Pneumotonometry Using Sterile Single-use Tonometer Covers

Abstract

Current methods for cleaning pneumotonometer tips include soaking the removable tip in various chemical agents. Disadvantages of this technique include the potential for incomplete disinfection, corneal contact with cleaning solutions, tip damage or loss, and soaking time. The authors studied the use of an available, disposable latex cover placed over the pneumotonometer tip for measuring intraocular pressure (IOP) in 46 eyes with normal corneas from a glaucoma screening clinic and 141 eyes with normal and abnormal corneas from a cornea and external disease clinic. The mean absolute IOP difference comparing with and without the tonometer cover was 1.6 mmHg for the glaucoma screening patients and 1.8 mmHg for the cornea clinic patients. A tonographic-like effect due to repeated tonometry also was shown. An additional study measuring a series of known IOP values in a cadaver eye showed no significant difference between uncovered and covered readings. These data suggest that placement of a disposable, latex cover over the pneumotonometer tip enables accurate IOP measurements and is a sanitary and convenient alternative method to repeated chemical disinfection.