Structural damage to Schiotz tonometers after disinfection with solutions

Although Schiotz tonometry has been long ago replaced by Goldmann applanation tonometry measurement of intraocular pressure, it remains a viable clinical technique in nursing homes and other "out of office" settings. Because Schiotz tonometers come into contact with the cornea and tear film, they must be properly disinfected to prevent cross-infection with HIV and other infectious pathogens. The Centers for Disease Control and Prevention (CDC) recommends that all eye contact devices be disinfected by a 5- to 10-min soak in one of following disinfectants: 3% hydrogen peroxide, 1:10 sodium hypochlorite (household bleach), or 70% isopropyl alcohol. The effects of these disinfectants on Schiotz tonometers have not been previously investigated. This study investigated the effects of CDC-recommended disinfectants on the structural integrity of Schiotz tonometers. The results of the study indicated that soaking in 1:10 sodium hypochlorite and 3% hydrogen peroxide damaged Schiotz tonometers and rendered them inoperable. Alcohol caused minor damage to the tonometer and was the safest of the CDC disinfectants. This study showed there is limited application of CDC infection control criteria to Schiotz tonometers due to the extensive corrosion and damage caused by hydrogen peroxide and bleach.