PURPOSE. Silicone-hydrogel contact lenses offer a high level of oxygen transmissibility that should alleviate longer term hypoxic problems in continuous wear. In this report, we analyse ocular physiological changes and symptoms in a group of patients who have successfully worn silicone-hydrogel contact lenses in continuous wear mode over a 3 year period. METHOD. Successful daily wear patients were introduced to continuous wear with silicone-hydrogel (balafilcon A) lenses at a site in Melbourne, Australia and another in Luzern, Switzerland. Lenses were worn on a 30-day (29-night) continuous basis. Ongoing subjects participated in clinical trials during the first 2 years, and continued as clinical practice patients during the 3rd year. Data from lens delivery (baseline) and after one week of continuous wear were used as the basis for comparison for symptoms and slit-lamp evaluation of the eyes in subjects completing 3 years of continuous wear. Data from 23 subjects was available for evaluation.
RESULTS. Results of ocular signs remained favourable over the three year period, with corneal epithelial edema, microcysts, corneal staining, striae, neovascularization and bulbar conjunctival injection being statistically indistinguishable from both the baseline and one week visits. A significant reduction in limbal injection was observed after three years compared to both baseline and the one week visit. There was no change in symptoms of burning, blur, variable vision, handling excess tearing, secretion or photophobia over the three year period. Discomfort and dryness were both significantly reduced compared to the one week visit.
CONCLUSIONS. Patients who have been successful with silicone-hydrogels in continuous wear for up to 3 years do not appear to show unfavourable responses in terms of ocular health and symptoms. These results should be kept in context in that the selection of patients for this analysis may exclude discontinuing patients who have shown adverse hypoxic responses.