Contact Lenses as a Diagnostic Tool I: The Uptake and Release of Steroid Hormones by Commercial Hydrogel Lenses

Abstract

Abstract: : Purpose:The presence of female hormones in the tear film has been documented and correlated to serum levels (Carney et al. 2005, The Ocular Surface, 3, s52). The purpose of this study was to determine if contact lenses can be used as a collection device for such analytes in tears allowing the monitoring of fertility through tear fluid. Methods:Nelfilcon A lenses (–0.50 diopters) were incubated with either ³H–estradiol (2–3000pg/ml) or ³H–progesterone (5–100nM) diluted in phosphate buffered saline (PBS) or artificial tear solution (ATF) for 2 hrs at room temperature with shaking. The lenses were stored over night at 4^oC, then the amount of hormone bound was determined by liquid scintillation counting. This data was then confirmed by soaking lenses in non–radiolabelled estradiol (0–500pg/mL) and progesterone (1–100nM) and detected via competitive immunoassay. Release of progesterone from lenses after absorption was investigated by soaking in 200µl of 5% ethanol solution for 2 minutes, 10 minutes and 3 hours. Results:Both hormones were significantly bound to the contact lenses in a concentration dependent manner (up to 350pg/lens estradiol and 870pg/lens progesterone, n=2). Maximum uptake was achieved by 2 hours of incubation with no further increase being noted with longer incubation times. For estradiol, binding was greatest when PBS (0.4 to 350pg/lens) was used rather than ATF (0.4 to 159pg/lens). These results were confirmed by the competitive immunoassay technique. 95% of progesterone absorbed by the nelfilcon A lens was recovered within 2 minutes of soaking in 200ul of 5% ethanol solution. Conclusions:The results of this preliminary study indicate that contact lenses can successfully be used as a collection device for diagnostics through tear fluid. Progesterone and estradiol are taken up by contact lenses in a concentration dependent manner and can be released within 2 minutes.

Keywords: contact lens • cornea: epithelium • cornea: basic science