Purpose

To define the melanopsin and cone luminance retinogeniculate pathway contributions to photophobia in healthy controls and migraineurs.

Methods

Healthy controls and migraineurs were categorized according to the International Classification of Headache Disorders criteria. Photophobia was measured under full-field illumination using electromyography in response to narrowband lights spanning the melanopsin and cone luminance action spectra. Migraineurs were tested during their interictal headache-free period. Melanopsin-mediated post-illumination pupil responses quantified intrinsically photosensitive Retinal Ganglion Cell (ipRGC) function.

Results

A model combining the melanopsin and cone luminance action spectra best described photophobia thresholds in controls and migraineurs; melanopsin contributions were ∼1.5× greater than cone luminance. In the illumination range causing photophobia, migraineurs had lower photophobia thresholds (∼0.55 log units; p < 0.001) and higher post-illumination pupil response amplitudes (p = 0.03) than controls.

Conclusion

Photophobia is driven by melanopsin and cone luminance inputs to the cortex via the retino-thalamocortical pathway. In migraineurs, lower photophobia thresholds reflect hypersensitivity of ipRGC and cone luminance pathways, with the larger and prolonged post-illumination pupil response amplitude indicative of a supranormal melanopsin response. Our findings inform artificial lighting strategies incorporating luminaires with low melanopsin excitation and photopic luminance to limit the lighting conditions leading to photophobia.

中文翻译：

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黑视素超敏反应在偏头痛发作间期畏光中占主导地位

目的

确定黑色素和视锥亮度视网膜原性通路对健康对照和偏头痛患者的畏光的贡献。

方法

根据国际头痛疾病分类标准对健康对照者和偏头痛者进行分类。畏光是在全视野照明下使用肌电图测量的，以响应跨越黑视蛋白和锥体亮度作用光谱的窄带光。偏头痛患者在发作间期无头痛期间接受了测试。黑视素介导的光照后瞳孔反应量化了内在光敏视网膜神经节细胞 (ipRGC) 的功能。

结果

结合黑视蛋白和锥体亮度作用光谱的模型最好地描述了对照组和偏头痛患者的畏光阈值；黑视蛋白的贡献比锥体亮度高约 1.5 倍。在引起畏光的光照范围内，偏头痛患者的畏光阈值（~0.55 log 单位；p  < 0.001）和光照后瞳孔反应幅度（p  = 0.03）高于对照组。

结论

畏光是由黑色素和锥体亮度通过视网膜 - 丘脑皮质通路输入皮质驱动的。在偏头痛患者中，较低的畏光阈值反映了 ipRGC 和锥体亮度通路的超敏反应，较大和延长的光照后瞳孔反应幅度表明存在超正常的黑视蛋白反应。我们的研究结果为人工照明策略提供了信息，结合具有低黑视蛋白激发和明视亮度的灯具，以限制导致畏光的照明条件。