Phototoxicity of Ultraviolet (UV) Radiation: Evaluation of UV-Blocking Efficiency of Intraocular Lens (IOL) Materials Using Retinal Cell Culture and in vitro Bioassays

This work involves the evaluation of UV blocking efficiency of commercially available intraocular lens (IOL) materials using a retinal cell culture and a biological in vitro model that was developed in a previous study, as an effort to examine the sensitivity of this in vitro approach for evaluating toxicity of UV radiation on the retinal pigment epithelial cells. The human retinal pigment epithelial (RPE) cell line, ARPE-19, was cultured, and cells were irradiated with broadband UVB radiations at energy levels of 0.2 and 0.4 J/cm . Some treated cells were not shielded from the radiation while others were shielded using two thicknesses (0.9 and 1.5 mm) of IOL material. After irradiation, cellular viability, mitochondrial distribution, nuclei morphology, and phagocytotic activity were analyzed using the Alamar blue assay, Rhodamine 123 staining, the Hoechst assay, and a phagocytotic activity assay. The results demonstrate that UVB radiation can cause significant decreases in RPE cell viability as well as in phagocytotic activity. Also, the results show that UVB radiation can induce the degradation of DNA and mitochondria in cultured RPE cells. However, the two different thickness IOL material sheets (0.9 and 1.5 mm) showed very effective UV blocking ability, allowing no cellular damage at all. Thus, the finding suggest that these four assays together can be used as a sensitive, and meaningful in vitro biomarker method for evaluating toxicity of UV radiation on RPE cells, and also for examining IOL effectiveness.