One method of identifying which organisms are involved in cases of corneal eye infections is to look at the cultures of contact lenses, according to an article in Archives of Ophthalmology (JAMA/Archives), September issue.
The authors of the articles say “Contact lens wear is associated with a significant risk of microbial keratitis [corneal eye infection] leading to severe sight-threatening complications. Microbial keratitis has been seen in all types of lenses, including rigid gas-permeable lenses, hard or poly-methylmethacrylate lenses and high-and-low-oxygen transmissibility soft lenses, as well as with all modes of wear, including daily wear, extended wear, therapeutic wear and continuous wear.”
Soft contact lenses are more likely to trigger infections than other types of lenses, the authors write.
Sujata Das, M.S., F.R.C.S., of the Center for Eye Research Australia, University of Melbourne and Royal Victorian Eye and Ear Hospital, Melbourne, Australia, and colleagues looked at the records of 49 patients who suffered from contact lens-related microbial keratitis. Their average age was 34. The study looked at the period January 2001 – December 2004. Their aim was to see what link there was between cultures of contact lenses and cultures of corneal scrapings. They factored in such variables as sex, symptoms, age, results and predisposition.
Of the 49 patients (98 eyes) there were 50 eyes with microbial keratitis. 34% (17) of corneal scrapings and 70% (35) of the contact lenses had organisms breeding on them. As far as 13 of the eyes were concerned, the organisms that were growing in the cultures taken from the contact lenses and corneal scraping were identical. Only two eyes had different organisms from the contact lenses. In just two eyes were corneal scrapings found to be culture positive, wrote the authors.
The most common organism found in the corneal scrapings as well as the contact lenses was Serratia Marcescens.
The writers conclude “Our study highlights the fact that contact lens culture may help in identification of the causative organism in many cases of contact lens-related microbial keratitis. Also, contact lens culture may give a clue regarding the identity of the causative organism in situations in which the corneal scraping is culture negative and may help in choosing the appropriate antimicrobial agent.”
“Association Between Cultures of Contact Lens and Corneal Scraping in Contact Lens-Related Microbial Keratitis”
Sujata Das, MS, FRCS(Glasg); Harsha Sheorey, MD, FRCPA; Hugh R. Taylor, AC, MD, FRANZCO; Rasik B. Vajpayee, MS, FRCS(Edin), FRANZCO
Arch Ophthalmol. 2007;125:1182-1185.
Written by: Christian Nordqvist