Reacción a "A study in mice shows that brain stimulation using contact lenses is effective against depression"

This study proposes a novel line of research for the treatment of depression. Its theoretical basis centers on the retina-brain axis. To date, this axis has been studied from various perspectives. On the one hand, given that the retina is embryologically related to the brain, various studies have examined how alterations in the central nervous system might be reflected in the retina. It has been suggested that the early detection of retinal changes or abnormalities using non-invasive ophthalmological techniques could help detect brain changes before symptoms appear. In other words, from this perspective, the retina would offer a pathway to the brain that would allow for the early detection of certain dysfunctions. Currently, studies have already been published indicating that in some mental disorders there may be thinning of certain nerve layers of the retina, changes in the optic nerve, microvascular alterations, and changes in ganglion cells. However, the study of the significance and extent of these alterations is in its preliminary phase and is not used in routine clinical practice.

On the other hand, light stimulation of the retina has been used for therapeutic purposes, although, as noted in the present study, the mechanism by which this technique acts on the brain differs from that of transcorneal electrical stimulation. In the case of depression, light therapy has been used for years as a therapeutic tool, albeit with limited efficacy. Its effect is based on the stimulation of photosensitive cells connected to other brain structures involved in depression.

Building on this theoretical foundation, this study uses intermittent transcorneal electrical stimulation (TI-TES) as a non-invasive brain stimulation technique that could modulate the functioning of different neural networks altered in depression. This strategy is conceptually interesting and allows for a deeper understanding of the etiopathogenesis of depression, while also exploring new therapeutic avenues for its treatment.

The results of the present study indicate that mice treated with TI-TES showed improvements in mood and behavior, as well as changes in neural function, improved connectivity, reduced inflammation, and increased BDNF (brain-derived neurotrophic factor). All of this suggests that retinal stimulation could produce neuronal effects similar to those of other treatments already in use in routine clinical practice.

Although this study has a solid theoretical foundation and interesting results, its scope is limited to preclinical analysis and, therefore, cannot be extrapolated to routine clinical practice. Nevertheless, this work represents a novel starting point that suggests avenues to explore for treating this condition. Its significance also lies in proposing a minimally invasive approach to treat a condition that, in some cases, responds only partially to current pharmacological approaches, requiring more complex therapeutic strategies such as electroconvulsive therapy or transcranial magnetic stimulation.