Quantitative analyses of photoreceptors death. (A) TUNEL + photoreceptor cells were counted across the retina (from the inferior to superior) in 0d, 3d, 7d, 10d and 14d animals and data from Nontreated (solid colored lines) and 670 nm Treated (broken colored lines) groups were compared. TUNEL + cells were present in the inferior central area (hotspot) of the nontreated retinas from 3d (solid red line) and the number of cell death increased as a function of hyperoxia-exposure time. (B) In the 14dNT retinas (solid green line), hyperoxia exposure caused widespread cell death that also affected the photoreceptors in the superior retina. By contrast, these numbers were significantly reduced by 670 nm light pretreatment. *Statistically significant difference (p < 0.001) compared to NT groups.