Microaerosol formation in noncontact 'air-puff' tonometry

J. M. Britt, B. C. Clifton, H. S. Barnebey and R. P. Mills
Department of Ophthalmology, University of Washington, Seattle 98195.

Attention has been directed recently to appropriate methods for sterilizing tonometers to inactivate the human immunodeficiency virus and other viruses that have been found in tears. Noncontact tonometry, utilizing a brief pulse of pressurized air, is an alternative that avoids the need for sterilization procedures. We used a camera and flash electrically coupled to an American Optical Non-Contact II tonometer (Cambridge Instruments Inc, Cambridge, Mass) or a Keeler Pulsair tonometer (Keeler Instruments Inc, Broomall, Pa) to photograph the corneal profile during tonometry. Most eyes revealed some degree of tear film dehiscence and microaerosol formation. While tears have not been implicated as a source of human immunodeficiency virus infection, the ease with which droplets, potentially contaminated with human immunodeficiency virus and other viruses, are dispersed is disturbing. "Air-puff" tonometry may not be aseptic as previously presumed.