Damage processes in extended laser exposures using an model.

Retinal pigment epithelial (RPE) cells are sensitive to both photothermal and photochemical damage when exposed to lasers with wavelengths associated with the retinal blue light hazard. Laser power density (irradiance) and exposure duration primarily dictate the damage mechanism. Relatively high irradiances and short exposure durations typically lead to melanin-dependent photothermal damage, whereas low irradiance and long duration exposures are required for photochemical pathways.

Comment on: 'presentation of a novel method to estimate analog mean systemic filling pressure based on cardiac power' -on correlation, coupling, and physiological meaning.

In response to the recent proposal by Monares-Zepeda et al. to estimate mean systemic filling pressure (MSFP) using cardiac power (CP) as a surrogate for the venous return pressure gradient (VRg), we raise concerns regarding the physiological validity and generalizability of the reported correlation. We demonstrate through simulation that the relationship between CP and VRg arises from structural mathematical coupling due to shared dependence on cardiac output (CO), and that this correlation weakens significantly (r = 0.