1. Microbial contamination of orthokertology lens and accessories in young patients Roy Cheng 1, Pauline Cho 1, Maureen Boost 2 and Sindy Lai 2 1 School of Optometry, 2 Dept. of Health Technology & Informatics, The Hong Kong Polytechnic University Methods: 1) Px aged <16 years with  6-months OKL wearing experience were recruited. 2) LC of the care of lens and accessories were evaluated via questionnaire. 3) Microbial samples were collected from OKL surface, CL solutions and accessories. 4) Presence of organisms were identified using standard microbiological methods. 5) Contamination rates (contaminated item/total collected items) were calculated. Results: 1) 45 subjects (male: 53%, female: 47%) with mean age 12 ± 2.4 years were recruited. 2) 62% collected suction holder was contaminated by different ocular pathogens such as S.aureus, Ps. aeruginosa and S. marcescens. 3) About 30% lenses and lens cases were found to be contaminated. S. aureus and Ps. aeruginosa were commonly found. 4) 49% and 44% subjects did not clean and disinfect the lens case and suction holder properly. Introduction: Microbial keratitis is a serious corneal infection, which can causes permanent visual loss. The organisms may come from care system 1 and contact lens (CL) solution 2. However, to date, no information about the prevalence of microbial contamination of ortho-k lens (OKL), CL solution and accessories have been determined for ortho-k wearers in HK. References: 1. Donzis PB, Mondino BJ, Weissman BA. Microbial contamination of contact lens care system. Am J Ophthalmol 1987;104:325-332. 2. Mayo MS, Schlitzer RL, Ward MA, Wilson LA, Ahearn DG. Association of Pseudomonas and Serratia corneal ulcers with use of contaminated solution. Journal of Clinical Microbiology 1987 Aug;25(8): 1398-1400. Contamination rate: MPS:Solution10% Nozzles12% Normal saline:Solutions5% Nozzles11% CL cleaner:Solution2% Nozzles2% Artificial tears:Solution16% Nozzles26% Case:Right chamber24% Left chamber29% Suction holder:62% Lens surface:27% Table 1. Contamination rates of lenses, CL solutions and other accessories. Conclusion: Possible reasons for high contamination rates may be related to low level of compliance in disinfecting the lens case and suction holder regularly. Furthermore, some subjects used improper methods to disinfect their accessories. Level of compliance: Lens care: Lens case:Suction holder: Solution: High46%24% 71% Medium44%27%32%29% Low10%49%44%0% Table 2. The level of compliance of care of OKL, case, suction holder and CL solution. Purpose: 1) To determine the prevalence of microbial contamination of OKL, CL solutions and all accessories. 2) To evaluate the level of compliance (LC) of care of lens and accessories This study is supported by a research grant from The Hong Kong Polytechnic University Definition of levels of compliance: High: Good compliance reported for all procedures Medium: Occasional lapses reported with 1 procedure Low: Frequent lapses reported with 1 procedure or lapses with 2 or more procedures