Comparison of different diagnostic contact lens disinfection methods used in ophthalmic department in Chinese hospitals

Abstract

AIM:To assess the disinfection methods of diagnostic contact lens and their efficacy in ophthalmology in China.METHODS: Ten Chinese hospitals were surveyed and indicated three commonly used disinfectants 0.05% sodium dichloroisocyanurate(NaDCC), 75% EtOH, or chloramphenicol eye drops(Minimssup>®: 0.5%). Lenses were infected with staphylococcus aureus, staphylococcus epidermidis, or pseudomonas aeruginosa, and then disinfected by; 1)wiping; 2)immersing in disinfectant for 5min; 3)immersing in disinfectant for 10min; n=9. Swab wipes from the lenses were cultured for 24h and colony-forming units were counted to assess bacterial load. Lens clarity was subjectively scored for each method.RESULTS: The bacterial load was 1×108/mL ×50μL/lense equals 5×106/lense. Of the three methods the use of 75% EtOH and NaDCC are significantly more effective when used for wiping compared to eye drops(P≤0.01). Wiping with NaDCC or EtOH significantly reduced bacterial load but results were variable and the threat of cross-infection is still present. They were effective if used for 10min, but EtOH adversely affected lens clarity in contrast to NaDCC which had no adverse affects on the lens. Chloramphenicol eye drops were ineffective.CONCLUSION: NaDCC immersion for 10min or longer appears to be a simple and effective way to disinfect diagnostic contact lenses during ophthalmic examination.

Keywords

• hospital infection
• chloramphenicol
• dichloroisocyanurate
• pseudomonas aeruginosa
• staphylococcus aureus
• staphylococcus epidermidis