Tonometer disinfection failure puts patients at risk

Many UK institutions are not compliant with current international guidelines on tonometer disinfection, according to a study published in the August 2008 issue of Eye.

Roxane J. Hillier, MRCOphtha of Manchester Royal Eye Hospital, UK and colleagues conducted a telephone questionnaire of a senior nurse at every ophthalmology unit with training recognition in the UK (n=155) to compare current tonometer disinfection practice with published guidelines. Of the respondents, 23% (n=35) were excluded immediately as they reported that they used only disposable tonometer heads. The remaining 77% (n=120) used either reusable or a combination of reusable and disposable heads.

A chlorine-based solution was used to disinfect 67% of units (n=80). The concentration of chlorine used ranged from 125 to 30000 ppm, although 63% of units (n=50) used a concentration of <5000 ppm, which is the strength of disinfection recommended in published guidelines. Other disinfectant solutions used included: isopropyl alcohol (n=18), hydrogen peroxide (n=12), chloramine (n=5), chlorhexidine (n=4) and peracetic acid (n=1). One tonometer head per practitioner was provided in 29% of units (n=29); it is likely that these practitioners do not have sufficient time to disinfect these heads between patients. All units questioned replenished disinfectant daily, which is adequate for all solutions except hydrogen peroxide: of the 12 units using this disinfectant, 75% (n=9) did not replenish the solution (as required) twice daily.

The researchers concluded that, although the disinfection practices vary quite widely across the country, most units in the UK do not meet internationally recommended health and safety guidelines on tonometer head disinfection, leaving patients vulnerable to the risk of infection.