Friberg T R, Weinreb R N
JAMA. 1985;253(12):1755-7.
To determine the ocular manifestations of inverting the human body into a head-down vertical position, we evaluated normal volunteers with applanation tonometry, fundus photography, fluorescein angiography, and ophthalmodynamometry. Compared with data obtained in the sitting position, the intraocular pressure more than doubled on inversion (35.6 +/- 4 v 14.1 +/- 2.8 mm Hg, n = 16), increasing to levels well within the glaucomatous range. Pressures in the central retinal artery underwent similar increases, while the caliber of the retinal arterioles decreased substantially. External ocular findings associated with gravity inversion included orbital congestion, conjunctival hyperemia, petechiae of the eyelids, excessive tearing (epiphora), and subconjunctival hemorrhage. We suggest that patients with retinal vascular abnormalities, macular degeneration, ocular hypertension, glaucoma, and similar disorders refrain from inversion altogether. Whether normal individuals will suffer irreversible damage from inversion is uncertain, but it seems prudent to recommend that prolonged periods of inverted posturing be avoided.
为了确定人体头朝下垂直倒立的眼部表现，我们使用压平眼压计、眼底摄影、荧光素血管造影和视网膜血流动力学测定法对正常志愿者进行了评估。与坐姿时获得的数据相比，倒立后眼压增加了一倍多（35.6±4 对 14.1±2.8 毫米汞柱，n = 16），升至青光眼范围内的水平。视网膜中央动脉的压力也有类似增加，而视网膜小动脉的管径则大幅减小。与重力倒置相关的眼部外部表现包括眼眶充血、结膜充血、眼睑瘀点、流泪过多（溢泪）和结膜下出血。我们建议患有视网膜血管异常、黄斑变性、高眼压症、青光眼及类似疾病的患者完全避免倒立。正常个体是否会因倒立而遭受不可逆损害尚不确定，但建议避免长时间的倒立姿势似乎是谨慎的做法。
