Neurodegenerative diseases share retinal abnormalities. Chromatic pupillometry allows assessment of photoreceptor functional integrity, including melanopsin-expressing retinal ganglion cells. This exploratory meta-analysis assesses retinal photoreceptor functionality in Alzheimer's vs. Parkinson's disease and conducts an in-depth review of applied pupillometric protocols. Literature reviews on PubMed and Scopus from 1991 to August 2023 identified chromatic pupillometry studies on Alzheimer's disease (AD; n = 42 patients from 2 studies) and Parkinson's disease (PD; n = 66 from 3 studies). Additionally, a pre-AD study (n = 10) and an isolated REM Sleep Behavior Disorder study (iRBD; n = 10) were found, but their results were not included in the meta-analysis statistics. Melanopsin-mediated post-illumination pupil response to blue light was not significantly impaired in Alzheimer's (weighted mean difference = −1.54, 95% CI: 4.57 to 1.49, z = −1.00, p = 0.319) but was in Parkinson's (weighted mean difference = −9.14, 95% CI: 14.19 to −4.08, z = −3.54, p < 0.001). Other pupil light reflex metrics showed no significant differences compared to controls. Studies adhered to international standards of pupillometry with moderate to low bias. All studies used full-field stimulation. Alzheimer's studies used direct while Parkinson's studies used consensual measurement. Notably, studies did not control for circadian timing and Parkinson's patients were on dopaminergic treatment. Results affirm chromatic pupillometry as a useful method to assess melanopsin-related retinal cell dysfunction in Parkinson's but not in Alzheimer's disease. While adhering to international standards, future studies may analyze the effects of local field stimulation, dopaminergic treatment, and longitudinal design to elucidate melanopsin dysfunction in Parkinson's disease.

中文翻译：

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黑视蛋白视网膜神经节细胞在阿尔茨海默病与帕金森病中的功能探索性荟萃分析和瞳孔测量方案回顾

神经退行性疾病都有视网膜异常。彩色瞳孔测量可以评估感光器功能完整性，包括表达黑视蛋白的视网膜神经节细胞。这项探索性荟萃分析评估了阿尔茨海默病与帕金森病的视网膜感光功能，并对所应用的瞳孔测量方案进行了深入审查。1991 年至 2023 年 8 月 PubMed 和 Scopus 上的文献综述确定了关于阿尔茨海默病（AD；n = 42 名患者，来自 2 项研究）和帕金森病（PD；n = 66 名，来自 3 项研究）的彩色瞳孔测量研究。此外，还发现了一项 AD 前研究 (n = 10) 和一项孤立的 REM 睡眠行为障碍研究 (iRBD；n = 10)，但其结果未包含在荟萃分析统计中。黑视蛋白介导的光照后瞳孔对蓝光的反应在阿尔茨海默病中没有显着受损（加权平均差 = -1.54，95% CI：4.57 至 1.49，z = -1.00，p = 0.319），但在帕金森病中却受到显着损害（加权平均差 = -1.54，95% CI：4.57 至 1.49，z = -1.00，p = 0.319 = -9.14，95% CI：14.19 至 -4.08，z = -3.54，p < 0.001）。其他瞳孔光反射指标与对照组相比没有显着差异。研究遵循瞳孔测量的国际标准，具有中度至低度偏差。所有研究都使用全场刺激。阿尔茨海默氏症的研究使用直接测量，而帕金森氏症的研究则使用双方同意的测量。值得注意的是，研究没有控制昼夜节律时间，并且帕金森病患者正在接受多巴胺能治疗。结果证实，彩色瞳孔测量是评估帕金森病患者黑视蛋白相关视网膜细胞功能障碍的有用方法，但不适用于阿尔茨海默病患者。在遵守国际标准的同时，未来的研究可能会分析局部场刺激、多巴胺能治疗和纵向设计的效果，以阐明帕金森病中的黑视蛋白功能障碍。