Vingrys A J, Helfrich K A, Smith G
Department of Optometry, University of Melbourne, Victoria, Australia.
Optom Vis Sci. 1994 Aug;71(8):508-15. doi: 10.1097/00006324-199408000-00004.
We report two experiments that address the role of stereopsis in viewing the fundus.
Thirteen observers viewed stereo slides obtained by lateral displacement of a fundus camera. We quantified the capacity of seven clinicians (normal stereopsis) to resolve depth in a model eye viewed monocularly and binocularly. We also compared the ability of the same seven and six additional clinicians (with reduced stereopsis) to determine the relative position of the cup shown in normal and reverse disparity as well as answering a questionnaire. We determined optimal performance based on a schematic eye.
Monocular viewing gives better than expected results with binocularity being of greatest benefit for small disparities. Clinicians perform much worse in stereoscopic judgments than predicted by calculation. Few clinicians report making stereo depth judgments in practice. All amblyopic observers report using hyperacuity cues.
This study shows that binocularity and stereopsis are beneficial for judging small disparities under limited circumstances. The level of stereopsis achieved in practice fails to approach the expected limit. We believe that this constriction arises from a known limit to stereo acuity associated with extended fields.
我们报告两项针对立体视觉在眼底观察中作用的实验。
13名观察者观看通过眼底相机横向移位获得的立体幻灯片。我们量化了7名临床医生（具有正常立体视觉）单眼和双眼观察模型眼时分辨深度的能力。我们还比较了这7名临床医生以及另外6名（立体视觉降低）临床医生确定正常和反向视差中所示视杯相对位置的能力，并让他们回答一份问卷。我们基于简化眼确定最佳表现。
单眼观察得出的结果优于预期，双眼观察对小视差最有益。临床医生在立体判断中的表现比计算预测的要差得多。很少有临床医生报告在实际操作中进行立体深度判断。所有弱视观察者都报告使用了超敏锐度线索。
本研究表明，双眼视觉和立体视觉在有限情况下有助于判断小视差。实际达到的立体视觉水平未达到预期极限。我们认为这种限制源于与扩展视野相关的已知立体视敏度极限。
