A 22-year-old woman with a history of high myopia (-8.00 -3.75 × 011, right eye; -6.75 -3.75 × 174, left eye) presented to our clinic for implantable collamer lens (ICL) evaluation. Medical history was noncontributory. The patient's father had a history of glaucoma. Slitlamp and dilated fundus examination were unremarkable with a cup-to-disc ratio of 0.5 in both eyes and a myopic fundus. Intraocular pressures (IOPs) were 20 mm Hg in the right eye and 19 mm Hg in the left eye. Galilei G4 (Ziemer USA, Inc.) measured a white-to-white (WTW) distance of 12.98 mm in the right eye and 13.05 mm in the left eye and central corneal thickness of 512 μm in the right eye and 504 μm in the left eye. Ultrasound biomicroscopy (UBM) (Sonomed Escalon) displayed a sulcus-to-sulcus distance of 12.76 mm in the right eye and 12.75 mm in the left eye and an anterior chamber depth (ACD) of 3.57 mm in the right eye and 3.79 mm in the left eye (Figure 1JOURNAL/jcrs/04.03/02158034-202409000-00014/figure1/v/2024-08-19T175148Z/r/image-tiff). Prednisolone acetate 0.1% ophthalmic suspension eye drops and ofloxacin 0.3% ophthalmic solution eye drops 4 times daily were prescribed prophylactically 2 days preoperatively. A -12.5 and -12 D EVO+ Visian toric ICL -13.2 mm (STAAR Surgical Co.) was implanted along the 180-degree meridian in the right eye and left eye, respectively. Immediate postoperative IOPs were 23 mm Hg in both eyes. The patient was instructed to continue ofloxacin drops for 1 week and taper prednisolone acetate drops over 1 month. On postoperative day (POD) 1, uncorrected distance visual acuity (UDVA) was 20/20 in the right eye and 20/25 in the left eye. The patient's IOP was 24 mm Hg in the right eye and 26 mm Hg in the left eye. Anterior chambers (ACs) were unremarkable with minimal edema at the clear temporal corneal incision sites. Anterior segment optical coherence tomography (AS-OCT) vault measurements were 766 μm in the right eye and 697 μm in the left eye. Subsequently, the prednisolone dosage was reduced to 3 times a day, and brimonidine eye drops 3 times a day in both eyes were added to the regimen. On POD 5, the patient returned to the clinic reporting sudden-onset blurred vision with severe retro-orbital pain in the left eye upon awakening. Her UDVA was 20/25 in the right eye and 2/40 in the left eye. IOP was 30 mm Hg in both eyes. The ACs were deep, and there was minimal corneal edema in both eyes. Vaults were 674 μm in the right eye and 623 μm in the left eye (Figure 2JOURNAL/jcrs/04.03/02158034-202409000-00014/figure2/v/2024-08-19T175148Z/r/image-tiff). The patient was instructed to reduce prednisolone to 2 times a day, discontinue brimonidine, and start brimonidine/timolol (Combigan) 2 times a day and latanoprost at bedtime in both eyes. At the routine 1-week postoperative appointment, the patient's IOP was 30 mm Hg in the right eye and 29 mm Hg in the left eye. The patient was instructed to reduce prednisolone to once a day, continue brimonidine/timolol 2 times a day and latanoprost at bedtime, and start acetazolamide (Diamox) 250 mg 2 times a day. The patient was told to return to the office in a few days for an IOP check. What are the differential diagnoses concerning this case? What is the most likely mechanism underlying this patient's elevated IOP? What additional diagnostic workup would aid you in making the correct diagnosis?