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International multi-center review of Diffuse Lamellar Keratitis Outbreaks: 12-year experience Simon Holland Doug Morck Yumi Ohashi WCCVI April 2010 authors.

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Presentation on theme: "International multi-center review of Diffuse Lamellar Keratitis Outbreaks: 12-year experience Simon Holland Doug Morck Yumi Ohashi WCCVI April 2010 authors."— Presentation transcript:

1 International multi-center review of Diffuse Lamellar Keratitis Outbreaks: 12-year experience Simon Holland Doug Morck Yumi Ohashi WCCVI April 2010 authors have no financial interests

2 Aim: To evaluate strategies for investigation and control of Diffuse Lamellar Keratitis (DLK) outbreaks

3 Methods Retrospective consecutive series 62 DLK outbreaks: 8 countries, 1998 – 2009 Site visits: 27 Investigations: review of surgical procedures, sterilization, environmental and instrument contamination with selective microbial and endotoxin sampling Definition: outbreak control – DLK incidence <2%

4 Results Outbreak control - 58/62, two clinics discontinuing LASIK and two closing Epidemic curve – to show effects of interventions

5 Results Probable principal causes identified and corrected with outbreak control were: –bacterial/endotoxin contamination of sterilizer reservoirs and short cycle sterilization (16) –ultrasound bath contamination (4) –environmental (4) –silicone oils on gloves (2) –disposable microkeratomes (8)

6 Comparison of Different Gloves Cl S C – Carbon N – Nitrogen O – Oxygen Na – Sodium Al – Aluminium Si – Silicon P – Phosphorus S – Sulphur Cl – Chlorine K – Potassium Ca - Calcium Glove “A” Glove “B” Glove “C” Glove “D” Silicone Oil

7 STATIM 2000 Sterilizer reservoir inner tubing to T-piece brass plug

8 Biofilm: Inner sterilization tubing Gram negative rods encased in biofilm

9 Intervention Dry heat sterilization Modifying or increasing time in steam sterilization Using disposable instruments High level of sterile procedure Enzymatic and biocide cleaning Improving air quality Moving clinics Polymyxin on the stromal bed Use of sterile distilled water

10 Discussion 1998-2004: predominantly sterilization issues, biofilm, endotoxins 2005-2009: early Femtosecond Lasers, possible lot contamination eg. with disposable microkeratomes, silicone oils on gloves Recurrences common – protocol breakdown, surveillance important Canadian study – DLK incidence 0.67% (0.61- 0.73, 95%CI), 72% attributed to outbreaks 2000 decreasing to 40% 2003 * Bigham, M et al, JCRS 2005

11 Conclusions Review of 62 Diffuse Lamellar Keratitis outbreaks demonstrates most are multifactorial and that sterilization issues and endotoxin contamination appear to be predominant causes Almost all DLK outbreaks can be successfully controlled


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