12.2 Core Workflows and Decision Points
Key Takeaways
- Standard precautions — hand hygiene before and after every patient — are the single most tested infection-control behavior.
- Goldmann applanation tonometer tips are disinfected by soaking in 1:10 household bleach (sodium hypochlorite) or 3% hydrogen peroxide for 5–10 minutes, then rinsing and drying before reuse.
- Sodium hypochlorite (dilute bleach) is the agent of choice against adenovirus and HSV, the organisms behind clinic outbreaks; alcohol wipes alone are inadequate against non-enveloped adenovirus.
- Disposable tonometer tips and single-use diagnostic lenses eliminate the cross-contamination risk for high-suspicion contagious cases.
12.2 Core Workflows and Decision Points
Infection-control questions on the COA exam test procedures, not theory. The examiner wants to know whether you would actually break the chain of transmission at the right step.
The chain of infection
Transmission requires six links: a pathogen, a reservoir (an infected eye, a contaminated bottle), a portal of exit, a mode of transmission, a portal of entry (the next patient's eye), and a susceptible host. The COA's job is to break the weakest links — mode of transmission and portals — through hand hygiene and instrument disinfection. Memorize the chain; questions often ask which intervention "breaks the chain" most effectively, and the answer is almost always hand hygiene.
Hand hygiene — the most tested behavior
Perform hand hygiene before and after every patient contact, before donning and after removing gloves, and after touching any contaminated surface. Alcohol-based hand rub (60–95% alcohol) is acceptable for visibly clean hands; soap and water is mandatory when hands are visibly soiled and after exposure to a patient with suspected adenoviral conjunctivitis, because alcohol is less reliable against non-enveloped viruses. Gloves do not replace hand hygiene — a frequent distractor.
Instrument disinfection vs. sterilization
- Disinfection removes most pathogens from semi-critical items (tonometer tips, diagnostic contact lenses) that touch mucous membranes but do not enter sterile tissue.
- Sterilization destroys all microbial life — required for critical items (surgical and lacrimal instruments) that penetrate tissue; achieved with steam autoclave.
Tonometer-tip disinfection (high-yield)
The American Academy of Ophthalmology guidance for Goldmann applanation tonometer tips:
| Step | Detail |
|---|---|
| Agent | 1:10 dilution of household bleach (0.5% sodium hypochlorite) or 3% hydrogen peroxide |
| Soak time | 5–10 minutes of immersion of the tip |
| Rinse | Thoroughly rinse with water/saline after soaking — residual bleach causes corneal toxicity |
| Dry | Air-dry before reuse; reseat and verify the tip is intact |
| Best for | Adenovirus and HSV — the organisms behind clinic outbreaks |
Alcohol wipes alone are inadequate against non-enveloped adenovirus, the cause of epidemic keratoconjunctivitis (EKC). When contagious infection is strongly suspected, the safest workflow is a disposable tonometer tip or single-use lens — it removes the disinfection-failure risk entirely.
Medication and bottle hygiene
Never let a dropper tip touch the eye, lashes, or fingers — it contaminates the entire bottle. Use single-dose units for any patient with active infection, and never share a multi-dose bottle between an infected and a non-infected eye or patient.
Personal protective equipment and isolation
Standard precautions treat every patient as potentially infectious. Gloves are worn for any contact with the eye, drainage, or mucous membranes; eye protection and a mask are added when splash is possible (irrigation, lacrimal procedures). For a suspected adenoviral EKC case, the practical workflow is contact-precaution-style isolation: dedicate or disposable instruments, wipe high-touch surfaces, and dispose of gloves before touching clean equipment. Remember the correct doffing order — remove gloves first, then perform hand hygiene — because the glove exterior is the most contaminated surface.
Disinfectant levels at a glance
The exam expects you to match the level of decontamination to the item's risk category (the Spaulding classification).
| Item category | Definition | Required process | Ophthalmic example |
|---|---|---|---|
| Critical | Enters sterile tissue | Sterilization (autoclave) | Surgical blades, lacrimal probes |
| Semi-critical | Touches mucous membranes | High-level disinfection | Tonometer tip, diagnostic gonio lens |
| Non-critical | Touches intact skin | Low-level disinfection | Slit-lamp chinrest, occluder |
Cleaning before disinfecting
A step candidates skip: cleaning precedes disinfection. Organic debris (tears, mucus, blood) shields microbes and inactivates disinfectants, so an instrument must be wiped or rinsed free of visible soil before it is soaked in bleach or peroxide. Disinfecting a dirty tip is a false sense of safety. Likewise, after the bleach soak the rinse step is not optional — residual sodium hypochlorite is directly toxic to the corneal epithelium and will cause a chemical keratitis at the next visit. Clean, disinfect, rinse, dry: that four-step order is itself testable.
Specimen collection basics
The COA may assist the physician in obtaining cultures, so know the order. Cultures and conjunctival/corneal scrapings are taken before instilling antibiotics, because antibiotic exposure suppresses growth and yields a false-negative culture. A topical anesthetic without preservative is generally preferred before a corneal scraping so the preservative does not inhibit the organism. Specimens go onto the correct media — blood and chocolate agar for common bacteria, Sabouraud agar for fungi — and to the lab promptly.
The single most testable rule: collect the specimen first, treat second, and label the sample with site and laterality so the result is traceable to the right eye.
Reporting a suspected outbreak
If several patients from the same clinic develop the same red-eye picture in a short window, the COA's role is to escalate, not diagnose: notify the supervising ophthalmist and follow the practice's infection-control plan. An adenoviral EKC cluster may require temporarily removing shared equipment from service and switching to disposables until the source is controlled.
A patient with suspected epidemic keratoconjunctivitis (adenovirus) was just examined. Reusable Goldmann tonometer tips must be reused later that day. Which disinfection step is most appropriate?