Infectious crystalline keratopathy and its management

Purpose Infectious crystalline keratopathy (ICK) is defined as microbial infection of the cornea in the absence of the host inflammatory response. It presents as slowly progressive crystalline opacities resembling needles, snowflakes or ferns and are filamentous or branching in pattern within the cornea stroma. Methods Pathogenesis: Streptococcus viridans is the most common cause of ICK but a range of fungi and bacteria have been isolated from cases of ICK. They are located within the corneal stroma within the interlamellar planes. The pattern of spread of bacteria within corneal tissue is determined by the compactness of the corneal stroma. Another common feature is reduced corneal sensation, abrogating the triple response reflex at the limbus and hence the lack of the host response. The diagnosis of ICK is made on history and examination as microbiological diagnosis by culture of scrapes is difficult. Histology of biopsy specimen confirms diagnosis. Results Medical treatment with broad spectrum topical anti‐microbial agents is initiated. Any concomitant use of topical steroids should be discontinued. If no resolution of infection occurs, surgery in the form of lamellar or penetrating keratoplasty or superficial keratectomy is required. The successful use of excimer laser therapeutic keratectomy and Nd:YAG laser in the treatment of ICK has been demonstrated in single case reports but these techniques need further evaluation. Conclusion The diagnosis of ICK is largely clinical. It is difficult to treat medically often requiring surgical intervention. Poor corenal sensation and steroid use are important predisposing factors.