Jill is a clinical scientist at the Centre for Contact Lens Research, at the School of Optometry and Vision Science, University of Waterloo, Canada.
Download the poster (.pdf), which was shared at the American Academy of Optometry, 2012
Jill Woods, Nancy J Keir, Lyndon W Jones
Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Canada
Purpose: There has been considerable debate regarding the mechanism and clinical relevance of solution-induced corneal staining (SICS). A pilot study was undertaken to investigate various aspects of SICS and the symptoms and typical presentation pattern are reported here.
Methods: Twenty participants wore balafilcon A lenses (PureVisionTM) soaked overnight in a PHMB preserved lens-care solution (Renu FreshTM). Symptom data was collected immediately before and after lens insertion and lens removal. After 2 hours of wear, the lenses were removed and the area of corneal staining was graded.
Results: Sixteen participants (80%) reported symptoms at various stages of the study; only 4 participants (20%) were totally symptom free. Stinging, burning and itching (in this order) were the most commonly reported symptoms during the study period, other than lens awareness. The numbers of participants reporting one or more of these three symptoms across the study were as follows: 2 prior to lens insertion; 6 post lens insertion; 5 after 2 hours lens wear; 13 following lens removal. All twenty participants exhibited SICS (diffuse punctate stain in four or more corneal zones; Carnt et al. CL Spectrum; Sept 2007). Only one participant (5%) exhibited an annular SICS pattern, with lower central staining compared to the peripheral zones; the other 19 (95%) exhibited similar staining across all zones (pan-corneal). The mean staining area across all participants and all zones was 92% (stdev 13%).
Conclusions: Symptoms related to SICS were reported by 80% of participants at some point during the study, and were most prevalent upon lens removal. Overall, stinging was the most commonly reported symptom. Some participants remained symptom-free despite exhibiting high levels of SICS. The pan-corneal staining pattern of SICS was far more prevalent than the annular pattern with this lens and lens-care combination.