An Unusual Manifestation of HSV-1 Uveitis Transforming into an Acute Iris Transillumination-like Syndrome with Pigmentary Glaucoma: A Reminder of Treatment Pitfalls in Herpetic Uveitis.

We report a case of herpes simplex virus type 1 (HSV-1) anterior uveitis evolving into an acute iris transillumination-like syndrome with secondary pigmentary glaucoma, highlighting diagnostic challenges and treatment considerations. A 61-year-old immunocompetent woman presented with unilateral anterior uveitis characterized by keratic precipitates and mild anterior chamber inflammation. The condition was initially treated with topical and subconjunctival corticosteroids without antiviral therapy. After an initial resolution of symptoms, upon the cessation of treatment, the patient developed features resembling unilateral acute iris transillumination (UAIT) syndrome with elevated intraocular pressure, diffuse pigment dispersion, and progressive iris transillumination defects. Aqueous polymerase chain reaction (PCR) testing confirmed the presence of HSV-1. Despite the initiation of antiviral therapy, the condition progressed to severe pigmentary glaucoma, with unreliable intraocular pressure measurements due to prior LASIK surgery. Cataract extraction, pars plana vitrectomy, and Ahmed valve implantation were performed, with only partial recovery of visual acuity. This case illustrates that HSV-1 uveitis can mimic or transition into a UAIT-like syndrome, possibly due to steroid use without concurrent antiviral treatment, which may exacerbate viral replication and damage to the iris pigment epithelium. Aqueous PCR testing aids in differential diagnosis, but indicative medical history and clinical findings should remain instrumental. Clinicians should maintain a high index of suspicion for herpetic etiology in anterior uveitis cases and initiate prompt antiviral treatment to prevent potentially sight-threatening complications.