A Neurological Basis for Visual Discomfort

Abstract

Certain patterns of stripes are judged to be unpleasant to look at. They induce illusions of colour, shape and motion that are sometimes perceived predominantly to one side of fixation. People who suffer frequent headaches tend to report more illusions, and if the pain consistently occurs on the same side of the head the illusions tend to be lateralized. The parameters of the patterns that induce illusions (including their shape, spatial frequency, duty cycle, contrast and cortical representation) closely resemble those that elicit epileptiform electroencephalographic abnormalities in patients with photosensitive epilepsy. The viewing conditions under which such abnormalities are likely to appear are also those under which more illusions are seen.

Lighting Quality and Energy-Efficiency Effects on Task Performance, Mood, Health, Satisfaction, and Comfort

“…Other questions concerned personal and family health, including disorders such as migraine, high blood pressure, and epilepsy, which may relate to sensitivity to flicker. 50 Other individual difference (personality, beliefs, and attitudes) variables were included because of their potential to bias the results. Actual and desired influence over the physical environment in everyday settings were assessed using the Survey of Personal Influence in Common Environments.…”

Accommodation to Uncomfortable Patterns

“…The first and fourth patterns had a spatial frequency close to 3 cpd and the contrast and luminance were high and should therefore have been aversive (Wilkins et al, 1984). The second pattern had a lower contrast and luminance and should therefore have been less aversive.…”

“…Grating patterns that evoke photoparoxysmal responses in the electroencephalograph in patients with photosensitive epilepsy are generally uncomfortable to view (Wilkins et al, 1984). Gratings…”

“…In this experiment, participants were shown four grating patterns that varied in their spatial frequency and contrast (see Figure 4). The high contrast, mid-range spatial frequency patterns are within the epileptogenic range and are the most uncomfortable to view (Wilkins et al, 1984), so if accommodation is responsible for or related to aversion, we would expect a larger accommodative lag to these patterns. Any effect of the uncomfortable pattern on accommodation should be more apparent when the accommodative demand is greater.…”

“…Such patterns are generally perceived as uncomfortable to view by healthy individuals and can evoke visual illusions. Some individuals are more susceptible to the illusions than others, and these individuals are generally more susceptible to headaches (Wilkins et al, 1984). Illusions are sometimes reported when reading text, and the illusions seen in text can resemble those seen in gratings: a rhomboid lattice, rainbow colours, and perceptual instability (Wilkins and Nimmo-Smith, 1987).…”