Duration 5min, Q&A 3min
Seasonal Variations in Bleb-Related Infections in Japan
To investigate the seasonal variations in bleb-related infections following glaucoma filtering surgery in Japan.
This multicenter, prospective, observational study was a sub-analysis of the Japan Glaucoma Society Survey of Bleb-related Infection conducted from April 2005 to March 2010 at 82 clinical centers in Japan. Totally, 170 bleb-related infections (including reinfections) were reported in 156 patients, involving 157 eyes.
We excluded 13 reinfections and analyzed 157 primary bleb-related infections for seasonal incidence and severity. To analyze the seasonal variation in incidence, Roger's test, which evaluates the significance for cyclic trends based on the efficient score vector calculated for one seasonal peak, was performed. The seasonal variation in severity of the bleb-related infections was evaluated with Pearson's Chi-squared test. Bleb-related infections were classified as follows: stage I, infections confined to the bleb site with a mild cell reaction in the anterior chamber; stage II, infections in which the anterior chamber was the main locus of infection, but no involvement of the vitreous; stage IIIa, mild involvement of the vitreous; and stage IIIb, more advanced involvement of the vitreous. Systemic, ophthalmologic, and microbial data were analyzed.
Results and Conclusion
Most patients were infected in January and February (23 and 18 infections, respectively), whereas few patients were infected in August, September, October, and November (9, 9, 11 and 8 infections, respectively). The analysis revealed a statistically significant seasonal variation for the incidence of bleb-related infection cases (P = 0.014). The ages of patients at the time of first infection was 59.3 ± 17.7 years [mean ± standard deviation (SD); range: 3-93 years], and the period between last glaucoma surgery and the first bleb-related infection was 6.9 ± 5.8 years (mean ±SD; range: 0.3-41 years). No statistically significant association was found between the seasonal variation and the severity of the bleb-related infections (P = 0.242). This study documented for the first time that lager numbers of bleb-related infections occur after filtering surgery in the winter in Japan. Low ambient temperatures and/or low levels of humidity, which are typical of Japanese winters, may influence the development of the bleb-related infections. We suspect that factors such as the immune status of patients, the condition of blebs, and the characteristics of the causative organisms could affect the occurrence of bleb-related infections. Further studies to determine the specific reason for the occurrence of bleb-related infection will need to be undertaken.
[ Keyword ]
seasonal variation / bleb-related infection / filtering surgery / incidence / severity
[ Conflict of Interest ]