The contact lens that knows light

Light is both essential for sight, and yet can be challenging for the visual system to cope with. In a recent review, Hammond et al (2019) highlighted the wide range of visual intensities humans are exposed to over the course of an average day; the impact light has on visual performance, and how spectral filtering has been shown to improve functional vision in a number of situations relatable to real-world experience.⁶

It has become increasingly apparent that a significant proportion of patients have problems coping with bright light. Nearly two-thirds (64%) admit to being bothered by harsh or bright lighting conditions on a daily basis.¹ This is not an insignificant issue. The coping mechanisms adopted when light becomes troublesome include shading or averting the eyes, turning down the brightness of digital devices and turning off room lights (figure 1).¹ Actions which are certainly inconvenient, and for some behaviours such as squinting, have the potential to cause visual discomfort and fatigue.^{7 8}