Infection control is a major focus of the COA exam's Assisting with Interventions and Procedures domain. As the person who most frequently interacts with equipment between patients -- cleaning the slit lamp, disinfecting tonometer prisms, setting up for the next exam -- the COA is a critical line of defense against healthcare-associated infections.
Ophthalmology presents unique infection control challenges. Many instruments contact mucous membranes (conjunctiva, cornea) rather than intact skin, placing them in the semi-critical category requiring high-level disinfection. The eye is also highly susceptible to infection from organisms that would cause no harm on intact skin. An adenoviral EKC outbreak in a busy practice can affect dozens of patients before it is recognized and controlled.
This guide covers standard precautions, the Spaulding classification system, specific protocols for common ophthalmic equipment, outbreak management for EKC, and OSHA requirements. Each of these is directly testable on the COA exam.
Standard Precautions and Hand Hygiene
Standard precautions (formerly called universal precautions) treat all patients as potentially infectious for bloodborne and other pathogens. In ophthalmology, this means hand hygiene before and after every patient contact, use of gloves when contact with mucous membranes or body fluids is anticipated, and eye protection when splash risk exists (e.g., removing an eye patch, irrigating an eye).
CDC 5 Moments for Hand Hygiene
Moment 1
Before touching a patient
Moment 2
Before a clean/aseptic procedure (instilling drops, tonometry)
Moment 3
After body fluid exposure risk (removing gloves)
Moment 4
After touching a patient
Moment 5
After touching the patient's surroundings (equipment, chair, instruments)
Hand Hygiene Method
Use alcohol-based hand rub for routine decontamination (faster and more effective than soap for most organisms). Use soap and water when hands are visibly soiled, after using the restroom, or after potential contact with C. difficile spores or norovirus (alcohol is not sporicidal). Friction is the key active mechanism for both methods.
Spaulding Classification Applied to Ophthalmology
The Spaulding classification system provides the framework for determining how each piece of equipment must be processed. Choosing the wrong level -- using low-level disinfection on a semi-critical item, for example -- is a patient safety violation regardless of how efficient it is.
Critical Items
STERILIZATION REQUIREDContact sterile tissue or vascular system. Any residual microorganism could cause infection.
Ophthalmic examples: Surgical instruments (iris scissors, forceps, cannulas), irrigating solutions used intraocularly, needles, IOL injector cartridges. Must be sterilized by autoclaving (steam under pressure), ethylene oxide gas, or hydrogen peroxide gas plasma.
Semi-Critical Items
HIGH-LEVEL DISINFECTIONContact mucous membranes or non-intact skin. Must kill all microorganisms except high numbers of bacterial spores.
Ophthalmic examples: Goldmann tonometer prisms, goniolenses (3-mirror, 4-mirror), fundus contact lenses (Volk SuperField, etc.), indirect ophthalmoscope lenses that touch the eye, trial contact lenses, speculum and retractors used in OR. High-level disinfection agents: glutaraldehyde (Cidex), hydrogen peroxide 3%, sodium hypochlorite 1:10 dilution, 70% IPA (with adequate contact time).
Non-Critical Items
LOW-LEVEL DISINFECTIONContact intact skin only. Must kill vegetative bacteria, most viruses, and fungi but not necessarily mycobacteria or spores.
Ophthalmic examples: Exam chairs, slit lamp chin rests, forehead rests, trial frames, tonometer bodies (not prisms), visual acuity chart remotes, computer keyboards. Low-level disinfectants: quaternary ammonium compounds, 70% isopropyl alcohol wipes, EPA-registered hospital disinfectants.
