BCL2 and psychosocial stress measurement: Using the Bcl-2/Bax ratio as an established measure to determine cellular sensitivity to apoptotic stimuli in RPE cell models27, we also observed that the Bcl-2/Bax ratio decreased in a time-dependent manner upon BFA-induced ER stress in ARPE-19, supporting the finding that the induced ER stress is associated with increased pro-apoptotic signalling (Fig. 2c,d).