Krzizok T, Kaufmann H, Schwerdtfeger G
Universitäts-Augenklinik für Schielbehandlung und Neuroophthalmologie Giessen.
Klin Monbl Augenheilkd. 1996 Jun;208(6):477-80. doi: 10.1055/s-2008-1035267.
Cataract and refractive surgery aiming at emmetropia, runs the risk to induce binocular problems, e.g. asthenopia or diplopia. If the compatibility concerning binocularity is solely estimated by the calculation of the difference of the retinal image sizes, using intraocular lens formulas or so-called "aniseikonia-programs", important physiological facts are not considered. The actual amount of the aniseikonia, this is the difference of the image size which the patient perceives subjectively, depends on 3 parameters: 1. the optically induced difference of the retinal image size, 2. the spatial density of the retinal photoreceptors and the size of the receptive fields, 3. a possibly existing anomalous retinal correspondence for different retinal image sizes. Besides aniseikonia, the induction of postoperative anisophoria by the required spectacle correction is a considerable aspect. Aniseikonia and anisophoria can cause fusional problems or diplopia because of the mentioned parameters and/or disparity of the retinal images.
Cataract surgery should reduce a monolateral high myopia, aiming emmetropia, in axial anisometropia. This resulted in one exemplary case in high aniseikonia with complaints, while in other, comparable patients only a small amount of aniseikonia could be measured by haploscopy. This preoperative refractive situation is comparable to refractive surgery. In a second case with symmetrical myopia of -4 D, binocular problems with diplopia and asthenopia were induced after monolateral cataract surgery by the combination of a moderate aniseikonia and anisophoria.
To predict the actual postoperative aniseikonia it is necessary for the patient to wear a contact lens preoperatively for a short time to measure the aniseikonia by haploscopy, particularly prior to refractive surgery in axial length ametropia. Due to the different sizes of the receptive fields of the retina, different postoperative aniseikonias may result in spite of similar axial length anisometropia. The individual tolerance of an adult for a postoperatively created anisophoria is hardly predictable. It is obvious that the fusional stress ensued from aniseikonia and anisophoria adds or multiplies. In contrast to horizontal eye movements, vertical eye movements can hardly be compensated by head movements, as the use of bi- or multifocals requires a down gaze of about 30 degrees. Here a height-balance-prism could help.
旨在实现正视化的白内障和屈光手术存在诱发双眼问题的风险，例如视疲劳或复视。如果仅通过使用人工晶状体公式或所谓的“影像不等视程序”计算视网膜图像大小的差异来评估双眼视觉的兼容性，那么重要的生理事实就未被考虑在内。实际的影像不等视量，即患者主观感知到的图像大小差异，取决于三个参数：1. 光学诱导的视网膜图像大小差异；2. 视网膜光感受器的空间密度和感受野大小；3. 针对不同视网膜图像大小可能存在的异常视网膜对应。除了影像不等视外，所需眼镜矫正导致的术后隐斜也是一个重要方面。由于上述参数和/或视网膜图像的视差，影像不等视和隐斜可能会导致融合问题或复视。
白内障手术旨在矫正轴向性屈光参差中的单侧高度近视，实现正视化。在一个典型病例中，这导致了高度影像不等视并伴有相关症状，而在其他类似患者中，通过检眼镜检查仅能测量到少量的影像不等视。这种术前屈光状态与屈光手术类似。在第二个病例中，患者为对称的-4D近视，单侧白内障手术后，由于中等程度的影像不等视和隐斜共同作用，诱发了双眼复视和视疲劳问题。
为了预测实际的术后影像不等视情况，患者术前需要短时间佩戴隐形眼镜，通过检眼镜检查来测量影像不等视，尤其是在轴向长度性屈光不正的屈光手术之前。尽管轴向长度性屈光参差相似，但由于视网膜感受野大小不同，术后可能会出现不同程度的影像不等视。成年人对术后产生的隐斜的个体耐受性很难预测。很明显，影像不等视和隐斜所产生的融合应力会相加或相乘。与水平眼动不同，垂直眼动很难通过头部运动来补偿，因为使用双焦点或多焦点眼镜需要大约30度的向下注视。在此情况下，高度平衡棱镜可能会有所帮助。
