Abstract
Purpose: :
Silver-infused contact lenses (CLs) may provide benefits to CL wearers by reducing adherence of potential pathogens to CL surfaces; however, they have the potential to modify the normal ocular biota during CL wear. This study investigated the effect of silver-infused silicone hydrogel CLs on conjunctival flora over six months of daily wear.
Methods: :
A prospective, randomised, double-masked, contralateral study was conducted. Sixty subjects were randomly assigned to wear silver-infused (galyfilcon A with incorporated silver ions, test) and standard (galyfilcon A, control) silicone hydrogel CLs on a contralateral basis for six months of daily wear. Prior to assignment of the test and control CLs, all subjects were fitted with etafilcon A daily disposable CLs for a one week wear-in period. Conjunctival flora were cultured at screening/pre-baseline (with subjects’ habitual CLs), baseline (after daily disposable wear) and four weeks, three and six months following commencement of test and control CL wear, using sterile calcium alginate swabs moistened with sterile unpreserved 0.9% saline.
Results: :
There were no statistically significant differences between the conjunctivae of test and control eyes in the incidence of positive cultures (p>0.05), culture classification grades (p>0.05), levels of microorganisms (p>0.05) or the numbers of different types of microorganisms isolated (p>0.05). Wear of the test CLs did not promote any fungal or yeast colonisation of the conjunctivae. The microorganisms most frequently isolated from the conjunctivae were Gram-positive bacteria considered to be part of the normal ocular flora, including Coagulase-negative Staphylococci, Propionibacterium spp, Corynebacterium spp, and Micrococcus spp.
Conclusions: :
Wear of the silver-infused CLs did not result in any statistically or clinically significant alterations to the ocular biota over six months of daily wear.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00531375
Keywords: contact lens • conjunctiva • microbial pathogenesis: clinical studies