Cheng Kevin, Martin Laurent F, Calligaro Hugo, Patwardhan Amol, Ibrahim Mohab M
Department of Anesthesiology, College of Medicine, University of Arizona, Tucson, AZ, USA.
Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA.
Clin Med Insights Case Rep. 2022 Sep 20;15:11795476221125164. doi: 10.1177/11795476221125164. eCollection 2022.
Patients with chronic headaches sometimes prefer non-pharmacological methods for pain management. We have shown previously that green light exposure (GLED, Green Light Emitting Diode) reversed thermal hyperalgesia and mechanical allodynia in a rat model of neuropathic pain. This effect is mediated through the visual system. Moreover, we recently showed that GLED was effective in decreasing the severity of headache pain and the number of headache-days per month in migraine patients. The visual system is comprised of image-forming and non-image-forming pathways; however, the contribution of different photosensitive cells to the effect of GLED is not yet known. Here, we report a 66-year-old man with headaches attributed to other disorders of homeostasis and color blindness who was recruited in the GLED study. The subject, diagnosed with protanomaly, cannot differentiate green, yellow, orange, and red colors. After completing the GLED exposure protocol, the subject noted significant decreases in headache pain intensity without reduction in the number of headache-days per month. The subject also reported improvement in the quality of his sleep. These findings suggest that green light therapy mediates the decrease of the headache pain intensity through non-image-forming intrinsically photosensitive retinal ganglion cells. However, the subject did not report a change in the frequency of his headaches, suggesting the involvement of cones in reduction of headache frequency by GLED. This is the first case reported of a colorblind man with chronic headache using GLED to manage his headache pain and may increase our understanding of the contribution of different photosensitive cells in mediating the pain-relieving effects of GLED.
慢性头痛患者有时更喜欢采用非药物方法来管理疼痛。我们之前已经表明，绿光照射（GLED，发光二极管发出的绿光）可逆转神经性疼痛大鼠模型中的热痛觉过敏和机械性异常性疼痛。这种效应是通过视觉系统介导的。此外，我们最近还表明，GLED对减轻偏头痛患者的头痛疼痛严重程度和每月头痛天数有效。视觉系统由成像和非成像通路组成；然而，不同感光细胞对GLED效应的贡献尚不清楚。在此，我们报告了一名66岁的男性，他因体内稳态的其他紊乱和色盲而患有头痛，被纳入了GLED研究。该受试者被诊断为红色弱，无法区分绿色、黄色、橙色和红色。在完成GLED照射方案后，该受试者指出头痛疼痛强度显著降低，但每月头痛天数没有减少。该受试者还报告其睡眠质量有所改善。这些发现表明，绿光疗法通过非成像的内在光敏视网膜神经节细胞介导头痛疼痛强度的降低。然而，该受试者并未报告其头痛频率有变化，这表明视锥细胞参与了GLED降低头痛频率的过程。这是首例报告的使用GLED来管理头痛疼痛的色盲慢性头痛男性病例，可能会增进我们对不同感光细胞在介导GLED止痛效果中所起作用的理解。
