How To Disinfect and Calibrate Your Tonometer

Apr 22, 2021 | Optometry

How To Disinfect and Calibrate Your Tonometer

Among the most important instruments in an ophthalmologist’s office is the tonometer, which measures the pressure of fluid within the eye. Most tonometers measure intraocular fluid pressure through applanation or direct contact with the cornea. Others simply rely on delivering a puff of air to the cornea and remotely measuring the depression that air puff made upon the eye’s surface—a less accurate but considerably less intrusive means of taking IOP. Because of the regular usage your tonometer sees, proper maintenance is necessary to ensure that it’s clean and accurate. In today’s post, we’ll look at how to disinfect and calibrate your tonometer in order to deliver safe and accurate IOP readings for your patients.


Because of the high traffic that your practice and tonometer see each day, properly disinfecting your tonometer is necessary to keep your patients safe. Even with the proper tip covers, the proximity of the entire unit to your patients requires you to disinfect and sterilize the instrument. Hydrogen peroxide, dilute bleach, and a 70 percent alcohol solution are three of the most common disinfectants for ophthalmology, though a bleach solution is most effective in killing viruses, bacteria, and other microorganisms. However, ophthalmologists must disinfect with care as these solutions can affect the integrity of the tonometer’s prism. Soaking prisms for too long can cause swelling, tip fractures, and degrading of the glue that holds tips together. Carefully examine well-disinfected prisms for any indications of damage and consider disposable tip covers as an added precaution.


After ensuring that the tonometer is safe to use for each patient, it’s imperative to ascertain that it’s properly calibrated. A Goldmann applanation tonometer, the gold standard for measuring intraocular pressure, usually requires calibration once every six months in its first year and once every month thereafter. Your Goldmann tonometer should come with an array of weight bars for calibration. If you opt for a handheld tonometer, you’ll have to calibrate daily before the start of office hours by pointing the tonometer straight down, straight up, and waiting for the digital readout to affirm that the device is calibrated.

Remember, as you disinfect and calibrate your tonometer, make sure you have all the necessary ophthalmic supplies in stock. Automated Ophthalmics is your leading ophthalmic equipment supplier, specializing in latex tip covers for your tonometers, including the popular Reichert Tono-Pen, which makes both disinfection and calibration simpler for eye care professionals.