Tonometer Disinfection Protocols
Tonometer tips are semi-critical items. They contact the corneal epithelium (a mucous membrane) and can transmit adenovirus, herpes simplex virus, hepatitis B, and theoretically prion diseases (CJD) if not properly disinfected. Multiple acceptable protocols exist; know the agent, concentration, and minimum contact time for each.
| Agent | Concentration | Contact Time | Notes |
|---|---|---|---|
| Isopropyl alcohol wipe | 70% | Wipe; 5 min air dry | Does NOT reliably kill adenovirus; minimal for HIV; fastest for routine use |
| Sodium hypochlorite (bleach) | 1:10 dilution (5,000 ppm) | 10 min soak | Kills adenovirus and HIV; rinse thoroughly; make fresh daily; can corrode metal |
| Hydrogen peroxide | 3% | 10 min soak | Effective broad-spectrum; rinse and dry after; less corrosive than bleach |
| UV light box | UV-C (253.7 nm) | Per device instructions | Effectiveness depends on device and exposure; must follow manufacturer protocol |
Critical Rinsing Step
After any chemical disinfection of a tonometer tip, thoroughly rinse with sterile water or sterile saline and allow to air dry before use. Residual bleach or hydrogen peroxide on the prism can cause corneal epithelial toxicity. This rinse step is as important as the disinfection itself.
EKC Outbreak Control: Epidemic Keratoconjunctivitis
Epidemic keratoconjunctivitis (EKC) is caused by adenovirus (serotypes 8, 19, and 37 most commonly). It is highly contagious, can survive on surfaces for weeks, and is resistant to routine alcohol disinfection. A single infected patient can spread the infection to multiple staff and other patients if protocols are not followed.
EKC Control Protocol
- 1.Cohorting: Schedule suspected EKC patients at the end of the day or in a dedicated room. Use dedicated equipment that stays in that room.
- 2.Disinfection: All surfaces that contacted the patient or were in the exam room must be disinfected with 1:10 bleach solution (sodium hypochlorite 5,000 ppm), not alcohol. Contact time minimum 10 minutes.
- 3.Tonometry: Avoid Goldmann tonometry if possible; use a single-use disposable tonometer tip cover (Tonoshield), or use a non-contact tonometer (NCT/air-puff) for suspects. Defer tonometry if not clinically essential.
- 4.Hand hygiene: Strict hand washing with soap and water (not just ABHR) after any contact with a suspected EKC patient, since some adenovirus strains are partially resistant to alcohol.
- 5.Staff with EKC: Staff members with active EKC symptoms (watery discharge, follicular conjunctivitis, pseudomembrane) must be excluded from patient contact until cleared by a physician, typically at least 3 days after onset.
- 6.Patient education: Warn affected patients about transmission: avoid touching eyes, do not share towels or pillowcases, wash hands frequently, avoid close contact with family members.
Practice COA Infection Control Questions
Infection control, sterilization, and safety protocols appear on the COA exam. Build confidence with real exam-style questions and detailed AI explanations.
Chemical Hazards: Formaldehyde and Glutaraldehyde
Glutaraldehyde (brand name Cidex) is a high-level disinfectant used for semi-critical items. It is effective against bacteria, fungi, viruses, and mycobacteria when used at proper concentrations (2% activated glutaraldehyde) for the required contact time (20-45 minutes depending on product formulation). However, it is a known sensitizer and irritant -- skin, eye, and respiratory tract irritation are well-documented occupational hazards.
Glutaraldehyde OSHA Requirements
- Impervious gloves and eye protection required
- Adequate ventilation (or respiratory protection if above ceiling limit)
- Safety Data Sheet (SDS) must be accessible
- Containers must be labeled with chemical hazard information
- Employees must be trained on hazards, PPE, and emergency procedures
- Spill cleanup procedures must be established
Waste Management
- Regulated medical waste (RMW): blood-soaked materials, pathological specimens
- Sharps containers are classified as RMW regardless of volume
- Must be disposed through licensed medical waste hauler
- Glutaraldehyde: dispose per SDS and local regulations; not for drain disposal above regulated limits
- Bleach solutions: can be disposed down drain after neutralization
HIPAA in Clinical Photography
Fundus photographs, external photographs, and slit lamp images are protected health information (PHI) under HIPAA. Images that identify a patient -- those showing the face or other identifying features -- require the same protections as other medical records.
Clinical photography rules for the COA: Obtain written consent before taking external photographs that include facial features. Never use personal mobile phones to photograph patients without explicit consent and institutional policy allowing it. Store images only in the approved EHR or PACS system. Do not share images on personal devices or social media even without patient names -- the images themselves can be identifying. Images requested for educational purposes or publication require a separate HIPAA authorization form.