RESUMO
Purpose: The Enright phenomenon describes the distortion in speed perception experienced by an observer looking sideways from a moving vehicle when viewing with interocular differences in retinal image brightness, usually induced by neutral density filters. We investigated whether the Enright phenomenon could be induced with monocular pupil dilation using tropicamide. Methods: We tested 17 visually normal young adults on a closed road driving circuit. Participants were asked to travel at Goal Speeds of 40km/h and 60km/h while looking sideways from the vehicle with: (I) both eyes with undilated pupils; (II) both eyes with dilated pupils; (III) with the leading eye only dilated; and (iv) the trailing eye only dilated. For each condition we recorded actual driving speed. Results: With the pupil of the leading eye dilated participants drove significantly faster (by an average of 3.8km/h) than with both eyes dilated (p=0.02); with the trailing eye dilated participants drove significantly slower (by an average of 3.2km/h) than with both eyes dilated (p<0.001). The speed, with the leading eye dilated, was faster by an average of 7km/h than with the trailing eye dilated (p<0.001). There was no significant difference between driving speeds when viewing with both eyes either dilated or undilated (p=0.322). Conclusions: Our results are the first to show a measurable change in driving behaviour following monocular pupil dilation and support predictions based on the Enright phenomenon (AU)
Objetivo: El fenómeno Enright describe la distorsión en la percepción de la velocidad experimentada por un observador que mira lateralmente desde un vehículo en movimiento, y la visión con diferencias interoculares en cuanto a luminosidad de la imagen en la retina, normalmente inducida por filtros de densidad neutra. Investigamos si el fenómeno Enright podría inducirse mediante dilatación monocular de la pupila utilizando tropicamida. Métodos: Realizamos pruebas a 17 adultos jóvenes con visión normal, en un circuito cerrado de conducción por carretera. Se solicitó a los participantes que viajaran a velocidades predefinidas de 40km/h y 60km/h mientras miraban a ambos lados del vehículo con: I) ambos ojos sin dilatación pupilar; II) ambos ojos con las pupilas dilatadas; III) dilatación únicamente en el ojo fijador; y IV) dilatación únicamente en el ojo no fijador. Registramos la velocidad real de conducción para cada situación. Resultados: Con la pupila del ojo fijador dilatada los participantes condujeron a una velocidad considerablemente superior (de 3,8km/h de media) que con ambos ojos dilatados (p=0,02); con la pupila del ojo no fijador dilatada los participantes condujeron a una velocidad considerablemente menor (de 3,2km/h de media) que con ambos ojos dilatados (p<0,001). Con el ojo fijador dilatado la velocidad fue superior, de 7km/h de media, a la velocidad con el ojo no fijador dilatado (p<0,001). No se produjo diferencia significativa entre las velocidades de conducción cuando miraban con ambos ojos, tanto estuvieran dilatadas las pupilas o no (p=0,322). Conclusiones: Nuestros resultados son los primeros que reflejan un cambio medible en el comportamiento conductor tras la dilatación monocular de la pupila, y respaldan las predicciones que se basan en el fenómeno Enright (AU)
Assuntos
Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Percepção de Profundidade/efeitos da radiação , Visão Monocular/efeitos da radiação , Pupila/efeitos da radiação , Distúrbios Pupilares , Projetos de Pesquisa , Análise de VariânciaRESUMO
PURPOSE: The Enright phenomenon describes the distortion in speed perception experienced by an observer looking sideways from a moving vehicle when viewing with interocular differences in retinal image brightness, usually induced by neutral density filters. We investigated whether the Enright phenomenon could be induced with monocular pupil dilation using tropicamide. METHODS: We tested 17 visually normal young adults on a closed road driving circuit. Participants were asked to travel at Goal Speeds of 40km/h and 60km/h while looking sideways from the vehicle with: (i) both eyes with undilated pupils; (ii) both eyes with dilated pupils; (iii) with the leading eye only dilated; and (iv) the trailing eye only dilated. For each condition we recorded actual driving speed. RESULTS: With the pupil of the leading eye dilated participants drove significantly faster (by an average of 3.8km/h) than with both eyes dilated (p=0.02); with the trailing eye dilated participants drove significantly slower (by an average of 3.2km/h) than with both eyes dilated (p<0.001). The speed, with the leading eye dilated, was faster by an average of 7km/h than with the trailing eye dilated (p<0.001). There was no significant difference between driving speeds when viewing with both eyes either dilated or undilated (p=0.322). CONCLUSIONS: Our results are the first to show a measurable change in driving behaviour following monocular pupil dilation and support predictions based on the Enright phenomenon.
