Ocular Injury Caused by the Sprayed Venom of the Asian Giant Hornet (Vespa mandarinia)

Abstract

This report presents the details of a case of sight-threatening injury in the right eye of a 77-year-old man which was caused by the venom of the Asian giant hornet (Vespa mandarinia). The patient was not stung, rather the venom was sprayed into his eye. Although the injured eye was washed as a first aid treatment, persistent corneal defect, corneal endothelial decompensation, iris atrophy, pupil dilation, and mature cataract were observed and a hand movement visual acuity was recorded 8 weeks after the injury. Since a slight a-wave was detected in his electroretinogram (ERG) result after the corneal epithelial defect had healed, we performed cataract surgery and Descemet stripping automated endothelial keratoplasty (DSAEK). After the DSAEK, the cornea of the right eye became clearer; however, the visual acuity of his right eye did not improve. Fundus examination revealed branch retinal artery occlusion but no optic disc atrophy. ERG showed that the a-wave amplitude of the injured eye recorded after the surgery was almost half of that of the fellow eye. The iris atrophy and mature cataract show that the sprayed Vespa venom of the Asian giant hornet can permeate into the intraocular area even without stinging. Whether the venom directly affects retinal function is unclear, but the decreased a-wave of the injured eye shows that the venom caused damage of retinal function in some way. Irrigation of the anterior chamber as well as eye washing is needed as a first aid treatment in similar cases.

Keywords: Bullous keratopathy; Electroretinogram; Ocular injury; Sprayed venom; Vespa mandarinia.

Fig. 1

A bottle of Hachi-zake (hornet liquor), in which Asian giant hornets are soaked in brandy, that the patient brought for one of the authors (K.H.). This is drunk as a nourishing tonic.

Fig. 2

a Anterior segment findings of the injured eye under diffuse illumination at the patient's first visit. The cornea is hazy with stromal and epithelial edema and persistent corneal epithelial defect (stained by fluorescein). The pupil is dilated, and mature cataract can be seen. b Four months after DSAEK. Depigmented iris with dilated pupil indicates past history of severe iritis. DSAEK, Descemet stripping automated endothelial keratoplasty.

Fig. 3

a ERG recorded before the cataract surgery. The ERG of the right eye shows a reduced amplitude and prolonged implicit time in the a-wave compared with that of the left eye. b ERG of the right eye 4 months after DSAEK. Improvement is seen in the amplitude and the implicit time due to the improved transparency of the ocular media. c Fundus photograph taken 4 months after DSAEK. Though the image of the fundus is hazy because of the residual corneal stromal edema, the color of the retina looks normal and there are no signs of atrophy in the optic disc, but a ghost vessel can be seen in the lower temporal area (asterisk). DSAEK, Descemet stripping automated endothelial keratoplasty; ERG, electroretinogram.