Blended Bifocal with a 40–45 mm Round Ultex segment, focused on a wider near visual field.
Application and design rationale
Greater width in the reading zone
This design features a 40–45 mm Round Ultex segment. The product data lists a 10 mm near reference and nominal 2.5 mm inset.
| Design identifier | Description |
|---|---|
| Category | Blended freeform bifocal |
| Design type | Blended Bifocal |
Technical specifications
Orderable options depend on prescription, material and current product availability.
| Technical parameter | Value / status |
|---|---|
| Product classMarket Segment | Legacy Product |
| Computational technologyCalculation Technology | DuraBase (Nominal Power) |
| Design typeType | Blended Bifocal |
| Available materialsAllowed Materials | All materials |
| Pre-calibrationPrecalibration | Yes |
| PersonalisationPersonalization | No |
| Prism reference pointPrism Reference Point (PRP) | Geometrical centre |
| Distance reference pointDistance Reference Point (DRP) | Equal to PRP |
| Segment shapeSegment Style | Round Ultex |
| Segment widthSegment Width | 40–45 mm |
| Segment vertical dropSegment Vertical Offset | 5 mm |
| Fitting reference pointLayout Reference Point (LRP) | Equal to PRP |
| InsetInset | 2.5 mm |
| Near reference pointNear Reference Point (NRP) | 10 mm |
| Addition rangeAddition Range | +0.50 to +4.00 D |
| PRP decentration range | 0 to 10 mm |
| Specified indices and options | Indices 1.50, 1.53, 1.60, 1.67 and 1.74 In clear, photochromic and polarised options; confirm final availability when ordering. |
| Addition step | 0.25 D |
Design mechanism and features
Two viewing zones with a wide segment
DoubleMax uses a 40–45 mm Round Ultex segment. The distance/near junction has a blended freeform design, distinct from the continuous power transition of a progressive lens.
Production and application
The document describes producing this design from a single-vision blank. It focuses on distance and a wide near field; account for the absence of a progressive corridor when considering sustained intermediate work.
Difference from DualMax
DualMax has a smaller 24–28 mm round segment and 8 mm NRP; DoubleMax specifies 40–45 mm and 10 mm respectively.
Technologies in this design
- DuraBase
- Nominal-power calculations; also described as Nominal Power in the sources.
Measure before manufacture
Required parameters vary by design and must be recorded by a professional.
- Monocular PD
- Each eye's pupillary distance is recorded separately to align horizontal lens positioning with the visual axis.
- Fitting Height
- Fitting height is recorded on the adjusted frame in the natural position of wear; the required near zone must also fit within the frame.
- Box A
- Horizontal width of the frame opening in the boxing system.
- Box B
- Vertical height of the frame opening in the boxing system.
- DBL
- Distance between the two lens boxes at the frame bridge.
- ED
- Effective diameter: twice the greatest distance from the boxing centre to the lens-shape edge, used for blank selection and edging calculations.
Design-specific inputs
- Segment Width: select a reading-field width from 40 to 45 mm according to near-vision needs.
- Inset (near-vision shift): a fixed 2.5 mm inward shift to accommodate natural convergence at reading distance.
Monocular pupillary distance
For aligning the lens centre with each eye's visual axis.
Fitting height
Vertical pupil position relative to the frame in the position of wear.
Back vertex distance
One of the inputs describing the actual position of wear.
These are basic fitting parameters; additional inputs and the level of personalisation are specified for each model.
Complete parameter guide ↖View the original catalogue page
