CONTACT LENS CARE & COMPLIANCE
REDUCING CONTACT LENS CASE CONTAMINATION
ANDREW D. PUCKER, OD, PHD, FAAO
Contact lens cases are integral for maintaining daily wear contact lenses. However, up to 80% of all contact lens wearers are using microbially contaminated cases (Wu, Zhu, Harmis et al, 2010; Panthi et al, 2014). Case contamination happens regardless of the case type (two-well cases ≅ stand-up basket cases), and it can happen via a number of mechanisms (Wu, Zhu, Harmis et al, 2010; Vijay et al, 2015).
While many patients do not perceive case contamination as a problem (Hickson-Curran et al, 2011), it could potentially lead to vision-threatening conditions, such as microbial keratitis (Stapleton et al, 2012). Combating contact lens case contamination starts with understanding good clinical practices and conveying this information to our contact lens-wearing patients.
Healthy Case Habits
Case Age The median time interval for contact lens case replacement is every four to six months (Hickson-Curran et al, 2011), which is a major problem because case age has been associated with case contamination (Wu, Zhu, Harmis et al, 2010). The literature does not offer a definitive age at which a contact lens case should be discarded (Panthi et al, 2014). Lakkis et al (2009) determined that contact lens cases can become contaminated in less than one week. Also, case contamination is four times higher, and keratitis is more likely, if patients discard their cases less frequently than every three months, which suggests that patients should discard their contact lens cases at least every three months if not more frequently (Panthi et al, 2009; Stapleton et al, 2012).
Hand Washing Washing hands with soap and water before handling a contact lens case can significantly reduce case contamination compared to not washing hands or to rinsing hands with just tap water (Wu et al, 2015). With that said, patients should also avoid exposing a lens case directly to tap water because tap water is thought to be the primary source of Acanthamoeba contamination (Hickson-Curran et al, 2011).
Case Cleaning Regimen In addition to replacing lens cases regularly, Vijay et al (2015) compared 10 different regimens for cleaning contact lens cases. They found that rinsing cases with contact lens care solution, wiping them with tissue, and air-drying them face down was the most effective means for removing bacterial biofilms.
Storage Locations/Position Patients most commonly (79%) store their cases in the bathroom (Wu et al, 2015). While this is not necessarily a bad storage location, caution should be taken when contact lens cases are stored there. Specifically, cases have lower levels of contamination if they are air-dried (Wu et al, 2015); however, if they are air-dried facing up in the bathroom (moist environment), they are more likely to be contaminated than if they were air-dried in the bedroom (dry environment) (Wu, Zhu, Willcox et al, 2010). In addition, when cases were air-dried face down, there was no difference between the two locations (Wu, Zhu, Willcox et al, 2010).
Established contact lens wearers tend to have higher levels of case contamination compared to new contact lens wearers (Wu et al, 2015), and overall, only a small portion of patients (26%) clean their lens cases daily (Hickson-Curran et al, 2011). Furthermore, when patients do clean their contact lens cases, they are likely not following many of the good practices outlined above, which suggests that they may have simply forgotten the details of case care or their eyecare practitioner may never have taught them the proper methods.
Lens case care instructions are just as important as contact lens care instructions because one can easily contaminate the other. It is our job as eyecare professionals to help our lens-wearing patients avoid any potential microbial events by making them aware of this information. CLS
For references, please visit www.clspectrum.com/references and click on document #250.
Dr. Pucker earned his OD and PhD degrees from The Ohio State University. He is currently an assistant professor at the University of Alabama at Birmingham. He has also received research funding from Johnson & Johnson Vision Care. You can reach him at firstname.lastname@example.org.