Purpose: Any of several conditions can cause asthenopia. The purpose of this study was to determine whether the particular sensations or their location vary dependent on the symptom-inducing condition.
Methods: Twenty subjects with good vision performed eight reading tasks in random order during different conditions. Each condition used different stimuli to induce asthenopia. The eight conditions were mixed astigmatism, close viewing distance, upward gaze, dry eyes, lens flipper, small font, glare, and flickering light. Subjects were asked to read until attaining a level of discomfort self-defined as "barely tolerable." After each task, subjects rated the magnitude of several symptom descriptors (burning, ache, strain, irritation, tearing, blurred vision, double vision, dryness, and headache) and their location.
Results: Analysis of variance with repeated measures was used to determine that all of the individual symptom sensation measures (except blur) were significantly related (p values ranged from 0.003 to <0.0001) to the inducing condition. Principal factor analysis with orthogonal varimax rotation was used to test symptom by condition relationships and determined two latent factors, designated external and internal symptom factors (ESF and ISF), that related symptoms to inducing condition. The ESF pattern comprises burning, irritation, tearing, and dryness located in the front and bottom of the eye. ESF is caused by holding the eyelid open, glare, up gaze, small font, and flickering. ESF seems highly related to dry-eye symptoms. The ISF pattern comprises ache, strain, and headache located behind the eyes. ISF is caused by the close viewing distance, lens flipper, and mixed astigmatism conditions and is likely related to accommodative and vergence stress.
Conclusions: Symptom descriptors and locations were able to distinguish discomfort on the basis of causative condition. Results support two different symptom constellations and, hence, at least two different afferent pathways for symptoms of asthenopia.
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I have been coming to Family Vision Center for almost 20 years. Dr. Garbus has been able to help my vision when other doctors could not. Now my kids see him as well. I highly recommend this office!
The Doctor is very good. I felt on this visit he seemed rushed. I had questions to ask him but he was already with another patient. I still do not know if my eyes are the same , worse, or better.
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According to the American Optometric Association, approximately 80% of what a child learns in school is acquired through vision, and vision problems can significantly impact academic performance. As a developmental optometrist, has treated many students who struggle to learn how to read due to vision problems. In this blog, we will explore how vision therapy […]
Bloodshot eyes can be alarming, but they are not always a cause for concern. In this blog, we will discuss the common causes of bloodshot eyes, how to treat them, and when to seek medical attention. We will also provide some helpful tips for preventing bloodshot eyes in the future. Understanding Subconjunctival Hemorrhage A subconjunctival […]
As parents and teachers, we often assume that a child's ability to read the letter chart accurately is the only indicator of good eyesight. However, there is much more to vision than just acuity (identifying the letters on an eye chart). It is critical for parents to understand that a vision screening is only identifying […]
