Herein, we report a case of acute failure of a previously successful trabeculectomy, following an infection with herpes zoster ophthalmicus (HZO). HZO remains a common infection, especially among elderly and immunocompromised patients. There is a strong link between HZO infection, the incidence of secondary glaucoma, and the need for glaucoma filtering surgery. Though, to our knowledge, there are no cases reporting on the effect that a concomitant infection may have on a previously successful trabeculectomy. In our case, a 76-year-old immunocompetent male with primary open-angle glaucoma in both eyes and a history of a successful right eye trabeculectomy 1 year earlier presented with acute primary HZO involving the ophthalmic branch of the right trigeminal nerve. Appropriate topical and systemic treatment was immediately initiated. Three days later, the trabeculectomy bleb showed hyperemia and flattening and concomitant rise of intraocular pressure was noted. A week later, the cutaneous signs were improving yet the trabeculectomy had failed and high intraocular pressure was established, requiring both topical and systemic antiglaucoma medications. Our study suggests that a previously successful trabeculectomy may manifest signs of compromise and subsequent failure following a HZO infection.