Experiments conducted on tree shrews, which are relatives of primitive primates, have shown that they develop myopia rapidly if the lighting in their cages lacks the violet part of the solar spectrum.
The Cincinnati Children’s Medical Center (CCHMC) press office notes that, according to American researchers, removing this deficiency prevented vision deterioration.
Professor Richard Lang of the University of Cincinnati says: "Humans evolved to live in open spaces with abundant sunlight. We spend most of our lives indoors and do not receive the full range of wavelengths found in sunlight, which is essential for normal eye development. This leads to myopia, which can, theoretically, be prevented by changing indoor lighting."
Professor Lang and his colleagues have been studying for many years how different photoreceptors in the retinal cells of humans and other mammals participate in the process of focusing vision. Several years ago, they discovered that partial or complete blockage of one of these receptors, neuropsin, leads to the relatively rapid development of myopia in tree shrews (a small group of true mammals that are abundant in the tropical forests of Southeast Asia).
According to the doctors, neuropsin reacts to violet and dark blue-violet light, which is present in sunlight but almost nonexistent in artificial lighting. Based on this idea, the scientists observed how the absence or presence of this radiation, which Professor Lang and his colleagues dubbed "indigo light," affected the eyes of young tree shrews, which are just as susceptible to myopia as humans.
To achieve this, the researchers installed two sets of lights in the tree shrews' cages: one producing standard warm white light, and the other producing blue and violet light with wavelengths between 400 and 468 nanometers. To accelerate the development of myopia, the scientists created special glasses for the tree shrews that distort their vision, thus stimulating elongation of the eyeball.
The results of subsequent experiments showed that indigo light prevented the development of myopia in tree mice, even with the continuous use of glasses, while the visual acuity of the control group rapidly declined to between -10 and -12 diopters after two months of experimentation. This suggests the possibility of similarly protecting children's eyes from developing myopia, something that specialists at Cincinnati Children's Medical Center plan to test in the near future, according to Professor Lang and the scientists.
