Major depressive disorder (MDD) affects people worldwide. MDD treatments include antidepressants, which involve a delayed onset of action, long-term treatment, side effects and, frequently, only partial efficacy. The lack of access to the living brain, and the complex and still poorly elucidated pathophysiology of MDD, hinders treatment development. There is not only a need for new treatment strategies, but also for new approaches to investigating the pathophysiology of MDD. Light therapy is a well-established treatment acting through the retina. Since the retina is part of the central nervous system, it has been suggested as a useful area for investigating mental illness. In this article, we will first set out the evidence that MDD affects the retina's structure and function. We will then review studies evaluating the efficacy of light therapy in unipolar non-seasonal MDD. Finally, we discuss the disruption of melatoninergic pathways in MDD, its assessment through the retina and the treatment of this disruption with light therapy.

中文翻译：

---

视网膜在重大抑郁症诊断和治疗策略中的作用的新见解。

严重抑郁症（MDD）影响全世界的人们。MDD治疗包括抗抑郁药，其作用延迟，长期治疗，副作用以及通常仅部分疗效。缺乏接触活脑的机会，以及MDD的病理生理机制复杂且仍难以阐明，阻碍了治疗的发展。不仅需要新的治疗策略，而且需要研究MDD病理生理的新方法。光疗法是通过视网膜起作用的公认疗法。由于视网膜是中枢神经系统的一部分，因此建议将其作为研究精神疾病的有用区域。在本文中，我们将首先提出MDD影响视网膜结构和功能的证据。然后，我们将回顾评估光疗法在单极非季节性MDD中的疗效的研究。最后，我们讨论了MDD中黑色素能途径的破坏，其通过视网膜的评估以及光疗法对这种破坏的治疗。