A 55-year-old woman presents to her physician complaining of acute pain and redness in her right eye, with nausea and vomiting. She repos seeing halos around lights. On examination, lacrimation, lid edema, conjunctival injection, a steamy cornea, and a fixed mid-dilated pupil are seen. She has markedly elevated intraocular pressure (IOP), and a visual acuity of 20/200 in her right eye. She has no family history of eye diseases. Which of the following is the most likely diagnosis?