Frequently Asked Questions

What is Cidex® OPA and can it be used in TonoWash?

Cidex® OPA, unlike diluted bleach, alcohol, or 3% hydrogen peroxide, is categorized as a true High Level Disinfectant for semi-critical medical devices1. The product brochure states "Direct contact with eyes may cause irritation." Having a ph of 7.5, it is non-caustic (undiluted bleach has a ph of 12). Haag Streit is now listing Cidex Opa as one of the four disinfectants recommended in the US (Hydrogen Peroxide H2O2 3% , Sodium Hypochloride NaOCl Bleach, Cidex® OPA, and Rapicide® OPA/28)2.

Cidex Opa can be used in the TonoWash, however, it does require a 12 minute soaking time. All TonoWash purchased after October 15, 2021 are programmed with this optional setting. If you purchased a TonoWash before 10/15/2021, we would be happy to reprogram it for a nominal fee. This will be need to be performed at the factory, and will be expedited. You can order this by selecting the "12 minute programming update" on the Tonowash Buy Now page.


What is the CATS tonometer tip, and can it be disinfected in the TonoWash?

The CATS® Tonometer Prism features a unique, patented, dual-curved surface design that successfully reduces measurement errors caused by corneal biomechanics, corneal thickness, and tear film1.

TonoWash will soon be able to disinfect the CATS® Tonometer Prism with the same ease and efficiency as that clinics expect for the Goldmann Prism. We would be happy to notify as soon as this option becomes available. Select CATS notification on the Buy Now page.


What are the latest Joint Commission, CDC, and AAO recommendations regarding the disinfection of tonometer tips, and how can TonoWash™ be used to help comply with these recommendations?

The recommendations from the May 2019 update of CDC guidelines1,2, the AAO review article3, and the Joint Commission4 are somewhat confusing and contradictory. These references all suggest that 10:1 bleach may be superior to 3% hydrogen peroxide. Please note that many clinics express great reluctance to use bleach because of its caustic nature, and continue to use peroxide. Our interpretation of the above references suggest that the following steps be considered:

  1. Wipe clean the tonometer tip.
  2. Use 10:1 bleach in the TonoWash for 5-10 minutes (setting #2 of TonoWash)
  3. Rinse in the TonoWash water baths for a total of 5-10 minutes (setting #2 of TonoWash)
  4. A final rinse under tap water before placing on the tonometer
  5. Frequent inspection of the tonometer tip at the slit lamp to look for any cracks or damage

1. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008; Update: May 2019
2. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 Update: May 2019
3. Disinfection of Tonometers: A Report by the American Academy of Ophthalmology. Ophthalmology. 2017 Dec;124(12):1867-1875. doi: 10.1016/j.ophtha.2017.05.033. Epub 2017 Jul 11
4. Quick Safety 49 Disinfection of tonometers and other ophthalmology devices May 21, 2019

How do you fill the peroxide and water baths?

The peroxide bath (Fig. A) and the double water bath (Fig. B) easily slide out from the side of the TonoWashTM. Fill lines are easily visible inside each bath (Fig. C and Fig. D). After the baths are filled, they are then re-inserted into the TonoWashTM, and snap back into position.

What type of batteries are needed, and how often will the batteries need to be changed?

The TonoWash™ ships with two AA batteries pre-installed, as well as two spare AA batteries. The estimated battery life is from 6 months to a year, depending on the number of patients seen each day. There is no need to turn the TonoWashTM on and off each day, since it automatically switches to a power saving sleep mode when not in use. The batteries are easily assessable from underneath (Fig. E).

How many should I buy?

The most efficient set-up is to have one TonoWashTM and two tonometer tips in each exam room.  This way, one tonometer tip can be in use, while the other tip is being disinfected in the TonoWashTM.  The staff can easily exchange the tips while readying the room for the next patient.

What safeguards are built into the TonoWash™

Safety and reliability was the first priority in every step of the engineering and design of the TonoWashTM.  The “double dunk” ensures a complete rinsing of the peroxide every time.  The baths are designed so that there can be no confusion between the peroxide and the water baths.  In addition, the TonoWashTM will not allow the baths to be inserted in the wrong position or order by mistake.  Between cycles, all of the baths are kept covered, to help prevent any splashes or spills.  In the extremely unlikely chance of a malfunction, multiple safeguards are also built into the software.  An warning light will flash if the tonometer tip spends an insufficient amount of time in the peroxide bath, or in either of the water baths. A low battery warning light will flash well in advance of the critical time to change the battery.  The software will even prevent the TonoWashTM from starting a new cycle if there is insufficient battery charge to complete the cycle.

How long is the warranty, and what does it cover?

The warranty covers defects in material or workmanship for a period of one year from the date of purchase.

What is the 30-day money back guarantee?

We are so sure that you will find the TonoWashTM an amazing asset to your practice that we want you to try it risk free.  If you are not completely satisfied, return it for a full refund.

Can I buy the TonoWash™ through independent distributers or vendors?

No.  TonoWash™ is sold exclusively through

We prefer to soak the tonometer tip for 10 minutes. Can the TonoWash perform a 10 minute soak?

The TonoWash allows the customer to easily change the setting from a 5 minute soak to a 10 minute soak.

We currently use 1:10 diluted bleach as the disinfection solution. Can the TonoWash use bleach?

The CDC recommends that the tonometer tips can be disinfected for 5-10 minutes with either 3% hydrogen peroxide or 5000 ppm chlorine (bleach diluted 1:10).  Although the TonoWash was designed for use with peroxide, it should be noted that the plastic in TonoWash is very similar in chemical resistance to bleach as the plastic of the bleach bottle.  Therefore, no significant corrosion should be expected.  We would, however, recommend a quick final rinse and drying for safety.

Is there a volume discount or promotional discount?

TonoWash frequently offers volume and promotional discounts.  Please contact us by phone or email for further information.

How long does the entire cleaning cycle take?

The tonometer tip soaks in the peroxide bath for exactly 5 minutes.  It then rinses in the first water bath for 10 seconds, and in the second water bath for 10 seconds.  The entire cleaning cycle takes about 5 1/2 minutes.

Is there a special peroxide solution that I have to buy?

The TonoWash uses ordinary off-the-shelf 3% hydrogen peroxide found at supermarkets and drugstores.

Where is the TonoWash currently in use?

The TonoWash is now used at teaching hospitals, military hospitals, and both small and large private clinics throughout the United States and Canada.