| 释义 |
angioscotoma
angioscotoma [an″je-o-sko-to´mah] a defect in the visual field caused by the shadow of the retinal blood vessels.an·gi·o·sco·to·ma (an'jē-ō-skō-tō'mă), Ribbon-shaped defect of the visual fields caused by the retinal vessels overlying photoreceptors. [angio- + G. skotōma, dizziness, vertigo] an·gi·o·sco·to·ma (an'jē-ō-skō-tō'mă) Ribbon-shaped defect of the visual fields caused by the retinal vessels overlying photoreceptors. [angio- + G. skotōma, dizziness, vertigo]angioscotoma A scotoma produced by the shadow cast by the retinal blood vessels. It looks like the branches of a tree extending from the blind spot. It is seen only in special conditions of illumination as when illuminating the fundus of the eye by gently moving a penlight over the closed eyelid, or when illuminating the fundus through the sclera, or when plotting the visual field. This phenomenon is sometimes used as a test to predict gross macular function in a patient with dense cataract where visualization of the fundus is impossible, although better results are obtained with the blue field entoptoscope. Syn. Purkinje figures; Purkinje shadows; Purkinje tree. See entoptic image. |