The effect of mental load on psychophysical and visual evoked potential visual acuity

Abstract

Visual acuity, the ability to detect detail in high contrast, is considered one of the most important visual functions in ophthalmic and visual evaluations. 1 Visual acuity can be affected by eye diseases such as maculopathies, 2 optical defocus caused by refractive errors [3][4][5] and other optical factors such as light scattering, aberrations, diffraction and accommodative fluctuations. 1,6 There are both subjective visual acuity tests, such as reading a letter chart, and objective evaluations, such as preferential looking and visual evoked potentials (VEP). Visual acuity assessment through

Effect of Cognitive Mental Load on Attended and Nonattended Visual Stimuli

“…The magnitude of mental load–induced changes in contrast thresholds was also greater than those previously found by modulating visual attention 24 . In contrast to this, other work that evaluated visual acuity using a sweep visual evoked potential (VEP) technique found that mental load had an SF-tuned effect, with mental load preferentially impairing higher SF processing 26 . The results of these two studies are not necessarily in direct conflict, however.…”

“…The results of these two studies are not necessarily in direct conflict, however. The effects of mental load on high SF processing were relatively modest, producing a change of less than one line on a logMAR acuity chart 26 . Our relatively course sampling of SF in our current (three SFs tested) and previous (five SFs tested) 15 work may reduce the ability to find a significant interaction between mental load effects and SF, particularly using an ANOVA where SFs are treated as discrete categories.…”

“…The effects of mental load on high SF processing were relatively modest, producing a change of less than one line on a logMAR acuity chart. 26 Our relatively course sampling of SF in our current (three SFs tested) and previous (five SFs tested) 15 work may reduce the ability to find a significant interaction between mental load effects and SF, particularly using an ANOVA where SFs are treated as discrete categories. Furthermore, sweep VEP-being an objective measure related to activity in the primary visual cortex-may not necessarily manifest effects occurring at higher processing levels in the brain.…”

“…24 In contrast to this, other work that evaluated visual acuity using a sweep visual evoked potential (VEP) technique found that mental load had an SF-tuned effect, with mental load preferentially impairing higher SF processing. 26 The results of these two studies are not necessarily in direct conflict, however. The effects of mental load on high SF processing were relatively modest, producing a change of less than one line on a logMAR acuity chart.…”

Long‐term effects of methamphetamine abuse on visual evoked potentials

“…Another important point that should be considered is the effect of attention. It is well known that attention affects pattern‐reversal VEPs 38–40 and that methamphetamine decreases attention 41 . Several researchers have shown that methamphetamine users are significantly impaired in their ability to ignore irrelevant information 41,42 .…”