Microsurgical observation of the posterior vitreous in patients with vitreous hemorrhage caused by Terson syndrome

PURPOSE: To describe features characteristic of vitreous hemorrhage in patients with Terson syndrome observed through a microsurgical scope. METHODS: Between May 2015 and February 2019, 12 eyes of 10 patients with vitreous hemorrhage occurring after subarachnoid hemorrhage (SAH) underwent pars plana vitrectomy. RESULTS: During vitreous surgery, we found 10 of 12 eyes did not have posterior vitreous detachment (PVD). Furthermore, we observed in 9 of the 10 eyes without PVD (90.0%) that there was no hemorrhage in the posterior vitreous cavity at the posterior pole while we removed vitreous hemorrhage. We confirmed that this clean space could be the posterior precortical vitreous pocket (PPVP). CONCLUSION AND IMPORTANCE: Terson syndrome may have no hemorrhage in the PPVP regardless of the presence of severe vitreous hemorrhage. The cases presented in our study may suggest one of the mechanisms of Terson syndrome.