Delayed recurrent hyphema following trabeculectomy: A case series of swan syndrome managed with anti-VEGF therapy

Swan syndrome refers to delayed recurrent intraocular bleeding caused by vascular ingrowth at the site of a prior surgical wound. Although classically described after cataract surgery, it has rarely been reported following trabeculectomy. We report three cases of Swan syndrome following trabeculectomy that were successfully treated with intravitreal bevacizumab. A 32-year-old pseudophakic patient with primary open-angle glaucoma developed recurrent microhyphema 28 months after trabeculectomy. Gonioscopy revealed neovascularization at the internal ostium. Diode green laser failed to prevent recurrence, following which intravitreal and subconjunctival bevacizumab resulted in complete regression of the abnormal vessels with no further episodes. A 36-year-old male with congenital glaucoma developed recurrent hyphema more than 25 years after trabeculectomy, which resolved following intravitreal bevacizumab without recurrence on follow-up. A 62-year-old patient with pseudoexfoliation glaucoma developed recurrent hyphema seven months after combined phacoemulsification and trabeculectomy. Gonioscopy demonstrated a vascular frond at the internal ostium, and a single intravitreal bevacizumab injection resulted in complete regression of the neovascularization and resolution of symptoms. Swan syndrome is an uncommon but important cause of delayed hyphema following anterior segment surgery, including trabeculectomy. Careful gonioscopic evaluation is essential for diagnosis. Intravitreal anti-VEGF therapy appears to be a safe and effective treatment option for this rare complication.