Sir,

We thank Somner and Lockington for their comments. They bring an interesting perspective to the debate of disposable vs non-disposable tonometer heads. The financial and environmental impact of the disposable tonometer they describe has not been described in this detail before and may influence the practice of units in the United Kingdom.

The national survey on tonometer disinfection highlights that units in the United Kingdom may be using disinfection practices that are insufficient based on currently published guidelines. The facts that some units do not have two tonometers per doctor, that soaking times may be inadequate for sufficient disinfection, that rinsing practices of tonometers may not be sufficient, and that the strength and type of disinfection solutions in use may not be appropriate all lead us to believe that this may leave patients at risk of cross contamination and an iatrogenic infection.1

Outbreaks of epidemic keratoconjunctivitis from well reputed eye units have been documented, and tonometers have been implicated as one of the potential sources for the spread of these epidemics.2, 3

The department of health has instituted an advisory committee for dangerous pathogens (ACDP), for transmission of spongiform encephalopathy, with an ophthalmic subgroup, which is in the process of drafting guidelines for disinfection practices for instruments used in the specialty. Their guidelines are due to be published towards the end of 2008 and include a disinfection guideline for non-disposable instruments (including tonometer heads), which will be more stringent and potentially more difficult to adhere to than currently published guidelines. Their guidelines will recommend that if strict disinfection practices cannot be adhered to, the use of disposable instruments should be considered when these are available (personal communication from the ACDP, Ophthalmology subgroup).

We believe that units that cannot adhere to a safe and acceptable tonometer disinfection practice, which adheres to published guidelines, should consider the use of a disposable tonometer head as the financial, legal, and public relations impact of an outbreak of epidemic keratoconjunctivitis or the iatrogenic spread of infection because of inadequate disinfection practices would be considerable.