Motion sickness amelioration induced by prism spectacles.

A side effect of the prescription of prism glasses according to the principle of Utermöhlen to improve mechanical reading skills of certain types of learning disabled children was the alleviation of car sickness. Besides a decrease in reported symptoms after prescription of these glasses, the effect is quantified by a decrease in estimated number of emeses per year per patient. A placebo effect is unlikely because alleviation of car sickness was not the original intention of the prescription, and the symptoms returned as soon as the spectacles were discontinued.