Lei Shaobo, Goltz Herbert C, Chen Xingqiao, Zivcevska Marija, Wong Agnes M F
Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada.
Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada 2Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada 3The Krembil Research Institute, Toronto Western Hospital, Toronto, Ontario, Canada.
Invest Ophthalmol Vis Sci. 2017 Mar 1;58(3):1449-1454. doi: 10.1167/iovs.16-21285.
To investigate the chromatic characteristics and intensity-response function of light-induced reflex lacrimation and its correlation with the melanopsin-driven postillumination pupil response (PIPR).
Eleven visually normal participants completed the experiment. Lacrimation was measured in one eye by placing a calibrated filter paper strip in the conjunctival sac over a 1 minute-interval (Schirmer's test) during which participants received either no light stimulation (baseline trial) or one flash of blue or red light stimuli presented binocularly with a Ganzfeld stimulator, while the pupil response was recorded simultaneously from the fellow eye by using an eye tracker. Light stimulation trials were presented in alternating fashion at seven incremental intensity steps (0.1, 1, 3.16, 10, 31.6, 100, and 400 cd/m2). Postillumination pupil response was defined as the mean pupil constriction from 10 to 30 seconds post illumination.
The amount of lacrimation in response to 10 to 400 cd/m2 blue light was significantly greater than baseline and increased monotonically with increasing light intensity. Red light did not induce significant reflex lacrimation until the brightest stimulation at 400 cd/m2. There was a positive linear correlation between PIPR and lacrimation in response to blue light (r = 0.74, P < 0.001) but not to red light (r = 0.13, P = 0.25).
The chromatic characteristics and intensity-response of light-induced lacrimation are highly consistent with the features of melanopsin phototransduction. This finding is the first in vivo evidence in humans, supporting the hypothesis that light-induced reflex lacrimation is mediated primarily by melanopsin photoactivity, and provides new insight into the putative mechanisms of photophobia.
研究光诱导反射性流泪的颜色特征和强度反应函数及其与黑视蛋白驱动的光照后瞳孔反应（PIPR）的相关性。
11名视力正常的参与者完成了该实验。通过将校准的滤纸条放置在结膜囊中1分钟（Schirmer试验）来测量一只眼睛的流泪情况，在此期间参与者要么不接受光刺激（基线试验），要么通过Ganzfeld刺激器双眼接受一次蓝光或红光刺激，同时使用眼动仪从另一只眼睛记录瞳孔反应。光刺激试验以交替方式在七个递增强度步骤（0.1、1、3.16、10、31.6、100和400 cd/m²）下进行。光照后瞳孔反应定义为光照后10至30秒的平均瞳孔收缩。
对10至400 cd/m²蓝光的流泪量显著大于基线，并随光强度增加而单调增加。直到400 cd/m²的最亮刺激，红光才引起显著的反射性流泪。蓝光刺激下的PIPR与流泪之间存在正线性相关（r = 0.74，P < 0.001），而红光刺激下则无相关性（r = 0.13，P = 0.25）。
光诱导流泪的颜色特征和强度反应与黑视蛋白光转导的特征高度一致。这一发现是人类体内的首个证据，支持了光诱导反射性流泪主要由黑视蛋白光活性介导的假设，并为畏光的推定机制提供了新的见解。
