Nahar Niru K, Gowrisankaran Sowjanya, Hayes John R, Sheedy James E
The Ohio State University, College of Optometry, Columbus, USA.
Optometry. 2011 Nov;82(11):689-96. doi: 10.1016/j.optm.2011.07.003. Epub 2011 Aug 31.
The objective of this research is to assess the ocular and muscular response to long-duration reading under different visual and cognitive difficulty levels.
Thirty-five subjects, with 20/20 vision and without history of ocular pathology or cognitive deficits, participated in the study. Subjects read under different visual and cognitive difficulty levels for 6 (30-minute) conditions. Upper and lower orbicularis oculi, frontalis, and trapezius muscle activities were recorded using surface electromyography (EMG). Aperture size, pupil diameter, and pulse rate of the subjects were recorded with a video camera, pulse meter, and ISCAN eye tracker (ISCAN Inc.), respectively.
The results show that the texts read with a refractive error caused increased orbicularis oculi EMG power and reduced aperture size (P < 0.001). There was no statistically significant difference between the conditions for pulse rate, pupil diameter, or EMG activity of the frontalis and trapezius muscles with either visual or cognitive stress presented in this experiment.
Visual stress experienced due to reading under an induced refractive error is potentially mediated by a local mechanism, different from the mechanism underlying reading under low contrast or high cognitive demand.
本研究的目的是评估在不同视觉和认知难度水平下长时间阅读时的眼部和肌肉反应。
35名视力为20/20且无眼部疾病或认知缺陷病史的受试者参与了该研究。受试者在不同视觉和认知难度水平下阅读6种（30分钟）条件。使用表面肌电图（EMG）记录眼轮匝肌上、下部、额肌和斜方肌的活动。分别用摄像机、脉搏计和ISCAN眼动仪（ISCAN公司）记录受试者的孔径大小、瞳孔直径和脉搏率。
结果表明，在存在屈光不正的情况下阅读文本会导致眼轮匝肌EMG功率增加和孔径减小（P<0.001）。在本实验中，无论是视觉应激还是认知应激，额肌和斜方肌的脉搏率、瞳孔直径或EMG活动在各条件之间均无统计学显著差异。
在诱导屈光不正情况下阅读所经历的视觉应激可能由一种局部机制介导，这与低对比度或高认知需求下阅读的潜在机制不同。
