+3.00
-0.50
010
+2.25
O.S
+3.00
+2.25

SAMPLE 3

Rx
SPH
CYL
AXIS
PRIMS
DISTANCE
O.D
+3.00
-0.50
010
O.S
+3.00
NEAR
O.D
+5.25
O.S
+5.25
-0.50
010

Frame details
  • precal_imgFrame A measurement.
  • Frame B measurement.
  • DBL – the frame D measurement.

Dispensing-Details-Easy-to-FitPupillary distance and height
  • Monocular P.D measurement.
  • Frame height for both RE and LE

Frame shape outline

Provide the outline of the selected frame OR Choose from one of the standard 8 precal shapes which is closest to the selected frame shape.