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Background: The aim of this study was to measure the changes in the bacterial bioburden in orthokeratology (OK) lens storage cases using the DNA dot hybridization assay (DHA) after forewarning patients about their bacterial contamination severity., Methods: Thirty-one OK lens wearers were prospectively enrolled in this study. Dot hybridization assay was used for serial measurements of bacterial bioburden in OK storage cases after lenses had been soaked for approximately 6 hr. After the first assessment, the lens wearers were informed of the extent of case contamination and the possible risk of microbial keratitis (MK), and best practices for lens care and lens case hygiene were reviewed and reinforced. A second assessment by the same DHA method was performed after approximately 6 months., Results: Two universal bacterial probes confirmed a significant decrease in bacterial bioburden at the second assessment (P<0.01 and P<0.001). Genus-specific probes showed significant reductions in Acinetobacter and Klebsiella (P=0.02 and P=0.01), but not in Pseudomonas (P=0.42)., Conclusions: Making OK lens wearers aware of the bacterial bioburden in their lens cases resulted in improved quality of case care and reduced bioburden. Our results suggest that a strategy of bioburden assessment with forewarning could be a useful method to decrease the incidence of OK-related MK.

Objective: To assess the bioburden in an orthokeratology contact lens (OK) care system (defined by microbial identification from OK case fluid) and to identify the risk factors causing high bioburden for pediatric OK wearers in southern Taiwan., Methods: A prospective study for the investigation of bioburden in the OK care system was performed in a tertiary medical center in southern Taiwan. Microbial isolates from the case fluids soaking OKs were analyzed, and pathogenicity was determined. Age, gender, OK experiences, and contact lens care habits were considered the potential risk factors of microbial bioburden (colony-forming units per milliliter) for causal analysis., Results: Forty-one OK wearers (20 female and 21 male subjects) participated in this study. The mean age was 12.7 years, and the mean OK-wearing experience was 3.5 years. A total of 86 microbial strains were isolated from 38 culture-positive specimens. Frequently reported pathogens in contact lens-related microbial keratitis were less common in the current study, but still present, including 4 strains (5%) of Serratia marcescens, 1 strain (1%) of Pseudomonas aeruginosa, and 1 strain (1%) of Staphylococcus aureus. Microbial bioburden of the OK care system was significantly higher (P<0.05) in male subjects., Conclusions: The contamination rate of the OK care system was high, and many isolated microorganisms had potential pathogenicity. Reinforcement of proper contact lens care and education should be mandatory for OK wearers, particularly for male subjects, to decrease the risk of high bioburden of the OK care system.