The efficacy of acetone in the sterilisation of ophthalmic instruments.

Acetone has been considered a quick, effective and less expensive chemical sterilising agent and continues to be used by ophthalmic surgeons, at least in developing countries. Its utility however has been questioned recently. This study was designed to assess the efficacy of acetone against Pseudomonas aeruginosa, Bacillus subtilis and Aspergillus flavus present on ophthalmic surgical instruments (forceps, sutures). The instruments were contaminated by immersion in standard suspensions of the organisms and thereafter were either unwashed (group-I), washed and dried (group-II) or only washed (group-III) before immersion in acetone. The exposure to acetone was kept at 3, 10 and 20 minutes in each group. The results showed that acetone could eliminate Pseudomonas (vegetative bacteria) after 10 minutes exposure in unwashed group and 3 minutes exposure in washed groups. It was ineffective against spore bearing bacteria (B. subtilis) and fungus (Aspergillus flavus) even after 20 minutes of exposure.