Worldwide, it is estimated that there are 140 million contact lens wearers who have chosen this solution for both refractive and cosmetic purposes. In addition to the numerous advantages of contact lenses, however, there are potential risks of eye infection, essentially determined by inadequate lens handling and maintenance practices.
How does an eye infection from contact lenses arise?
Contact lenses not properly cleaned and maintained when worn, alter the natural environment of the eye by introducing on the ocular surface a load of micro-organisms from contaminated hands, lens care solutions or the lenses themselves.
The lenses also interfere with the protective function exerted by the mucin layer, which offers natural resistance to bacterial adhesion, and hinder the release of antimicrobial factors.
During insertion, removal and cleaning, contact lenses are touched with fingertips and palms, which in turn touch everything around us, including the ubiquitous mobile phone.
The role of mobile phones
I smartphone touchscreens are known carriers of pathogens in the clinical environmentbut despite the ever-growing number of smartphone users, little is known about the bacterial contamination of touchscreens in a non-clinical environment.
A study, recently published in Contact Lens and Anterior Eye, investigated the presence of bacterial pathogens on the conjunctiva, on mobile phones and in contact lens casesin order to highlight possible correlations between the bacteria isolated from the 3 sites.
The authors analysed 189 swabs from conjunctiva, mobile phones and lens cases taken from 63 university students who wore contact lenses.
The team of researchers isolated 9 bacterial species: Staphylococcus. aureus, Streptococcus pyogenes, Enterococcus faecalis, Shigella dysentery, Pseudomonas aeruginosa, Proteus mirabilis, Citrobacter spp, Klebsiella pneumoniae and Escherichia coli. Nine samples (26%) from mobile phones and seven (21%) from conjunctiva were contaminated with five different bacterial species. The highest level of contamination was detected in the housings for lens preservation in which 18 (52%) bacterial isolates were isolated.
The study found the same pathogenic bacteria on conjunctiva, smartphone screens and lens storage cases.
The smartphone represent, therefore, a a vehicle for transmitting pathogenic bacteria to the eyes and thus a potential eye health risk for contact lens wearers.
The study emphasises the need to increase awareness of the good hygiene practices of hands and the storage and handling of contact lenses, as a means of preventing the risks of infection that may be associated with contact lens wear.
Source
Al Momani Waleed et al. Antimicrobial susceptibility of bacterial isolates from the conjunctiva, storage cases and mobile phones of university students using contact lenses. Contact Lens and Anterior Eye, 2019.
Dr. Carmelo Chines
Direttore responsabile
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