Suitability of blue light filters for eye care

Light entering through the eyes is responsible for the regulation of circadian cycles. The blue range of the visible spectrum is primarily responsible for the action of melanopsin, whose peak sensitivity is around 480 nm. Many intraocular and prescription lenses for correcting ametropia have a filter with increasing absorptivity below 475 nm until it completely cuts off light below 420 nm, under the argument that violet and near blue are harmful. Therefore, the wearers receive little light in that range. The use of these filters is based on studies claiming that that range can damage the retina or disturb sleep when using electronic devices in the evening/night. However, this work shows that blue light emitted by electronic devices is lower than that received from indoor or natural light. Recent publications claim that the cause of the current pandemic of childhood myopia may be due to insufficient natural light or even a lack of violet light during eye development. On the other hand, older people require more light due to yellowing of the transparent media of the eye. The authors of this work consider that filters cannot be used indiscriminately to limit part of the visible light whose percentage in the regulation of circadian cycles is not fully characterized. Further studies should be carried out to quantify accurately the possible damage of this part of visible light on the retina. We believe that each patient should be analyzed before using filters that block higher-frequency visible light.