What is the difference between standard precautions and transmission-based precautions?

Standard precautions are applied to every patient encounter regardless of diagnosis, treating all body fluids as potentially infectious. Transmission-based precautions are additional measures added on top of standard precautions for patients with known or suspected conditions that pose higher transmission risks, such as contact precautions for adenoviral conjunctivitis or airborne precautions for tuberculosis.

Why are gloves not a substitute for hand hygiene?

Gloves can have micro-perforations that are invisible to the eye, allowing fluid to penetrate. Pathogens can also contaminate the outer surface of gloves during use. When gloves are removed, hands can be contaminated through improper doffing technique. Hand hygiene after glove removal eliminates residual contamination from any of these pathways. Gloves and hand hygiene are complementary, not interchangeable.

How should tonometer prisms be disinfected between patients?

Tonometer prisms require specific disinfection to avoid patient-to-patient transmission of pathogens including adenovirus and HSV. Common methods include: wiping with isopropyl alcohol (70%) and allowing adequate contact time; soaking in 1:10 diluted sodium hypochlorite (bleach) solution for 5-10 minutes; or using commercial hydrogen peroxide-based disinfectants. The method depends on the prism material. The prism must be rinsed and dried before use on the next patient.

What is the correct hand hygiene technique with alcohol-based hand rub?

Apply enough alcohol-based hand rub to cover all surfaces of the hands. Rub hands together palm-to-palm, then palm over dorsum (back) of each hand, then interlaced fingers, then backs of fingers, then rotational rubbing of thumbs, then fingertips into palm. Continue rubbing until the product is completely dry, which typically takes 20-30 seconds. The product must remain in contact with the skin throughout this process to be effective.

Infection Control & Standard Precautions in Optometry

The Foundation: Standard Precautions

Standard precautions are the minimum level of infection prevention practices that must be applied to every patient encounter, regardless of the patient's known or suspected diagnosis. They are based on the principle that any patient can be a source of infectious material, whether or not they have an identifiable infection. In other words, you treat every patient as if their blood, tears, and body fluids could be infectious.

Standard precautions were developed and are maintained by the Centers for Disease Control and Prevention (CDC) and are required in all healthcare settings, including optometry offices. They encompass hand hygiene, personal protective equipment, equipment cleaning and disinfection, respiratory hygiene, and safe injection practices.

Hand Hygiene

Hand hygiene is the single most effective intervention for preventing the spread of healthcare-associated infections. In an optometric setting, you perform hand hygiene:

Before and after every patient contact.
Before performing any procedure (including instilling drops).
After removing gloves (gloves are not a substitute for hand hygiene).
After touching contaminated surfaces or equipment.
After touching your own face or adjusting personal protective equipment.

Proper techniques:

Soap and water: Required for visibly soiled hands and for Clostridium difficile (which alcohol does not kill). Wash for at least 20 seconds.
Alcohol-based hand rub (ABHR): Sufficient for most situations. Apply enough to cover all surfaces of the hands and rub until dry (typically 20-30 seconds).

Remove rings and watches before patient care activities. These harbor bacteria in the grooves and crevices where soap or sanitizer cannot reach effectively. This is a simple habit change that significantly reduces hand contamination.

Personal Protective Equipment (PPE)

Personal protective equipment creates a physical barrier between the healthcare worker and potentially infectious material. In optometry, PPE use is situational:

PPE Item	When to Use in Optometry
Gloves	When contact with tears, discharge, blood, or mucous membranes is expected (e.g., eyelid procedures, foreign body removal)
Mask	When respiratory droplets are a concern, or when working within 1 meter of a patient with respiratory illness
Eye protection (goggles/face shield)	When splash of fluids is possible (irrigation, surgical assist)
Gown	When clothing contamination is possible

PPE must be donned (put on) before patient contact and doffed (removed) carefully after contact, taking care not to self-contaminate during removal. Gloves should be changed between patients and never reused.

Equipment Disinfection Between Patients

In an optometric office, many instruments and surfaces come into contact with multiple patients each day. Failure to clean and disinfect these surfaces provides a direct pathway for pathogen transmission.

Key items requiring disinfection between patients:

Slit lamp chin rest and headband
Phoropter face shields and handles
Tonometer tips (especially important after contact procedures)
Trial frame and trial lenses
Examination chair headrest
Any contact lenses or contact instruments used in procedures

Products used for disinfection must be appropriate for the organism of concern. For most surfaces, an EPA-registered hospital-grade disinfectant wipe is sufficient. Tonometer prisms require cleaning and disinfection specific to the prism material (some are soaked in dilute bleach or hydrogen peroxide).

Simply wiping equipment with a dry cloth or tissue is not disinfection. You need a chemical disinfecting agent that has been approved for that surface and adequate contact time (following the manufacturer's dwell time instructions). Wipe the surface, let it remain wet for the specified time, then allow to dry.

Respiratory Hygiene and Cough Etiquette

Patients with respiratory symptoms (cough, sneeze, runny nose) present an inhalation risk, particularly during the COVID-19 era when respiratory precautions became more prominent. Standard guidance includes:

Ask patients to wear a mask if they have respiratory symptoms.
Provide tissues and waste containers at reception areas.
Maintain distance from patients who are coughing or sneezing when possible during history-taking.

Transmission-Based Precautions

When standard precautions are insufficient for patients with known or suspected highly communicable conditions, additional transmission-based precautions are added:

Contact precautions: For patients with conditions spread by direct skin contact (e.g., severe adenoviral conjunctivitis, impetigo). Gown and gloves for all contact.
Droplet precautions: For respiratory pathogens spread by large droplets. Surgical mask within 1 meter of the patient.
Airborne precautions: For pathogens that spread by tiny aerosol particles (e.g., tuberculosis, measles). Requires N95 respirator and negative pressure rooms (typically not applicable in routine optometry).

Key Takeaways

Standard precautions apply to every patient, every time, regardless of diagnosis.
Hand hygiene is the most effective single infection control measure.
PPE (gloves, masks, eye protection) is used based on the anticipated exposure risk.
Equipment contact surfaces must be disinfected between every patient with an EPA-registered disinfectant.
Transmission-based precautions are layered on top of standard precautions for high-risk conditions.