Acute Onset of Dense Vitreous Hemorrhage Associated with Retinal Arterial Macroaneurysm on the Optic Disc

We present a rare case of acute onset of dense vitreous hemorrhage (VH) associated with ruptured retinal arterial macroaneurysm (RAM) on the optic disc. A 63-year-old Japanese man had undergone phacoemulsification combined with pars plana vitrectomy (PPV) including internal limiting membrane peeling in the right eye for a macular hole approximately 1 year before presentation. His decimal best-corrected visual acuity (BCVA) in the right eye was stable at 0.8 with no recurrence of macular hole. He visited our hospital emergently prior to his regular postoperative visit for a sudden decrease in visual acuity in the right eye. Clinical examinations and imaging tests revealed dense VH in the right eye, and we could not observe the fundus. B-mode ultrasonography of the right eye showed dense VH without retinal detachment and a bulge on the optic disc. His BCVA decreased to hand movement in the right eye. He had no medical history of hypertension, diabetes, dyslipidemia, antithrombotics, or ocular inflammation in both eyes. Accordingly, we performed PPV on the right eye. During vitrectomy, we found a RAM on the optic disc with retinal hemorrhage on the nasal side. We carefully reviewed the preoperative color fundus photographs and noticed that RAM was not present on the optic disc at the time of his visit 4 months earlier. After surgery, his BCVA improved to 1.2, the color of the RAM on the optic disc changed to grayish yellow, and optical coherence tomography images showed a shrunken RAM. RAM on the optic disc could cause VH early after its onset.