Figure 1.

An example of the change in PO₂ in the distal retina during 2 min of illumination at 8.5 log quanta (555 nm)-deg^−2-sec⁻¹. The solid line superimposed on the data shows a single exponential equation fitted to the data. Light was on between t =30 and t =150 sec. In this example, the PO₂ returned to baseline 90 sec after the light was turned off. Baseline PO₂, the maximum PO₂ during illumination, and the difference between them are defined as P_min, P_max, and ΔPO₂ respectively.