Signs and Symptoms
The signs of visual stress are things that you might observe in a student, client, patient or family member. Individuals may not realize they are doing these things when asked or may believe that the discomfort or distortions they experience are normal and experienced by everyone so will not readily report them. When investigating for visual stress, observation is an important part of diagnosing the condition.
Common signs include:
Wearing brimmed hats or sunglasses inside
Turning off or dim the lights inside and keep the blinds closed
Sitting in dark places to read, study or work.
Dimming computer screens and avoid working on them for extended periods.
Difficulty reading without using a finger
Difficulty writing neatly and well-spaced
Skipping words or lines when reading aloud
Appearing very uncomfortable when reading or doing homework: squint, rub eyes, angle their head to read, constantly change position, or shake their head like they are trying clear it.
Easily distracted by the smallest things
Frustrated, fidgety and restless when reading or doing homework
Trouble with their vision prescriptions even if they are adjusted
Not tolerating UV, blue blocker, or antireflective coatings on glasses (these are filters)
While these could be signs that visual stress is present, it is important to investigate other possible causes. In their book Vision and Reading Difficulties, Dr’s Wilkins, Evans and Allen cautioned people to make assumptions that it is visual stress because there are many factors to consider. It could be an undiagnosed refractive error, a problem with binocular vision, or a perceptual problem (visual stress). It could also be a combination of all three, and thus all three should be corrected.
No matter the apparent cause of the problem, anyone who has difficulty reading should have a full vision investigation by an eye care professional who specializes in vision and learning. This assessment can occur in conjunction with a visual stress assessment as visual stress may still be present even after vision correction.
In 2017, a Delphi study was conducted to improve the diagnostic criteria for visual stress. Published in the Journal of Optometry, the study identified practical guidelines for diagnosing the condition (Evans, Allen, Wilkins J Optom. 2017 Jul - Sep;10(3):161-168. doi: 10.1016/j.optom.2016.08.002. Epub 2016 Nov 24).
As part of our assessments at Opticalm, we evaluate our clients’ perceptual distortions. After describing what they experience when viewing text and patterned images, we use a set of illustrated distortions to help them to further describe what they perceive. Many clients are surprised we have images illustrating what they personally experience, especially since, until now, no one believed them. These images are very useful in helping people convey to their teachers, employers and families, their challenges and the importance of accommodating for them.
Over the past 35 years, multiple research papers have consistently reported the following perceptual distortions: intermittent blurring; duplication; jumping; switching; and fading of the visual image.
Static Sample Distortions
Below are static sample distortions that people commonly report. You can also see the animated version of these and other images.
Animated sample distortions are not available on our mobile website.
WARNING: These images can cause discomfort and trigger seizures in patients with photosensitive epilepsy.