Abstract
Purpose:
Exposure to high altitudes is a known risk factor for retinal hemorrhages previously reported in healthy mountain climbers. We report two cases of large vitreous hemorrhage associated with air travel in patients with recent PRP for retinal neovascularization. We aim to propose a novel idea of potential need to postpone exposure to high altitudes for patients with known neovascularization.
Methods:
Retrospective case series of two patients exposed to high altitude (air travel of 30,000 feet or higher) within one week of undergoing PRP treatment for active retinal neovascularization. Both patients developed vitreous hemorrhages with loss of vision within one day of air travel. Patient A had proliferative diabetic retinopathy (PDR) and traveled 2 days after the procedure. Patient B had proliferative sickle cell retinopathy and flew one week after his treatment.
Results:
Patient A is a 69 year-old male, with PDR, status post PRP two days prior to air travel. Visual acuity (VA) decreased from 20/40 to hand motion with dense vitreous hemorrhage. Patient B is a 52 year-old male with proliferative sickle cell retinopathy (four clock hours of retinal neovascularization). He received scatter laser treatment and one week later, experienced loss of vision due to dense vitreous hemorrhage at high altitude. VA decreased from 20/25 to hand motion. There was no retinal detachment seen on B-scan ultrasonography in either patient. The hemorrhages cleared within 3 months in both patients with regressed retinal neovascularization and vision restoration to baseline on follow-up exams.
Conclusions:
High altitude is associated with retinal vessel engorgement under hypoxic conditions and self-limited hemorrhage in healthy mountain climbers. This is the first report of two patients with active neovascularization that developed visually significant vitreous hemorrhage at high altitude. This is most likely related to engorgement of neovascular fronds that already have a predisposition to bleeding due to lack of normal endothelial tight junctions. PRP induces regression of neovascular vessels over several weeks. Patients may need to be cautioned against exposure to high altitudes in the immediate post-laser period when neovascularization has not yet regressed. Alternatively, intravitreal anti-VEGF treatment may be a potential option to prevent vitreous hemorrhage in patients that cannot delay air travel.
Keywords: 700 retinal neovascularization •
578 laser •
548 hypoxia