In-vitro retinal model reveals a sharp transition between laser damage mechanisms

We use laser damage thresholds in an in-vitro retinal model, and computational simulations to examine the laser exposure durations at which damage transitions from photothermal to photochemical at 413 nm. Our results indicate a dramatic shift in 1-h damage thresholds between exposure durations of 60 and 100 s. The trend in our in-vitro results is similar to a trend found in a recent study where retinal lesions were assessed 1-h post laser exposure in the rhesus eye Our data suggest that nonthermal mechanisms did not significantly contribute to cell death, even for exposures of 60 s. Knowledge of the transition point, and lack of concurrent thermal and nonthermal damage processes, are significant for those wishing to devise a comprehensive computational damage model.