Figure 4. Outer segment elongation as a function of time. Outer segment elongation was measured in cells dissociated using the enzymatic treatment with gentle pipetting (Protocol A) both in light and dark conditions. Time 0 refers to the time of cell seeding. A: Light-adapted photoreceptors started to lose their native elongated structure (circularity ratio [CR]>0.2) at 40 min and adopted a circular shape (CR approximately 0.8) at 180 min after seeded in culture. Dark-adapted photoreceptors retained their native elongated shape (CR<0.3) throughout the 720 min of study. Error bars represent the standard error of the mean. B: Shown are representative images of light- and dark-adapted photoreceptors.