Many neurological conditions have symptoms that overlap and it may be difficult to distinguish between the symptoms and the root causes. Visual stress shares many symptoms with these conditions. Because it is often overlooked as a contributing factor, some individuals are not getting the symptom relief they could be receiving.
This section outlines the various conditions that share symptoms with visual stress and explains why it may be prudent to investigate for visual stress and if present, recommend precision tinted filters and other related assistive tools and technologies to help manage and relieve symptoms.
Once addressed, while symptoms of the related conditions will remain, they will be easier to identify and manage with strategies specific to the condition itself.
Note that when visual difficulties are reported, a full optometric evaluation is required to identify, treat or rule out issues of eye health, refraction correction or neuro-optometric problems prior to coming in for a visual stress assessment. While neuro optometric difficulties and visual stress are independent conditions, they often occur together and can be accommodated with combined treatments.
ADHD - Anxiety - Autism - Dyslexia - Epilepsy - Hallucinations - Mal de Debarquement - Migraine - Multiple Sclerosis -
Myalgic Encephalomyelitis / Chronic Fatigue - Post Brain Injury / Concussion Syndrome - Post Traumatic Stress Disorder -
Specific Learning Disabilities - Stroke - Tourettes Syndrome - Vestibular Disorders / Motion Sickness - Visual Snow
ATTENTION DEFICIT HYPERACTIVITY DISORDER (ADHD)
ADHD is characterized by symptoms of inattention, hyperactivity, and impulsivity and is thought to be caused by dysfunctional brain activity and stimulus processing. Visual stress is characterized by many sensitivities and symptoms that cause distraction and make it difficult to concentrate and stay on task, specifically reading and writing. It is caused by difficulties in processing visual stimuli and leads to brain hyperactivity. This strong degree of overlap in symptoms would indicate the importance of ruling out and treating visual stress if it is contributing to symptoms.
Many factors often cause anxiety in the classroom, the workplace or in public. Understanding what visual stress is and how it manifests, may help identify the origin of some triggers to the anxiety. Visual stress symptoms include headaches, disequilibrium, illusions of movement, and distortions in objects that are caused by a sensitivity to light, glare, flicker, colour, motion or patterns. These visual images are ever present in our visual environment so being amongst them can become overwhelming and uncomfortable, leading to anxiety for individuals with visual stress.
AUTISM SPECTRUM DISORDER (ASD)
ASD affects a person’s social interaction, communications, interests and behaviour. Neuronal hyperactivity and painful perception of environmental stimuli are also reported. Visual stress is caused by hyperactivation of the visual cortex and key symptoms are physical discomfort (photosensitivity, headache) and perceptual distortions from exposure to certain visual stimuli in the environment. Many symptoms reported in both conditions overlap, thus it would be prudent to rule out and treat visual stress if present and contributing to symptoms.
Dyslexia is a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling with characteristic difficulties with phonological awareness, verbal memory and verbal processing speed. Motor co-ordination or sensory difficulties such as visual stress can occur alongside dyslexia.  While visual stress may contribute to the overall challenges that a dyslexic individual experience it is unlikely to be a cause of dyslexia  but a higher prevalence of visual stress is found in individuals with dyslexia than in good readers. Because of these visual aspects of dyslexia, it is essential to visit an optometrist to rule out vision issues that may be contributing to difficulties, and to test for visual stress to identify and treat visual perceptual problems.
People with photosensitive epilepsy have up to a 14% chance of having seizures precipitated by light or pattern. For some epilepsies, colour is an important factor. Individual differences in the effects of coloured light may cause some patients to benefit from spectral filters that in other patients would exacerbate their sensitivity.  These same filters are used to alleviate the symptoms of visual stress caused by sensitivity to patterns, flicker, colour and lights. These similarities would seem to indicate that it is important to trial precision tinted filters to determine if they might reduce the pattern and light sensitivity causing epileptic seizures.
Several neurological disorders, including Hallucinogen Persisting Perception Disorder (HPPD), report the presence of visual disturbances such as halos or auras around objects, visual trails, colour changes, illusions of movement, and distortions in objects. Visual stress is a condition characterized by sensory processing difficulties that lead to these types of misperceptions. They can be alleviated with the use of individually prescribed coloured filter lenses. You should investigate visual stress and the use of filters if these types of hallucinations are present.
MAL DE DEBARQUEMENT SYNDROME (MdDS)
Mal de Debarquement (MdDS) presents primarily with persistent sensation of motion as well as hypersensitivity to lights and motion, migraine, nausea, cognitive and physical fatigue, and perceptual distortions. These are also symptoms associated with visual stress and can often be alleviated with precision tinted filters and assistive tools.
Bright light and certain visual patterns can trigger a migraine attack, leading to photophobia and various visual disturbances, including blurring. Perceptual illusions and visual discomfort are reported by most migraine sufferers and those with frequent headaches. These phenomena suggest that visual stimulation and the consequent hyperactivity in the visual cortex are factors in triggering some migraine attacks. This visual cortical stress (i.e., visual stress) can result from activities such as reading, working on a computer, watching television, and seeing certain patterns throughout the day, and can often be reduced with the application of individually prescribed coloured filter lenses.
