Optics, Universidad de Granada, Granada, Granada, Spain.
New England College of Optometry, Boston, MA, United States of America.
PeerJ. 2024 May 17;12:e17293. doi: 10.7717/peerj.17293. eCollection 2024.
Aniseikonia is a binocular vision disorder that has been associated with asthenopic symptoms. However, asthenopia has been evaluated with subjective tests that make difficult to determine the level of aniseikonia. This study aims to objectively evaluate the impact of induced aniseikonia at different levels on visual fatigue by measuring the orbicularis oculi muscle activity in the dominant and non-dominant eyes while performing a reading task.
Twenty-four collegiate students (24.00 ± 3.86 years) participated in this study. Participants read a passage for 7 minutes under four degrees of aniseikonia (0%, 3%, 5% and 10%) at 50 cm. Orbicularis oculi muscle activity of the dominant and non-dominant eye was recorded by surface electromyography. In addition, visual discomfort was assessed after each task by completing a questionnaire.
Orbicularis oculi muscle activity increased under induced aniseikonia (, greater values for the 10% condition in comparison to 0%, and 3% conditions ( = 0.034 and = 0.023, respectively)). No statistically significant differences were observed in orbicularis oculi muscle activity for the time on task and between the dominant and non-dominant eyes. Additionally, higher levels of subjective visual discomfort were observed for lower degrees of induced aniseikonia.
Induced aniseikonia increases visual fatigue at high aniseikonia degrees as measured by the orbicularis oculi muscle activity, and at low degrees as measured with subjective questionnaires. These findings may be of relevance to better understand the visual symptomatology of aniseikonia.
复视是一种双眼视觉障碍，与视疲劳症状有关。然而，视疲劳已经通过主观测试进行了评估，这使得难以确定复视的程度。本研究旨在通过测量阅读任务中主导眼和非主导眼的眼轮匝肌活动，客观评估不同水平的诱导复视对视觉疲劳的影响。
24 名大学生（24.00±3.86 岁）参与了这项研究。参与者在 50cm 处，在 0%、3%、5%和 10%四种不同的复视程度下阅读一篇文章 7 分钟。通过表面肌电图记录主导眼和非主导眼的眼轮匝肌活动。此外，在每项任务后通过完成问卷评估视觉不适。
诱导复视时眼轮匝肌活动增加（，10%条件下的值大于 0%和 3%条件（=0.034 和 =0.023，分别））。在任务时间和主导眼与非主导眼之间，眼轮匝肌活动没有观察到统计学上的显著差异。此外，较低程度的诱导复视会导致更高水平的主观视觉不适。
眼轮匝肌活动测量显示，高复视程度的诱导复视会增加视觉疲劳，而主观问卷测量则显示低复视程度也会增加视觉疲劳。这些发现可能有助于更好地理解复视的视觉症状。
