Braun U, Braun M, Jonas J B
Augenklinik mit Poliklinik der Universität Erlangen-Nürnberg, Erlangen.
Klin Monbl Augenheilkd. 1997 Sep;211(3):213-4. doi: 10.1055/s-2008-1035124.
Visual disturbances after high altitude exposure were first reported in 1969. Later, the term "High Altitude Retinal Hemorrhage-HARH" has been used for the ensuing retinal hemorrhages and vascular engorgement.
A 31-year-old Caucasian male presented to our outpatient department 1 week after climbing Mt. Gosainthan in the Himalayas. He had spent 25 days without oxygen supply above 5000 meters, with a maximum of 8046 meters. He now complained of glare and decreased vision in twilight. Visual acuity was 20/25 OD and 20/20 OS. Ophthalmoscopy revealed intraretinal hemorrhages and tortuosity of dilated arterioles and venoles. After 6 weeks of gradual improvement, visual acuity was 20/20 OD and 20/16 OS with normal visual fields.
The hypoxia at high altitude causes increased retinal blood flow and blood volume possibly via autoregulatory mechanisms. Furthermore, retinal venous pressure can be increased by extreme physical exertion and Valsalva maneuvers during mountain climbing. A hypoxic retinal capillary bed exposed to increased retinal venous pressure predisposes to intraretinal hemorrhage. Retinal changes include marked increase of retinal vessel diameter with tortuosity of arterioles and venoles and hyperemia or edema of the optic disc. The intra- or preretinal hemorrhages often spare the macular area. These patients do not experience debilitating symptoms unless vitreous hemorrhage occurs. This may be potentially hazardous when the patient is still in the high mountains. Clinically, all these retinal changes are reversible within weeks. To prevent high altitude retinopathy, ascending slowly and use of supplemental oxygen is recommended.
1969年首次报道了高原暴露后的视觉障碍。后来，“高原视网膜出血-HARH”一词被用于描述随后出现的视网膜出血和血管充血。
一名31岁的白人男性在攀登喜马拉雅山的戈萨因山后1周来到我们的门诊。他在海拔5000米以上的地方度过了25天，最高海拔达到8046米。他现在抱怨在黄昏时出现眩光和视力下降。右眼视力为20/25，左眼视力为20/20。眼底检查发现视网膜内出血以及扩张的小动脉和小静脉迂曲。经过6周的逐渐改善，右眼视力为20/20，左眼视力为20/16，视野正常。
高原缺氧可能通过自身调节机制导致视网膜血流量和血容量增加。此外，登山过程中的剧烈体力活动和瓦尔萨尔瓦动作可增加视网膜静脉压。暴露于升高的视网膜静脉压下的缺氧视网膜毛细血管床易发生视网膜内出血。视网膜变化包括视网膜血管直径显著增加，小动脉和小静脉迂曲，以及视盘充血或水肿。视网膜内或视网膜前出血通常不累及黄斑区。除非发生玻璃体积血，这些患者不会出现使人衰弱的症状。当患者仍在高山上时，这可能具有潜在危险。临床上，所有这些视网膜变化在数周内均可逆转。为预防高原视网膜病变，建议缓慢上升并使用补充氧气。
