کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9348515 | 1263579 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Vernier acuity for stereodisparate objects and ocular prevalence
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
سیستم های حسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Question. How precisely can objects, located in different depth planes, be aligned to the same visual direction? Methods. Twenty normal observers were presented with vertical Vernier lines at various stereodisparities. They had to judge whether the lower, anterior line was located on the right- or left-hand side of the upper, posterior line. Results. Over a stereodisparity range from zero to 62â³, the threshold for detecting a lateral offset between the Vernier lines remained at the “hyperacuity” level of about 7â³. With larger stereodisparities, the threshold increased about fourfold, probably due to a mutual, partial suppression of the position signals from the right and left eyes. The reference point from which the observers judged the relative visual directions between stereodisparate objects was not located midway between the eyes; rather, it was often decentred towards the right or the left eye, meaning that the observers had an “ocular prevalence”. Their ocular prevalence was, however, not strong enough to have an effect on the Vernier acuity for stereodisparate objects. (Under pathological conditions like strabismic amblyopia, one should expect a 100% prevalence of the good eye, implying that the Vernier acuity reaches the monocular level, irrespective of any depth difference between objects.) Conclusion. Vernier acuity decreases with increasing stereodisparity. Ocular prevalence, occurring frequently among persons with normal eyes, has no effect on Vernier acuity for stereodisparate objects. For a typical everyday viewing condition, the reduced Vernier acuity beyond a stereodisparity of 62â³ means that, from a viewing distance of 40Â cm, precision mechanics have to guide their instrument as close as 0.4Â mm to a workpiece, until they can utilise their best position acuity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Vision Research - Volume 45, Issue 10, May 2005, Pages 1321-1328
Journal: Vision Research - Volume 45, Issue 10, May 2005, Pages 1321-1328
نویسندگان
Sven P. Heinrich, Miriam Kromeier, Michael Bach, Guntram Kommerell,