Information was printed inaccurately in the 'How to’ article on applanation tonometry in Issue 64, December 2007. The corrections are shown here in bold.
Preparation
Ensure that the prism has been disinfected with isopropyl alcohol 70 per cent (methylated spirit) or sodium hypochlorite 1 per cent. The prism must be rinsed in sterile water and wiped dry with a clean swab (as residue of the disinfectant may cause a caustic burn on the cornea).
Method
When the applanation tonometry procedure has been completed:
Wipe the prism with a clean, dry swab and replace it in the receptacle containing the disinfectant.