Supplementary Material for: Temporal protrusion of the optic disc implicated in central visual field abnormalities in high myopia: Two case reports

Introduction: Severe central visual field defects are frequently observed in eyes with high myopia. We report the clinical features of two patients each with a central visual field defect; they had high myopia with an extreme protrusion in the temporal part of the optic disc. This unique optic disc appearance has not been reported previously.
Case presentation: In 2 patients, a 54-year-old man and a 65-year-old woman, each was diagnosed with high myopia in the left eye with outward protruding of the optic disc toward the macula. Swept-source optical coherence tomography revealed a focal lamina cribrosa defect at the temporal edge of the protruding optic disc corresponding to the papillomacular bundle area of retinal nerve fiber, which was thin around the focal lamina cribrosa defect. Visual field examination showed a central visual field defect in the eye, whose pattern corresponded to the papillomacular bundle responsible area.
Conclusion: The development of a protrusion in the temporal part of the optic disc may result in a focal lamina cribrosa defect, and cause a central visual field defect in eyes with high myopia. A temporal protrusion of the optic disc may be an important risk factor for central visual field defects.

引言：高度近视（high myopia）患者的眼部常可见严重的中心视野缺损（central visual field defects）。本文报告2例伴中心视野缺损的高度近视患者的临床特征，该类患者视盘（optic disc）颞侧存在显著突出，此种特殊的视盘表现此前未见报道。
病例报告：2例患者分别为54岁男性与65岁女性，均被诊断为左眼高度近视，且视盘向黄斑（macula）方向向外突出。扫频源光学相干断层成像（Swept-source optical coherence tomography）显示，突出视盘的颞侧边缘存在局限性筛板缺损（focal lamina cribrosa defect），该区域对应视网膜神经纤维的视乳头黄斑束（papillomacular bundle）区域，且该区域周围的视网膜神经纤维层变薄。视野检查显示患眼存在中心视野缺损，其缺损模式与视乳头黄斑束支配区域相符。
结论：视盘颞侧突出的形成可能导致局限性筛板缺损，进而引发高度近视患者眼部的中心视野缺损。视盘颞侧突出或为中心视野缺损的重要危险因素。