Contact Lens Use and Pseudomonas Infection Risk
Yes, contact lens users are definitively at increased risk for Pseudomonas infections, with Pseudomonas aeruginosa being the most commonly isolated organism in contact lens-associated microbial keratitis. 1, 2
Evidence for Increased Risk
Contact lens wear is the most common risk factor for bacterial keratitis overall, with Pseudomonas aeruginosa specifically identified as the predominant pathogen in this population. 1 The American Academy of Ophthalmology guidelines explicitly state that Pseudomonas aeruginosa became a frequently identified pathogen when soft contact lenses were introduced for extended wear, and it remains the most commonly isolated organism in microbial keratitis associated with contact lens use. 1
Magnitude of Risk by Wear Pattern
The risk varies dramatically based on how lenses are worn:
- Extended/overnight wear increases risk 10-15 times compared to daily wear 1
- Annualized incidence is 5 times higher for extended-wear users (21 per 10,000) versus daily-wear users (4 per 10,000) 1
- Extended-wear users have an incidence of 2.52 per 10,000 versus 0.52 per 10,000 for daily disposable lens users 3
- The pattern of wear (overnight vs. daily) is the overriding risk factor, not the type of lens (disposable vs. nondisposable) 1
Mechanism of Pseudomonas Infection
Pseudomonas aeruginosa adheres readily to contact lens deposits, which accumulate as duration of use increases. 1 This creates a biofilm environment that facilitates bacterial colonization and subsequent corneal invasion when the cornea's natural defense mechanisms are compromised by lens wear. 1
Specific High-Risk Behaviors
Contact lens users face particularly elevated Pseudomonas risk with:
- Overnight wear or overnight orthokeratology 1
- Water exposure: swimming, hot tubs, showering while wearing lenses 1, 2
- Tap water contact: rinsing lenses or cases with tap water 1
- Poor hygiene: inadequate disinfection, topping off solutions, contaminated lens cases 1
- Overwear beyond FDA-approved replacement schedules 1
Clinical Significance
Bacterial keratitis is the most serious complication of contact lens wear and can lead to visual loss even if properly treated. 1, 2 Recent data shows Pseudomonas aeruginosa was isolated in 3.4-19.5% of contaminated contact lens samples from asymptomatic users, indicating subclinical colonization is common. 4, 5 In symptomatic cases requiring hospitalization, Pseudomonas was the most frequently isolated microbe. 3, 6
Common Pitfalls
- Failing to recognize that even "approved" extended-wear lenses carry significantly elevated infection risk compared to daily wear 1
- Underestimating the importance of water avoidance—any water exposure (tap, bottled, or homemade saline) dramatically increases risk 1, 2, 7
- Assuming daily disposable lenses eliminate risk—while safest, they still carry infection risk if worn overnight or exposed to water 1, 3
- Not educating patients that lens cases are the most contaminated item (62% contamination rate), requiring replacement every 3 months minimum 4, 5, 2
Geographic Variation
While Pseudomonas is the dominant pathogen globally in contact lens-related keratitis, gram-negative organisms are more prevalent in the southern United States than northern regions, with south Florida having the highest rates. 1 However, this geographic variation does not diminish the overall association between contact lens use and Pseudomonas infection risk.