The Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
The Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Exp Eye Res. 2021 Jan;202:108336. doi: 10.1016/j.exer.2020.108336. Epub 2020 Oct 30.
Müller's muscle is a sympathetically innervated smooth muscle which serves as an accessory upper eyelid retractor. Its physiologic function and purpose have not yet been clearly defined. We hypothesize that sympathetic innervation to Müller's muscle serves to adjust the upper eyelid's position to variations in pupil size in response to changes in light intensity.
This is a single center cross-sectional study. Healthy volunteers were asked to fixate on a distant non-accommodative target, and a video scan of the anterior segment was performed for each subject's right eye using the Heidelberg Spectralis® optical coherence tomography scanner in infrared mode. The video was taken both in photopic and scotopic conditions, recording the resultant transition of the pupil and eyelids. The pupil diameter (PD), upper eyelid margin-to-reflex distance (MRD1), lower eyelid margin-to-reflex distance (MRD2), and vertical palpebral fissure height (PFH) were measured.
Thirty-three healthy volunteers (19 women, 57.6%) with a median age of 40 years (range 30-58) were included. The mean PD under photopic conditions increased significantly under scotopic conditions, from 3483 ± 521 μm to 6135 ± 703 μm, respectively (P < 0.0001). An increase in MRD1 was observed following transition from light to dark, with a mean change of 348 ± 311 μm (P < 0.0001). There was no significant change in MRD2.
Upper eyelid retraction occurs after transition from photopic to scotopic conditions. This movement suggests the existence of an "eyelid-light reflex" involving Müller's muscle that adjusts the position of the eyelids as the pupil dilates under scotopic conditions.
Müller 肌是一种交感神经支配的平滑肌，作为辅助上睑提肌。其生理功能和目的尚未明确。我们假设交感神经支配 Müller 肌的功能是调整上睑位置以适应瞳孔大小的变化，以响应光照强度的变化。
这是一项单中心横断面研究。要求健康志愿者注视远处的非调节性目标，然后使用 Heidelberg Spectralis®光学相干断层扫描仪（OCT）以红外模式对每位受试者的右眼进行眼前节视频扫描。在明适应和暗适应两种条件下进行录像，记录瞳孔和眼睑的变化。测量瞳孔直径（PD）、上睑缘至反射距离（MRD1）、下睑缘至反射距离（MRD2）和垂直睑裂高度（PFH）。
共纳入 33 名健康志愿者（19 名女性，57.6%），平均年龄 40 岁（30-58 岁）。在明适应条件下，瞳孔直径平均增加 2652 ± 521 μm，在暗适应条件下增加至 6135 ± 703 μm（P < 0.0001）。从明适应切换到暗适应时，MRD1 增加，平均增加 348 ± 311 μm（P < 0.0001）。MRD2 无明显变化。
从明适应切换到暗适应时，上睑会回缩。这种运动提示存在一种涉及 Müller 肌的“眼睑光反射”，可在暗适应时瞳孔扩张时调整眼睑位置。
