Abstract
Interstitial keratitis (IK) is a non-ulcerative inflammatory disorder of the corneal stroma characterized by stromal inflammation and vascularization in the absence of primary epithelial or endothelial disease. While historically associated with syphilis, IK has been reported in association with a variety of infectious and autoimmune conditions, including herpes simplex virus (HSV), varicella-zoster virus, tuberculosis, and Lyme disease. Lyme-associated IK is uncommon and remains a diagnostic challenge. A patient from the northeastern United States with no significant past medical history presented with a two-year history of progressively worsening bilateral vision. Ophthalmic examination demonstrated findings consistent with bilateral interstitial keratitis. A comprehensive systemic and infectious evaluation was performed. Laboratory testing was negative except for positive Lyme disease serologies. Given the broad differential diagnosis for IK and the possibility of herpetic stromal keratitis, the patient was treated with topical corticosteroids and oral antiviral therapy, resulting in clinical improvement. Oral doxycycline was also initiated to address possible Lyme disease–associated ocular involvement. Unfortunately, the patient was subsequently lost to follow-up, limiting assessment of long-term outcomes and treatment response. This case highlights the importance of considering Lyme disease in the differential diagnosis of interstitial keratitis, particularly in endemic regions. Thorough systemic evaluation is essential, as identification of an underlying etiology may guide management and improve visual outcomes.
Presentation Date: 07/16/2026
Issue Date: 09/25/2026
