Dry eye following cataract surgery: The effect of light exposure using an in-vitro model

Purpose: Cataract surgery can lead to the temporary development or worsening of dry eye symptoms.Contributing factors may include corneal incisions, agents used before, during or after surgery, light from the operating microscope, disruption of ocular surface tissues and inflammatory processes. The purpose of this study was to observe the effect of light exposure on conjunctival fibroblasts in order to determine whether light has an effect on wound healing closure, assuming that operating microscopes might have an effect on the ocular surface. Method: An in vitro scratch assay was performed on porcine conjunctival fibroblasts. Ten minutes of light exposure from a light microscope with halogen bulb was performed after the scratch assay. Fibroblasts were kept in culture for 48 hours post-exposure and the wound closure rates were visualized by live/dead staining. The fibroblasts which were exposed to light were compared to those without light exposure. Cell viability was also analysed by MTT assay. Results: Slower wound closure rate was found when fibroblasts were exposed to light compared to the non-light exposed controls. Cell viability reduced by 20% with light exposure compared to controls in p3 cells (p = 0.04; however, the trend was not observed with p4 and p5 cells (p > 0.05). Conclusions: These results suggest that light exposure might be one of the possible contributory factors for dry eye after ophthalmic surgery. Further evaluation of light effects should be carried out with different ocular surface cells