Temporal Retinal Sensitivity In Mesopic Adaptation

BEATRIZ MATEZANZ; LUIS ISSOLIO; ISABEL ARRANZ; CRISTINA DE LA ROSA; JOSÉ MENÉNDEZ; SANTIAGO MAR; JUAN ANTONIO APARICIO

OPHTHALMIC AND PHYSIOLOGICAL OPTICS

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 31 p. 615 - 624

0275-5408

Purpose. Night driving is a complex visual task with severe implications on the safety of drivers and pedestrians safety. It is usually performed under mesopic or scotopic conditions and frequently, in the presence of transient glare sources which involve the adaptation of part of the central retina. The objective of this work is to analyze the time response of approximately the first 15º peripheral retina when part of it is exposed to transient and steady mesopic conditioning fields. Methods. Absolute visual thresholds, luminance thresholds under steady and transient adaptation fields with SOA300 (SOA: stimuli onset asynchronies) and 5 cd/m2 of background adaptation level were measured for three observers, always for temporal retina eccentricities from 0º to 14.5º at steps of 2.9 deg (from now on 0º, 3º, 6º, 9º, 12º and 15º) by using a two-channel Maxwellian view optical system. Adaptation field and stimulus subtended 1.05º and 0.45º respectively. Time course adaptation curves were also measured at 0º, 6º and 9º. Results. The absolute dark adaptation threshold (threshold measured at dark adaptation conditions or Lta) exhibits a decrease in peripheral retina due to rod contribution. Luminance thresholds vs. eccentricity curves for transient (LtSOA300) and steady (LtLA) mesopic adaptation fields intersect once or twice for the observers in the first 15º peripheral retina. Conclusions. While fovea shows a higher sensitivity than the analyzed peripheral retina, the speed of adaptation, measured from the visibility loss, is greater for retinal regions between 6º and 9º than for fovea or further retinal eccentricities.