Multiplexing Prisms for Field Expansion.
Multiplexing Prisms for Field Expansion.
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DOI：
10.1097/opx.0000000000001102
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发表时间：
2017-08
期刊：
影响因子：
--
通讯作者：
Jung JH
中科院分区：
文献类型：
--
作者：
Peli E;Jung JH
用于场扩展的棱镜受到棱镜顶端的光学暗点的限制。对于有两只正常运作的眼睛的患者，单方面安装棱镜可以让另一只眼睛补偿暗点。由于根尖暗点，单眼患者的视野损失不能用传统的或菲涅尔棱镜扩大。为克服单眼视野扩张术中顶端暗点的局限性，研制了一种新型的光学器件--多路复用棱镜。具有交替棱镜和平板元件的菲涅耳棱镜装置叠加了移位和透视图像，从而创造了视野扩展所需的(单目)视觉混淆，并消除了根尖盲点。在不同的单眼条件下，我们演示了几种实现方式，并对其进行了初步评估。利用计算的视野和测量的视野将MxP的视场扩展与传统棱镜的视场扩展进行了比较。无尖端暗点的视野扩张术对伴有偏盲或周边视野狭窄的单眼患者有效。研究表明，对于只有一只眼睛的患者和双暂时性偏盲患者，MXPS可以增加鼻野。放置在远场的MXP可以扩大正常视野。验证了控制两幅图像对比度的能力。一种新的光学器件被证明在各种条件下具有场扩展技术的潜力。这些装置可能不贵，并且可以以美容可接受的形式构造。
Prisms used for field expansion are limited by the optical scotoma at a prism apex. For a patient with two functioning eyes, fitting prisms unilaterally allows the other eye to compensate for the scotoma. A monocular patient’s field loss cannot be expanded with a conventional or Fresnel prism due to the apical scotoma. A newly invented optical device, the multiplexing prism (MxP), was developed to overcome the apical scotoma limitation in monocular field expansion. A Fresnel–prism-like device with alternating prism and flat elements superimposes the shifted and see-through views, thus creating the (monocular) visual confusion required for field expansion and eliminating the apical scotoma. Several implementations are demonstrated and preliminarily evaluated for different monocular conditions with visual field loss. The field expansion of the MxP is compared with the effect of conventional prisms using calculated perimetry and measured visual field. Field expansion without apical scotoma is shown to be effective for monocular patients with hemianopia or constricted peripheral field. The MxPs are shown to increase the nasal field for a patient with only one eye and for patients with bitemporal hemianopia. MxPs placed at the far temporal field are shown to expand the normal visual field. The ability to control the contrast ratio between the two images is verified. A novel optical device is demonstrated to have the potential for field expansion technology in a variety of conditions. The devices may be inexpensive and can be constructed in a cosmetically acceptable format.