Charman W N
Department of Optometry and Vision Sciences, UMIST, Manchester, UK.
Ophthalmic Physiol Opt. 1996 Nov;16(6):474-85.
Current knowledge of the refractive shifts (twilight myopia, night myopia, dark focus) that occur as the luminance is progressively lowered from photopic levels is reviewed. In complete darkness, myopic changes of the order of 1 dioptre are typical in young adult subjects. These gradually diminish as presbyopia is approached. The possible role of these refractive changes in causing visual difficulties for young drivers on the road at night is considered. It is concluded that high mesopic levels (about 1 cd/m2) of road luminance produced by street and vehicle lighting are normally too great to allow significant refractive shifts to occur, although acuity will be reduced due to light-dependent neural changes. Under these circumstances it appears unlikely that specific night-driving prescriptions will be beneficial: the accurate correction of normal refractive errors is, however, more important during night than day driving due to the greater blur associated with the larger night-time pupil. Suggestions are made for further experimental work in this area.
本文综述了随着亮度从明视觉水平逐渐降低而出现的屈光变化（黄昏近视、夜间近视、暗焦点）的现有知识。在完全黑暗中，年轻成年受试者典型的近视变化约为1屈光度。随着老花眼的临近，这些变化会逐渐减小。本文还考虑了这些屈光变化对夜间道路上年轻驾驶员造成视觉困难的可能作用。结论是，街道和车辆照明产生的高中间视觉水平（约1坎德拉/平方米）的道路亮度通常过高，不会发生明显的屈光变化，尽管由于与光相关的神经变化，视力会下降。在这种情况下，特定的夜间驾驶处方似乎不太可能有益：然而，由于夜间瞳孔较大导致的模糊度更大，因此在夜间驾驶时准确矫正正常屈光不正比白天驾驶更为重要。本文还对该领域的进一步实验工作提出了建议。
