Atchison D A
Department of Optometry, Queensland Institute of Technology, Brisbane, Australia.
Ophthalmic Physiol Opt. 1987;7(3):259-65.
Defocus increased visual field contrast thresholds for stimuli equal to or smaller than Goldmann perimeter target III (26 min arc diameter). Beyond 30 degrees-40 degrees from the centre of the visual field, defocus had little effect on contrast thresholds. For accurate clinical perimetry, ametropia and presbyopia should be corrected for small targets (less than or equal to target III) within 30 degrees-40 degrees of fixation with either a spectacle lens (if required power less than +/- 10 D) or a contact lens. Larger stimuli are little affected by defocus. Outside this central 30 degrees-40 degrees field, correction with contact lenses should be provided if fixation is poor due to ametropia. Scotomata for which no cause is evident should be further investigated to find whether they have a refractive basis.
对于等于或小于戈德曼视野计目标Ⅲ（26分视角直径）的刺激物，散焦会提高视野对比度阈值。在距视野中心30度至40度以外，散焦对对比度阈值影响很小。对于精确的临床视野检查，对于在注视点30度至40度范围内的小目标（小于或等于目标Ⅲ），屈光不正和老花眼应使用眼镜镜片（如果所需屈光度小于+/-10D）或隐形眼镜进行矫正。较大的刺激物受散焦影响较小。在这个中央30度至40度视野之外，如果由于屈光不正导致注视不良，应佩戴隐形眼镜进行矫正。对于原因不明的暗点，应进一步检查以确定它们是否有屈光基础。
