Cytomegalovirus Induced Infectious Crystalline Keratopathy After Penetrating Keratoplasty

Purpose: To report a rare case of post-penetrating keratoplasty infectious crystalline keratopathy caused by Cytomegalovirus (CMV). Methods: The patient's history, clinical presentation, laboratory, and imaging analysis were reviewed. Results: A 55-year-old male patient was referred to our hospital with a medical history of 3 prior penetrating keratoplasty procedures because of post-refractive surgery infectious keratitis and epithelial downgrowth. He has been on both systemic and topical immunosuppressive medications. The patient presented with decreased vision, and on examination, a needle-like branching corneal lesions was identified, consistent with the diagnosis of infectious crystalline keratopathy. After negative results from smear and culture of corneal samples, molecular evaluation using polymerase chain reaction testing revealed the presence of CMV. Consequently, immunosuppressive therapy was adjusted, and systemic and topical antiviral treatments were initiated, resulting in a favorable clinical response. Conclusions: This case emphasizes the importance of considering CMV infection in progressive and nonresponsive infectious crystalline keratopathy to antimicrobial medications, particularly in immunosuppressed individuals. In addition, polymerase chain reaction is an appropriate laboratory molecular diagnostic test for the accurate diagnosis of CMV keratitis.