Abstract
Purpose: :
To evaluate cellular viability of mammalian cells exposed to soft contact lens care products (SCLC) using in vitro cell culture methods.
Methods: :
The lens care products used were: Clear CareTM; AQuifyTM MPS( SOLOcare®AQUA) (CIBA Vision) and ReNu MPS® with Moisture LocTM (Bausch and Lomb). Cellular viability assays used were, Alamar BlueTM (AB), Neutral Red Release Assay (NRR), Neutral Red Uptake and Release Assay (NRUR), the USP modified Elution Assay (ELT) and Flow Cytometry Live Dead Cell Viability Assay (LDCV). Following an incubation period, L929 murine fibroblastic cells (L929) and SV 40 human corneal epithelial cells (HCE–T) were exposed to SCLC and cellular viability was evaluated by either vital or cytometric dyes. Benzalkonium chloride (BAC) was used as a positive control for the analysis of dead cells.
Results: :
Cell viability was significantly different between the 3 SCLC solutions and the type of in vitro assay used. Clear CareTM and SOLOcareTM Aqua were non–cytotoxic in the AB, NRR, NRUR, ETL and the LDCV assay at all concentrations and time points tested for both L929 and HCE–T cells. ReNU MPS® with Moisture LocTM was found cytotoxic at 50% in the AB test for both cell types; cytotoxic in the NRUR test at 50% and 25% in both cell types; cytotoxic in the ELT assay in both cell types, non–cytotoxic at 1 and 15 minutes in the NRR assay and had reduced cell viability in the LDCV assay. BAC exposed cells were cytotoxic in the AB, NRR, NRUR, ETL and LDCV assays at concentrations used respective to exposure time points.
Conclusions: :
AB, NRR, NRUR and LDCV flow cytometry studies demonstrate the biocompatibility of Clear CareTM and SOLOcareTM Aqua with both L929 and HCE–T cells. These tests with other toxicological tests provide valuable information for the evaluation of new solutions. All of these assays help differentiate subtle differences in LCPs.
Keywords: contact lens • cornea: basic science • cell survival