Personalization can make a big difference in ophthalmic lenses, both single vision and progressive. When a lens is optimized for a single wearer, the best possible optics are achieved. Even two wearers with the same prescription and lens material will receive different lenses comprehensively tailored to their individual biometrics and frame selection. Each wearer will experience the best quality of vision and superior comfort.


Unique Parameters

The personalization parameters used for the compensation calculation are specific to each individual wearer. These parameters represent the unique identity of each wearer and make it possible to create customized lenses.

1. Prescription and Addition

Digital Ray-Path® calculates the power that the user will perceive once the lenses are fitted on the selected frame. The power of the lenses is compensated, so the wearer effectively gets the desired prescribed power when looking through the lens.

2. Naso-pupillary Distance (NPD)

This is the distance from the axis of symmetry of the face (the center of the nose) to the center of the pupil. It is recommended to measure the naso-pupillary distance for each eye separately.

3. Pupil Heights (SEGHT)

This is the vertical distance from the pupil center to the bottom of the frame when the wearer is looking straight ahead. It is recommended to measure it for each eye separately.


4. Frame Sizes

Horizontal Box Size (HBOX), Vertical Box Size (VBOX) and Distance Between Lenses (DBL)

Frame dimensions are used to calculate the final diameter and thickness of the lens. Lens diameter will be selected automatically to obtain the minimum possible thickness. Frame dimensions also improve the efficiency of the optimization, because the final lens is optimized only where it is needed. Finally, pupil heights can be used to automatically select the best corridor length in progressive lenses, in cases where it is not specifically indicated by the ECP.


5. Pantoscopic Angle (PANTO)

This is the angle in the vertical plane between the optical axis of a spectacle lens and the visual axis of the eye in primary position.

6. Wrap Angle (ZTILT)

Frame curvature

7. Back Vertex Distance (BVD)

Distance between the cornea and the back surface of the lens.
Pantoscopic, wrap angle and back vertex distance are used by Digital Ray-Path® to factor in the real position of the lens in front of the eye.


8. Near Working Distance (NWD)

This is the distance from the lens to the reading material, in typical position for the wearer. Near working distance is used to fine tune the Digital Ray-Path® calculation in the near portion of the lens. This parameter will also be used to compute the specific inset value of the progressive design for each individual patient.


Degrees of Personalization

When Digital Ray-Path® lenses are ordered; they can be partially or completely personalized, depending on the information that is available from the wearer. In any case, the advantage over conventional lenses is significant.

Total Personalization

When possible, the ECP should take measurements for all personalization parameters and send them with the lens order for a full compensation. These parameters will be used by Digital Ray-Path® to refine the optimization of the lens. Including these parameters guarantees the best lens for each specific wearer.

Partial personalization

When some of the personalization parameters are not available, the final lens will be personalized using standard values for those parameters that are missing. These standard values have been selected carefully to guarantee a correct optimization for the most common use cases. Standard values shouldn’t be used in cases that require special fitting, like curved frames.
Even if some parameter values are missing, Digital Ray-Path® will still provide superior vision over a conventional lens. The way that prescription, progression, material and base curve are combined on each point of the lens will still be optimized, which accounts for a significant improvement of the lens.