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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 (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).
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.
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.
Contact 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.
Contact 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).
Contact 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 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.
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.
Infection control, sterilization, and safety protocols appear on the COA exam. Build confidence with real exam-style questions and detailed AI explanations.
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.
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.
OR role, sterile technique, instrument passing, and surgical protocols.
Pharmacology and clinical use of topical anesthetic agents in ophthalmology.
Technique, calibration, and infection control for Goldmann applanation tonometry.
Format, domains, eligibility, and registration for the COA exam.
The Spaulding classification categorizes medical instruments by infection risk to determine the required level of disinfection or sterilization. Critical items contact sterile tissue and require sterilization (surgical instruments, irrigation cannulas). Semi-critical items contact mucous membranes or non-intact skin and require high-level disinfection (tonometer prisms, contact lenses used for examination, goniolenses, fundus contact lenses). Non-critical items contact intact skin only and require low-level disinfection (exam chairs, slit lamp chin rests, trial frames). Applying the correct level prevents both under-disinfection (infection risk) and over-processing (instrument damage).
IJCAHPO and AAO guidelines accept several methods for Goldmann tonometer tip disinfection: (1) Wipe with 70% isopropyl alcohol and allow a 5-minute air dry -- this is the most common method but does not inactivate all organisms including adenovirus at 5 minutes. (2) Soak in 3% hydrogen peroxide for 10 minutes, then rinse and dry. (3) Soak in 1:10 sodium hypochlorite (household bleach diluted 1:10) for 10 minutes, then rinse -- effective against adenovirus and HIV. (4) UV light disinfection boxes require careful validation of exposure time. The key principle: after disinfection, thoroughly rinse with sterile water or saline to remove chemical residues that can damage corneal epithelium.
EKC is caused by adenovirus (most commonly serotypes 8, 19, 37) and is highly contagious through direct contact and fomite transmission. Control measures: (1) Suspect cases should be seen at the end of the day or in a dedicated room. (2) Use disposable equipment where possible; disinfect all reusable contact surfaces with 1:10 bleach solution (more effective than alcohol for non-enveloped adenovirus). (3) Strict hand hygiene before and after every patient contact. (4) Staff members with active EKC should be excluded from patient contact for at least 3 days after symptom onset or until a physician clears them. (5) Warn the patient that family members are at risk through shared towels, pillowcases, and hand contact.
The CDC 5 Moments are: (1) Before touching a patient. (2) Before a clean or aseptic procedure (e.g., instilling drops, tonometry). (3) After body fluid exposure risk (e.g., removing gloves after touching discharge, blood, or mucus). (4) After touching a patient. (5) After touching the patient's surroundings (equipment, exam chair, bedside). All five apply directly to ophthalmology clinical practice. Use alcohol-based hand rub for routine decontamination; wash with soap and water when hands are visibly soiled or after contact with a patient with suspected norovirus or C. difficile.
OSHA requires medical surveillance when employee exposure to formaldehyde exceeds 0.5 ppm as an 8-hour time-weighted average (the action level) or 1 ppm short-term. For glutaraldehyde, OSHA uses the hazard communication standard rather than a substance-specific standard, but it is still classified as a hazardous chemical requiring proper labeling, SDS availability, and use of gloves and eye protection. In ophthalmic settings, glutaraldehyde (Cidex) may be used for instrument sterilization and requires adequate ventilation, PPE, and proper disposal as a regulated medical waste. Employees must receive training on chemical hazards when first assigned to a job involving these chemicals.