The wearer’s near vision behaviour (NVB) ratio, describes how the wearer adjusts his or her gaze vertically during near tasks.
That ratio is close to 0 for wearers who have a strong tendency to lower their eyes whenever they move to the next line, and therefore change their head and body posture or the tablet position only slightly; the ratio is close to 1 when wearers maintain a static gaze position, i.e., they have a strong tendency to change their posture and/or their position of their digital device or reading material.
Thanks to large wearer studies each wearer’s behaviour is reproducible and represents an appropriate data point for customization, since it is both specific to each individual and differentiating.
Near Vision Behaviour (NVB) personalisation aims to ensure lenses are designed and tailored as closely as possible to the wearer’s specific posture and behavior during near vision work.
Vertical and horizontal variations in power can be controlled to maximize field depth and expand the field of vision, minimising aberrations and maximising visual acuity.
Why would you want to? Lightweight tailor made options exist.
The Varilux progressive lens was first introduced by Bernard Maitenaz in 1959,enabling clear distance vision on upgaze versus reading vision and in between on downgaze.
