A Guide to Tonometer Prism Disinfection & Key Infection Control Measures

Eyecare professionals have an unwavering commitment to protect patients as well as staff members from infections while in the office. In order to accomplish this hefty feat, all instruments that contact the patient's ocular surfaces must be disinfected, including the tonometer prism disinfection. Failing to do so can result in infections being transmitted from:

  • From staff to patient
  • From patient to staff
  • Direct contact between patients
  • By contaminated instruments
  • Airborne transmission

Simply put, there are a vast number of ways, means, and opportunities where patients, staff, and eye care providers can be exposed to infection. Use the following information by Keeler Ophthalmic Instruments to protect everyone in the practice from eye infection.

Preventing Infections with Key Control Measures

All eyecare professionals should be familiar with key terms used to execute infection control procedures.


Disinfection is when you inactivate all pathogenic microbes. However, disinfection doesn't necessarily inactivate all microorganisms. For instance, disinfection techniques tend to not work for protozoa, fungi, and bacterial endospores. In most eyecare practices, disinfection is achieved by using chemical methods or heat and water.


Cleaning equipment is the process of removing foreign material with detergents, water, or enzymatic solutions. Cleaning is vital to prevent dangerous concentrations of infectious organisms caused by dried tears, mucus, cosmetics, or tissue.

Cleaning requires you to scrub all surfaces of instruments to get rid of debris. Isopropanol alcohol may be used on insoluble deposits remaining on surfaces. However, it's important to know that alcohol may damage certain materials, so it's a great practice to ensure the cleaning agent is compatible with the surface being cleaned.


Sterilization is a practice designed to remove every and any microorganism, including bacterial spores. In most instances, sterilization involves autoclaving, which is a process of exposing the instrumentation to high pressure and temperature.

One of the most cost effective and efficient methods of in-office sterilization is a small tabletop steam autoclave unit. Contrary to popular belief, boiling and the use of UV light are not acceptable methods of sterilization.

Ensuring Safety with Reprocessing

One of the key methods to ensure all hazardous material is removed is to reprocess instruments. Reprocessing involves the disinfection and cleaning and/or sterilizing a reusable device.

Once the instrument is completely sterilized, it's known to be in what is called a hygienic state cleanliness. Instruments in a hygienic state have very little to no threat to others, while sanitary conditions are clean and physically healthy.

Tonometer Prism Disinfection

Every instrument that comes into contact with the ocular surfaces of a patient, including tonometers, should be wiped clean. Afterwards, the equipment must be thoroughly sterilized and/or disinfected after every use. It's best to use single-use or disposable tonometer prisms and other types of disposable equipment when applicable.

All reusable instruments should be immediately cleaned, and then sterilized or disinfected based on the intended use. The most common items in an exam rooms that contacts the tears of patients and their cornea are applanation tonometer probes. As a result, it's extra important to ensure this equipment is properly maintained and cleaned before and after every use.

When it comes to tonometer prism disinfection, most manufacturers suggest not exposing the device to alcohol. Two separate reports have noted that while alcohol is effective for virus removal, it may cause damage in the process of Goldmann tonometer sterilization. Instead, the manufacturers suggest removing the prism and cleaning it with cold water and mild soap. Afterwards, the instruments should be soaked in a solution of 3% hydrogen peroxide for 10 minutes.

The instrument should be rinsed thoroughly with sterile saline, tissue drive, and kept in a dry, clean container. The tip of the device should covered with a latex cover, which is discarded after using.

Disinfection of Gonioscopy Lenses

The process of disinfecting gonioscopy lenses typically mirrors tonometer prism disinfection techniques. However, you should always consider the manufacturer's instructions. For instance, some manufacturers of gonioscopy lens suggests cleaning the entire lens with a clean soft cotton cloth and a mild cleaning solution.

The lenses can be disinfected with either a 1:10 dilution of household bleach or 2% aqueous glutaraldehyde. It's important to always use a fresh solution for every cleaning procedure. With the lens positioned on its side, the entire lens should be immersed for 25 minutes.

After the lens is removed from the solution, you should thoroughly rinse it with water at room temperature. Finally, dry the lens with a lint-free, soft cloth. Following disinfection, the gonioscopy lens should be stored in a container or a closed case.

Contact Keeler Ophthalmic Instruments

At Keeler Ophthalmic Instruments, we industry leaders in providing cutting-edge equipment and solutions. The ultimate decision for every clinic, practice, and hospital is to decide the best tonometer prism disinfection technique to reduce the likelihood of infection.

Contact Keeler Ophthalmic Instruments today.