Acosta M C, Gallar J, Belmonte C
Instituto de Neurociencias, Universidad Miguel Hernández, San Juan de Alicante, 03550, Spain.
Exp Eye Res. 1999 Jun;68(6):663-9. doi: 10.1006/exer.1998.0656.
The aim of this work was to study blink frequency changes and levels of ocular discomfort during work at a video display terminal, and the effects on these parameters of augmented or reduced humidification of the ocular surface. Blink rate was measured from recordings of the electrical signal evoked by the contraction of the orbicularis oculi muscle. Blink rate and interblink intervals were analyzed at rest and during performance of a task with a computer (playing a card game) for 10 or 30 min in steady environmental conditions and during application of a continuous stream of air to the face. In two separate sessions, the effect of pretreatment with humidifying ocular solutions of different elastoviscosity (balanced salt solution or elastoviscous 0.1% Hylan A solution) was assayed. At the end of each experimental period, the subjects marked the level of ocular discomfort experienced on a 0-10 cm visual analogue scale. The blink frequency at rest (12.4+/-1.2 blinks min-1) was reduced significantly (to 10.3+/-1.1 blinks min-1) by pretreatment with elastoviscous eyedrops both with and without air applied to the face. This effect was not obtained with balanced salt solution. During performance of the visual task for 10 or 30 min, basal blink rate decreased significantly, to about 40% of the control value. Neither application of an air jet on the face nor application of eye solutions of different viscosity modified this reduced blink rate.A low degree of ocular discomfort developed after performance of the visual task that was enhanced by air application to the face. This discomfort was reduced by pretreatment with ocular solutions, the elastoviscous eye solution being more efficient than the balanced salt solution. Interblink interval duration was also more regular after treatment with the elastoviscous solution. These data suggest that blink rate at rest is maintained in part by activation of sensory receptors of the cornea and conjunctiva, which are stimulated by desiccation of the ocular surface. Reduction of eye blink frequency elicited by the performance of a visual task with a computer appears to depend on central neural mechanisms that are quite independent of peripheral sensory inputs. The reduction of blink frequency consecutive to computer use was associated with a sensation of discomfort that was attenuated more effectively by elastoviscous eyedrops than by regular balanced salt solution.
这项工作的目的是研究在视频显示终端工作期间的眨眼频率变化和眼部不适程度，以及眼表加湿增加或减少对这些参数的影响。通过记录眼轮匝肌收缩诱发的电信号来测量眨眼率。在稳定的环境条件下，以及在向面部持续吹气时，分别在休息时和进行10或30分钟的计算机任务（玩纸牌游戏）期间分析眨眼率和眨眼间隔。在两个独立的实验环节中，测定了用不同弹性粘度的眼部加湿溶液（平衡盐溶液或0.1%弹性粘性透明质烷A溶液）预处理的效果。在每个实验阶段结束时，受试者在0 - 10厘米视觉模拟量表上标记所经历的眼部不适程度。无论是否向面部吹气，用弹性粘性眼药水预处理均能使静息时的眨眼频率（12.4±1.2次/分钟）显著降低（至10.3±1.1次/分钟）。平衡盐溶液未产生此效果。在进行10或30分钟的视觉任务期间，基础眨眼率显著下降，降至对照值的约40%。向面部吹气或使用不同粘度的眼药水均未改变这种降低的眨眼率。视觉任务完成后会出现轻度眼部不适，向面部吹气会加重这种不适。眼部溶液预处理可减轻这种不适，弹性粘性眼药水比平衡盐溶液更有效。用弹性粘性溶液处理后，眨眼间隔持续时间也更规律。这些数据表明，静息时的眨眼率部分由角膜和结膜的感觉受体激活维持，这些受体受眼表干燥刺激。进行计算机视觉任务引起的眨眼频率降低似乎取决于与外周感觉输入相当独立的中枢神经机制。连续使用计算机导致的眨眼频率降低与不适感相关，弹性粘性眼药水比常规平衡盐溶液更有效地减轻了这种不适感。
