The myth of upright vision. A psychophysical and functional imaging study of adaptation to inverting spectacles.
Level 4 - case-series / case-control
Small experimental case series with psychophysical testing and fMRI (graded by design analogy)
PubMed 10664787 · doi:10.1068/p2820
What was done
Four subjects wore inverting prisms and mirror spectacles continuously for periods of six to ten days. Researchers assessed visuomotor adaptation, subjective reports of upright vision, perception of shape from shading, and early visual cortex retinotopy using functional magnetic resonance imaging (fMRI).
What was found
The abstract reports no numerical data. Subjects demonstrated rapid adaptation of visuomotor functions without reporting a return of upright vision. Transformed visual image persistence was confirmed via shape-from-shading perception, and fMRI revealed no retinotopic reorganization in early visual cortical areas.
Why it matters
This study provides evidence against historical claims that wearing inverting optics leads to a perceptual reinversion to upright vision, suggesting motor adaptation occurs without early cortical sensory remapping.
Limits
The sample size is extremely small (n = 4), adaptation was limited to 6–10 days, and the abstract reports no quantitative measurements, confidence intervals, or control comparisons.
Cited by
- contradicts Wearing inverting prism glasses causes the perceived visual field to flip right-side up after an adaptation period of continuous wear.