Denion E, Béraud G, Marshall M-L, Denion G, Lux A-L
Service d'ophtalmologie, CHU de Caen, avenue de la Côte-de-Nacre, 14033 Caen cedex 9, France; Pôle de formation et de recherche en santé, faculté de médecine, Unicaen, 2, rue des Rochambelles, CS 14032, 14032 Caen cedex, France; Inserm, U 1075 COMETE, pôle de formation et de recherche en santé, 2, rue des Rochambelles, CS 14032, 14032 Caen cedex, France; Centre ophtalmologique du pays des olonnes (COPO), 9, rue du Maréchal-Leclerc, 85100 Les Sables-d'Olonne, France.
Médecine interne et maladies infectieuses, CHU de Poitiers, 86000 Poitiers, France; EA2694, université droit et santé Lille 2, 59000 Lille, France; Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Hasselt, Belgium.
J Fr Ophtalmol. 2018 Jan;41(1):62-77. doi: 10.1016/j.jfo.2017.08.003. Epub 2017 Dec 13.
Sclerotic scatter involves the scattering of incident light by the limbal sclera followed by entry of part of the scattered light into the cornea, where some of the light travels through total internal reflection to the other side, where it scatters a second time in the limbal sclera. It is then visible in the form of a limbal scleral arc of light. Sclerotic scatter has been used for decades to spot and delineate corneal opacities, which disrupt and scatter the light travelling through total internal reflection. To implement the technique, the slit beam and the binoculars of the slit lamp should be dissociated so that the limbal sclera is illuminated, while the binoculars are centered on the cornea. The technique does not provide any information as to the depth of corneal opacities and therefore needs to be complemented by direct illumination. The second sclerotic scatter may also be used clinically, for instance for diode cycloablation, the posterior part of the arc of light projecting 0.5mm behind the scleral spur. This article aims to describe the phenomenon of sclerotic scatter, explaining how the slit-lamp should be set to use this technique, describing its clinical applications (in the opacified cornea and in the normal sclera), showing that the limbal scleral arc of light of sclerotic scatter may be seen under certain circumstances in daily life with the naked eye and, finally, explaining how the arc of light differs from peripheral light focusing ("Coroneo effect").
巩膜散射是指入射光被角膜缘巩膜散射，随后部分散射光进入角膜，其中一些光通过全内反射传播到另一侧，在角膜缘巩膜再次散射。然后以角膜缘巩膜光弧的形式可见。几十年来，巩膜散射一直被用于发现和描绘角膜混浊，角膜混浊会干扰和散射通过全内反射传播的光。为实施该技术，裂隙灯的裂隙光束和双目镜应分离，以便照亮角膜缘巩膜，同时双目镜对准角膜。该技术无法提供关于角膜混浊深度的任何信息，因此需要辅以直接照明。第二次巩膜散射在临床上也可使用，例如用于二极管睫状体光凝，光弧的后部投射在巩膜突后方0.5毫米处。本文旨在描述巩膜散射现象，解释裂隙灯应如何设置以使用该技术，描述其临床应用（在混浊角膜和正常巩膜中），表明在某些情况下，日常生活中肉眼可见巩膜散射的角膜缘巩膜光弧，最后解释光弧与周边光聚焦（“科罗尼奥效应”）的区别。
