The prevalence of "infiltrates" in a non contact lens wearing population

Purpose: To determine the prevalence of any corneal "infiltrates" in a non contact lens wearing population. Methods: Twenty-seven non-habitual contact lens wearers (less than 2 hours on average lens wear over the last 2 months) aged between 19 and 46 years were examined each week for a three week period using a Zeiss SL120 biomicroscope. Corneal "infiltrates", defined as an alteration in corneal transparency that seemed to be due to the accumulation of 'cells', were recorded. Further sub-classification was made based on appearance and the presence of symptoms. Results: On the first occasion, the prevalence of symptomatic infiltrates was zero. Five patients had observable "infiltrates" without accompanying symptoms (19%). Over the 81 observations of the twenty-seven patients, twelve different patients were observed to have seventeen episodes of asymptomatic "infiltrates" (21% incidence density). Based on their appearance, and the fact the all the asymptomatic "infiltrates" resolved within one week these seventeen events were considered clinically insignificant. Five patients however were observed to have a second occurrence of "infiltrates" during the four week period The one case of symptomatic "infiltrates" that did not resolve within a week, was considered clinically significant. Conclusions One percent of non contact lens wearers exhibit clinically significant infiltrates, although many more showed some form of very mild disturbance to corneal transparency. Perhaps these small feint "infiltrates" are evidence of "inflammatory cell" presence or activity in the normal cornea. This possible baseline cellular response should be considered when assessing the significance of presumed contact lens related infiltrates.