Serologic testing results for HHV (herpes simplex virus, varicella-zoster virus, Epstein-Barr virus, CMV, HHV-6, and HHV-7) were positive. The patient had no history of systemic diseases. Based on the ocular manifestation, idiopathic corneal endotheliitis with iridocyclitis was suspected; however, topical and systemic steroids (topical betamethasone, 0.1%, 4 times daily and oral betamethasone, 1 mg/d) and ocular antihypotensive therapy (timolol maleate, 0.5%, twice daily and oral acetazolamide, 500 mg daily) were ineffective, resulting in suspicion for a viral infection. After the patient provided informed consent, an aliquot of 0.1 mL of aqueous humor was collected from the affected eye5 and real-time PCR analysis for HHVs (herpes simplex virus 1 or herpes simplex virus 2, varicella-zoster virus, Epstein-Barr virus, CMV, HHV-6, HHV-7, and HHV-8) was performed. Our real-time PCR procedure5 detected only HHV-7 DNA, which amplified the U37 gene DNA of HHV-7 (126 base pairs) using a specific primer and probe6 (HHV-7 DNA copies, 4.1 × 105/mL). Twenty aqueous humor samples from patients with cataract without keratitis who were negative controls contained no HHV-7 DNA. These findings led to the diagnosis of HHV-7–related keratitis. The medications were replaced with topical ganciclovir, 1%, an antiviral agent not only for CMV but also for HHV-7, 6 times daily with a topical steroid (betamethasone, 0.1%, 4 times daily). Slitlamp examination, visual acuity measurements, and real-time PCR were performed throughout the clinical course (days 0, 14, and 28). After ganciclovir therapy was started, corneal edema and keratic precipitates ultimately resolved (Figure 2). The intraocular pressure gradually decreased to less than 15 mm Hg without hypotensive agents. The best-corrected visual acuity recovered to 20/20 along with improved slitlamp findings. The HHV-7 copies decreased after the start of ganciclovir therapy to an undetectable level with clinical improvement, and the antiviral therapy was terminated. The number of corneal endothelial cells in the affected eye decreased to 1052/mm2 during the recovery stage compared with 2432/mm2 in the unaffected eye. There has been no recurrence 1 year after treatment.