Prophylactic removal and microbiological evaluation of calcified plaques after pterygium surgery

Purpose The aim of this study was to investigate microbiological characteristics of prophylactically removed calcified plaques developed after pterygium excision, and to evaluate risk factors for the growth of microorganisms. Methods Only exposed calcified plaques developed at the same site of previous pterygium excision were prospectively removed in 15 eyes of 14 patients. Plaques were completely removed, divided into small pieces and evaluated for microbiological identification. Underlying scleral defects were reconstructed using a conjunctival autograft, amniotic membranes and scleral patch grafts according to the size and depth of the defects. Based on the results of microbiologic cultures, eyes were divided into two groups and risk factors for microbial growth were analyzed. Results At surgery, the mean age of the patients was 71.2 ± 5.8 years and 71.4 % were females. The mean time interval between pterygium excision and calcified plaque removal was 19.3 ± 13.8 years. Six of 15 (40 %) removed plaques showed bacterial growth, and Stenotrophomonas maltophilia was the most frequently isolated microorganism. The size of calcified plaques was the only risk factor for culture-positive results ( p = 0.045). Underlying scleral defects were successfully repaired without any serious complication. Conclusions Microorganisms can be isolated from calcified plaques developed at the site of previous pterygium excision, and the size of plaques is the only risk factor for culture-positive results. To remove potential source of infection, prophylactic removal of calcified plaques and scleral surface reconstruction should be considered, especially when the plaques are exposed and large.