Contact Lens Solutions Toxicity Evaluation by the Bioluminescence Method

Abstract

Purpose. To study the possibility of using bioluminescence biotesting to evaluate the toxicity of contact lens care solutions.Methods. The examined solutions were tested both immediately upon unpacking (i.e. sterile) and after rinsing “Pure Vision 2” lenses in them (i.e. after use). As a test system, NADH:FMN oxidoreductase and luciferase bacterial bio enzyme system was used. It contained lyophilized highly purified ferments of EC 1.14.14.3 bacterial luciferase (0.4 mg/ml) from E.coli recombinant variant and EC 1.5.1.29 NADH:FMN oxidoreductase (Ph. leiognathi) (0.18 enzyme units). The bioluminescent testing was carried out with TriStar LB 941 microplate luminometer (Germany). The measurement of the luminescence intensity was carried out in two repetitions. Residual luminescence (T, %), calculated as the ratio of the average maximum luminescence intensities of the experimental measurement (solution) and the control measurement, multiplied by 100%, was used as an integral indicator. Results. The results of bioluminescent testing of sterile solutions showed that “Maxima” solution exhibited the greatest inhibition of bioluminescence, while “Optimed” (Russia) and “AVIZOR Aqua Soft Comfort” solutions demonstrated the least effect. “Bausch + Lomb Biotrue” solution did not affect the bioluminescence. The results of bioluminescence testing of the solutions after contact lenses that had previously been worn for 10 hours were stored in them, showed a strong inhibition of bioluminescence in all solutions. Conclusion. The results of the toxicity evaluation allow for a more reliable prognosis of the long-term consequences of using certain solutions by contact lens wearers from risk groups. The findings also provide more insight into the mechanisms of development of discomfort and other reasons for refusing to wear lenses, as well as to suggest more effective prevention measures.