Polymerase chain reaction and DNA typing for diagnosis of infectious crystalline keratopathy

A 63-year-old man developed infectious crystalline keratopathy (ICK) in his right eye 1 year after phacoemulsification. The white peripheral lesion was adjacent to the corneal phacoemulsification incision. Infiltrates in the form of creamy-white, midstromal branching, needle-like opacities without evidence of inflammatory cells were noted. A corneal biopsy by double lamellar flap was done and studied by 3 techniques: microbiological culture, stain, and polymerase chain reaction (PCR). Fungal and bacterial PCR were positive. A second sample was necessary to obtain a positive stain and culture. The DNA sequence analysis showed Candida parapsilosis and Staphylococcus aureus as the causal agents of the crystalline keratopathy. Treatment was started with amphotericin B 1% and cefazolin 6 times a day, and systemic voriconazole was recommended. This is the first reported case of ICK after cataract surgery. Polymerase chain reaction amplification and subsequent DNA typing were useful tools in detecting and identifying the ocular pathogens involved in this case.