Contamination of disposable tonometer prisms during tonometry

Area of Science:

• Ophthalmology
• Infectious Disease Transmission
• Medical Device Safety

Background:

• Applanation tonometry is crucial for measuring intraocular pressure.
• Concerns exist regarding prion transmission via reusable tonometer prisms.
• Disposable prisms are increasingly adopted in the UK to mitigate prion risks.

Purpose of the Study:

• To investigate bacterial and viral transmission risks associated with disposable tonometer prisms.
• To assess staff practices and perceptions regarding disposable prism use.
• To evaluate the potential for pathogen transfer from healthcare practitioners to patients.

Main Methods:

• Questionnaire distributed to staff performing applanation tonometry.
• Bacterial cultures performed on handled disposable prisms.
• In vitro model constructed to assess adenoviral transmission potential.

Main Results:

• Nearly 50% of staff reported touching the prism's applanating face.
• Bacterial contamination, including Staphylococcus and Bacillus species, was detected on prisms.
• Adenovirus transmission via disposable prisms was deemed possible by the model.

Conclusions:

• Disposable prisms may not eliminate all infection risks associated with applanation tonometry.
• Bacterial and viral contamination of disposable prisms poses a potential risk to patients.
• Further measures may be needed to ensure the complete asepsis of tonometer prisms.