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B. Osgood, K. A. Truax, T. T. McMahon, J. De La Cruz; Evaluation of Contact Lens Surface After Long-Term Use by Scanning Electron Microscopy in Patients With Boston KPro Type I. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1504.
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Patients with Boston Keratoprosthesis Type I require the use of a contact lens to help maintain a moist corneal surface and prevent degradation of the corneal skirt. The chronic use of topical antibiotics in these patients may promote the growth of resistant organisms, yet, to our knowledge, the surveillance of the contact lenses in these patients by scanning electron microscopy has not been performed. The purpose of this study is to perform such microscopy in order to detect possible biofilm formation and/or organism growth prior to the clinical presentation of infection.
Scanning electron microscopy of contact lenses from Boston KPro Type I patients was performed. Both Kontur large diameter lenses and Focus Night and Day (CIBA Vision) lenses were used, with selection based on adequate fit and patient comfort. All patients were maintained on a prophylactic antibiotic regimen including vancomycin. All contact lenses were removed one week to one month after placed, using sterile technique. Premature removal, prior to one month, was necessary only when excessive protein deposits were noted on the lenses. Lenses were placed into sterile BSS solution and, using sterile instruments, were cut into three pieces with one sent for scanning microscopy and the other two for culture.
Out of 45 patients with an implanted KPro in the last 18 months, the lenses of 15 patients were analyzed in the aforementioned manner. These patients had conditions varying from Stevens Johnson, chemical burns, keratoconus, multiple graft failures, and advanced glaucoma. Of the 15 lenses analyzed, scanning EM showed evidence of streptococcus pneumoniae in one patient, consistent with the patient's presentation of endophthalmitis. Three more lenses showed evidence of coagulase negative staphylococcus on scanning EM, although the patients did not present with any signs or symptoms of infection. The remainder of the lenses had no evidence of organisms noted on scanning EM.
Scanning EM appears to be an effective way to monitor the contact lenses of Boston KPro patients for possible organism/biofilm growth. The detection of these organisms prior to the clinical presentation of infection could serve as a possible sign of antibiotic resistance and the need for alteration of a patient's antibiotic regimen. This, in turn, could significantly reduce morbidity in this complex patient population.
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