Table_1_Pupil light reflex dynamics in Parkinson’s disease.DOCX

IntroductionVisual disturbance is common symptom in Parkinson’s disease (PD), and defective pupil light reflex (PLR) is an anticipated contributing factor that may be associated to the presence of autonomic dysfunction, which is a common non-motor feature of PD. Studies investigating the intercorrelation between PLR and dysautonomia in PD are limited.
MethodsThe aim of this study was to investigate differences of PLR parameters, measured by eye-tracker, between patients with PD, with and without signs of dysautonomia, and healthy controls (HC). In total, 43 HC and 50 patients with PD were recruited and PLR parameters were measured with Tobii Pro Spectrum, during a long (1,000 ms) and a short (100 ms) light stimulus. Presence of orthostatic hypotension (OH) was used as proxy marker of dysautonomia. Linear mixed-effects model and non-parametric comparative statistics were applied to investigate differences among groups.
ResultsPeak constriction velocity was slower in PD compared with HC, after adjustment for age and sex in the mixed model, and the difference was greater in the subgroup of PD with OH (unadjusted). Dilation amplitude and velocity were also gradually slower in HC vs. PD without OH vs. PD with OH (unadjusted for confounders). In the mixed model, age was significant predictor of dilation response.
DiscussionOur results support previous observations on defective PLR in PD, evaluated with eye-tracker, and show a possible association with autonomic dysfunction. Further studies with more patients and rigorous evaluation of autonomic dysfunction are needed to validate these findings.

引言
视觉障碍是帕金森病（Parkinson’s Disease, PD）的常见临床症状，而异常的瞳孔光反射（pupil light reflex, PLR）被认为是潜在致病因素之一，其可能与自主神经功能障碍相关——而自主神经功能障碍是PD常见的非运动特征。目前针对PD患者PLR与自主神经功能异常之间相关性的研究较为有限。

方法
本研究旨在通过眼动追踪（eye-tracker）技术，对比存在/无自主神经功能异常征象的PD患者与健康对照（healthy controls, HC）之间的PLR参数差异。本研究共招募43名健康对照与50名PD患者，采用Tobii Pro Spectrum眼动仪，分别在长时（1000ms）与短时（100ms）光刺激条件下测量PLR参数。本研究以体位性低血压（orthostatic hypotension, OH）作为自主神经功能异常的替代标志物。采用线性混合效应模型与非参数比较统计学方法，分析各组间的参数差异。

结果
在校正年龄与性别后的线性混合模型分析中，PD患者的瞳孔收缩峰值速度慢于健康对照；且在未校正混杂因素的分析中，合并OH的PD亚组差异更为显著。健康对照、无OH的PD患者、合并OH的PD患者的瞳孔扩张幅度与速度依次减慢（未校正混杂因素）。在线性混合模型中，年龄是瞳孔扩张反应的显著预测因子。

讨论
本研究结果验证了此前通过眼动追踪技术发现的PD患者PLR异常的结论，并提示PLR异常可能与自主神经功能障碍相关。未来需纳入更多受试者并对自主神经功能进行严格评估，以验证本研究的发现。