MULTIPLE SCLEROSIS (MS)
Patients with multiple sclerosis often report visual deficits. Colours may appear darker or washed out, and discrimination of visual stimuli may be impaired. As well, patients with multiple sclerosis report experiencing migraines, epileptic seizures, visual discomfort, perceptual distortions, and cortical hyperexcitability. These symptoms are all common to visual stress, a hyperexcitement of the visual cortex that leads to physical discomforts such as eye strain and headaches, and perceptual distortion of visual stimuli in the environment and when reading. Some patients with photosensitive epilepsy, migraine, autism and dyslexia have also reported these symptoms which are frequently reduced with precision tinted filter lenses.
MYALGIC ENCEPHALOMYELITIS / CHRONIC FATIGUE (ME/CFS)
Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) is a condition that causes persistent fatigue that does not go away with sleep or rest. Diagnosis of the condition is difficult as its symptoms are similar to other illnesses, including those of visual stress such as headaches, cognitive and physical fatigue, reading difficulties, and disequilibrium. It is important to investigate visual stress when ME/CFS is diagnosed to rule out and treat visual stress if it is contributing to symptoms.
POST-CONCUSSION / ACQUIRED BRAIN INJURY (ABI)
Pattern glare (sensitivity to patterns) and photophobia (light sensitivity) have known association with a range of conditions both genetic or acquired. Many of these are neurological conditions such as migraines, epilepsy, autism, dyslexia, multiple sclerosis, stroke and visual stress. Individuals often report sensitivities to pattern and light following a concussion or acquired brain injury (ABI). Coloured overlays and precision tinted lenses can provide an effective solution for the management of the symptoms associated with these conditions.
POST TRAUMATIC STRESS DISORDER
Many patients with Post-traumatic stress disorder (PTSD) feel overwhelmed in situations with high levels of sensory input, as in crowded situations multiple sensory characteristics. These difficulties might be related to subtle sensory processing deficits such as those found in individuals with visual stress. Visual stress is a neurological sensory processing difficulty triggered by patterns, contrast and movement that results in the hyperactivation of the visual cortex leading to symptoms that include headache, sensitivity to light, and perceptual distortions in the environment. Precision tinted filter lenses have been shown to reduce these symptoms so should be investigated as a potential tool to help manage symptoms of post-traumatic stress disorder.
SPECIFIC LEARNING DISABILITIES (SpLD)
A Specific Learning Disability (SpLD) is a disorder unrelated to intelligence, motivation, effort, or other known causes of low achievement, that makes an individual struggle in certain areas of learning, such as reading, writing or doing mathematics. Visual stress is a visual sensory processing disorder that can alter the appearance of printed text and the lines on writing and graph paper, making reading, writing, and doing math problems more difficult. If learning difficulties are identified it is prudent to investigate vision (with a qualified eye care professional) and visual perception by testing for visual stress. Once the clarity of the reading, writing and math material is improved, it will be easier to perform the learning tasks and address the issues specific to the learning difficulties.
There are many ways stroke can affect vision including difficulties with balance, depth perception, visual memory and cognitive deficits, double or blurred vision, and reading difficulties. Cortical hyperexcitability, a known cause of visual stress, can occur following a stroke. Stroke survivors often report sensitivity to patterns and light. These are known triggers to visual stress symptoms. The resulting adverse symptoms have been managed effectively with coloured overlays and individually prescribed coloured lenses (PCLs). Given this evidence, it would seem logical to explore the potential rehabilitation of visual difficulties using precision tinted lenses and related tools for stroke survivors.
Tourette’s Syndrome, Autism Spectrum Disorder and ADHD have been consistently shown to overlap clinically. A large proportion of individuals with ADHD or Autism have shown symptoms similar to that observed in those suffering from visual stress, and in recent studies, children with Tourette Syndrome have also shown symptoms of visual stress. If symptoms of visual stress including light sensitivity, computer intolerance, reading difficulty, eyestrain, headaches, and perceptual distortions are reported, visual stress should be investigated, as well as the assistive tools and technologies offered to relieve symptoms.
VESTIBULAR DISORDERS / MOTION SICKNESS
Dizziness, vertigo and disequilibrium are commonly reported symptoms with different meanings and different diagnosis, making it difficult to get a correct diagnosis. While reports of unsteadiness, perception of movement, and imbalance may be caused by several vestibular disorders, these symptoms could also be attributed to the perceptual distortions experienced by individuals with visual stress. With visual stress, patterned images in the environment or text, can appear to move, shake, warp and shimmer, causing the sensation of movement or instability. It is important to include visual stress when investigating possible causes of symptoms and investigate individually prescribed coloured filter lenses as a means to relieve symptoms.
Visual snow, migraine and visual stress all involve reports of symptoms of perceptual illusions and distortions, often with discomfort. The perceptual distortions and discomfort reported in visual stress and migraine have been demonstrated to be reduced with the use of individually prescribed coloured lenses, associated with a reduction of neurological hyperactivation during brain scans. It would make sense then to rule out visual stress if perceptual distortions are reported.