Aim: To provide an insight into the current issues in assessing visually symptomatic readers and the role of the orthoptist in the management of these patients.
Methods: A literature-based review was undertaken to investigate the assessment of patients presenting with visual symptoms associated with reading. Areas related to binocular vision and visual stress, visual discomfort and illusions are covered. The importance of differentiating between the correction of visual discomfort and the correction of dyslexia is also highlighted.
Results: Visual symptoms associated with reading are common, particularly in struggling readers, and the incidence of binocular vision anomalies in these patients is high. An evidence base spanning more than 40 years has demonstrated that binocular vision anomalies are common in those who complain of symptoms when reading and that correction of these anomalies is associated with improvement in reading function. The production of visual distortions and discomfort and links with reading have been noted in the literature. The use of colour has also been advocated to reduce visual discomfort associated with reading, and theories of pattern glare, noise exclusion and hyperexcitability are still being pursued to try to improve our understanding of how colour affects visual processing and can reduce symptoms of headache and visual discomfort. In addition binocular vision anomalies and distortion of text known as visual stress can coexist, and differential diagnosis is required when trying to improve visual comfort when reading, thus providing a role for the orthoptist in such cases.
Conclusions: Orthoptists can play a vital role in the assessment of visually symptomatic readers and should modify their assessment, as well as considering a range of treatments when assessing visually symptomatic readers. They should, however, be clear that treating visual symptoms is not treatment for dyslexia per se but that alleviation of visual symptoms associated with reading can be beneficial to those with reading discomfort and can help those with dyslexia and those without known reading difficulties.