How should Goldmann tonometer tips be disinfected?

After use, wipe the tip to remove visible tear film and fluorescein. Soak in an approved disinfectant (dilute bleach, 70% alcohol, or 3% hydrogen peroxide) for the recommended contact time, typically 5-10 minutes. Rinse thoroughly with sterile water to remove chemical residue and allow to air dry on a clean surface. Never use abrasive cleaners that could damage the optical surfaces.

What surfaces need to be disinfected between patients?

All surfaces that patients touch or that come into contact with their face or eyes must be disinfected between patients. This includes the chin rest and forehead rest on the slit lamp, autorefractor, and phoropter; the slit lamp joystick and oculars; phoropter dials; tonometer tips; trial frame surfaces; and any other instrument surfaces patients contact during the examination.

Why is contact time important for disinfection?

Contact time is the duration the disinfectant must remain in wet contact with the surface to effectively kill pathogens. Simply spraying and immediately wiping off does not allow enough time for the chemical to destroy microorganisms. Each disinfectant product specifies a required contact time on its label, typically 1-3 minutes for surface wipes and 5-10 minutes for soaking solutions. Failing to observe adequate contact time leaves surfaces inadequately disinfected.

Equipment Disinfection in Ophthalmology: COA Exam Guide

Why Equipment Disinfection Matters

Ophthalmic instruments come into close contact with patients' eyes, faces, and tears during every examination. Without proper disinfection between patients, these instruments become vectors for transmitting infections, including bacterial conjunctivitis, viral keratoconjunctivitis, and even more serious pathogens. As a COA, maintaining equipment hygiene is part of your daily responsibility and a testable topic on your certification exam.

Principles of Disinfection

Disinfection is distinct from sterilization. Disinfection eliminates most pathogenic organisms from surfaces and instruments but does not kill all microbial forms (such as bacterial spores). Sterilization eliminates all microorganisms, including spores, and is required for instruments that penetrate sterile tissue.

For routine ophthalmic examination equipment, disinfection is the appropriate level of decontamination. The instruments used in standard pre-testing and examination touch intact skin or mucous membranes but do not penetrate tissue.

High-Touch Surfaces Between Patients

The following surfaces must be cleaned and disinfected between every patient encounter:

Equipment	Contact Surfaces	Disinfection Method
Slit lamp	Chin rest, forehead rest, joystick, oculars	Alcohol wipe or disinfectant wipe
Phoropter	Forehead rest, face shield, dials	Alcohol wipe or disinfectant wipe
Autorefractor/keratometer	Chin rest, forehead rest	Alcohol wipe or disinfectant wipe
Tonometer (applanation)	Tonometer tip/prism	Soak in dilute bleach, alcohol, or H2O2; rinse and dry
Trial frame/trial lenses	Frame surface, lens edges	Alcohol wipe
B-scan probe	Probe tip	Alcohol wipe; probe cover for each patient

The tonometer tip requires the most rigorous disinfection because it directly contacts the corneal surface. Accepted methods include soaking in dilute sodium hypochlorite (bleach), 70% isopropyl alcohol, or 3% hydrogen peroxide for the manufacturer-recommended contact time, followed by rinsing with sterile water and air drying.

Tonometer Tip Disinfection

The Goldmann applanation tonometer prism requires careful handling because it touches the corneal surface and tear film:

After use, wipe away visible tear film and fluorescein with a lint-free tissue
Soak the prism in the appropriate disinfectant for the recommended time (typically 5-10 minutes depending on the agent)
Rinse thoroughly with sterile water to remove any chemical residue
Allow to air dry on a clean, lint-free surface
Never use abrasive cleaners that could scratch the optical surfaces

Simply wiping the tonometer tip with an alcohol pad and immediately using it on the next patient. A quick wipe does not provide adequate contact time for disinfection. The disinfectant must remain in contact with the surface for the specified time to be effective against viral pathogens like adenovirus and herpes simplex.

Disinfectant Types

70% isopropyl alcohol: effective against most bacteria and many viruses; used for general surface cleaning
Dilute sodium hypochlorite (bleach): effective against a broad spectrum including adenovirus; used for tonometer tips and outbreak situations
Hydrogen peroxide (3%): alternative for tonometer disinfection
Quaternary ammonium compounds: used in commercial disinfectant wipes for general surfaces

Contact Time and Air Drying

Disinfection effectiveness depends on contact time, the duration the disinfectant remains in wet contact with the surface. Simply spraying and immediately wiping off is insufficient. Each disinfectant product has a labeled contact time (often 1-3 minutes for surface wipes, 5-10 minutes for soaking solutions). Allow surfaces to remain wet for the full contact time before wiping dry or allowing to air dry.

Handling During Outbreaks

During suspected viral conjunctivitis outbreaks (particularly adenoviral EKC), enhanced protocols include:

Disinfecting all surfaces the patient may have touched
Using disposable tonometer tips or Tono-Pen covers
Designating the patient to a specific exam room
Avoiding use of communal waiting areas when possible
Hand hygiene before and after every patient contact

Adenovirus is extremely hardy and can survive on dry surfaces for weeks. During an EKC outbreak, use dilute bleach solution (1:10 dilution of household bleach) on all exam room surfaces, including door handles, armrests, and counter tops, not just the instruments. Standard alcohol wipes may not fully eliminate adenovirus.

Key Takeaways

Disinfect all patient-contact surfaces between every patient encounter
Tonometer tips require soaking in disinfectant (not just wiping) with adequate contact time
Contact time is essential: the surface must remain wet with disinfectant for the labeled duration
Adenovirus survives on surfaces for weeks; use bleach solution during outbreaks
Air dry instruments after rinsing to prevent recontamination
Disinfection is sufficient for non-penetrating instruments; sterilization is for surgical instruments