Nanoindentation-induced mechanical deformation in GaN thin films prepared by metal-organic chemical-vapour deposition was investigated using the Berkovich diamond tip in combination with the cross-sectional transmission electron microscopy (XTEM). By using focused ion beam milling to accurately position the cross-section of the indented region, the XTEM results demonstrate that the major plastic deformation was taking place through the propagation of dislocations. The present observations are in support of attributing the pop-ins that appeared in the load–displacement curves to the massive dislocation activities occurring underneath the indenter during the loading cycle. The absence of indentation-induced new phases might have been due to the stress relaxation via the substrate and is also consistent with the fact that no discontinuity was found upon unloading.

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Vascular occlusion causing vision loss is a rare yet one of the most devastating complications of facial esthetic fillers. In this article, we present a case of unilateral blindness and superficial skin necrosis in a 31-year-old woman after the injection of hyaluronic acid for esthetic purposes. The delicate ocular fundal findings of ophthalmic artery occlusion were demonstrated by ophthalmoscopy, optical coherence tomography, and fluorescein angiography. Magnetic resonance imaging also showed subsequent ischemic changes in the optic nerve and posterior scleral wall after ophthalmic artery occlusion. Despite management including intraocular pressure-lowering agents, globe massage, and anticoagulation with acetylsalicylic acid and hyperbaric oxygen therapy, her final vision was not restored. Given the lack of effective treatments, this report depicts the comprehensive ocular fundal findings of an ophthalmic artery occlusion after esthetic hyaluronic acid filler injection, and highlights the importance of a preventive approach to avoid such catastrophic complications.