Figure 1. Fundus photos and SD-OCT images of the IRBP KO and WT mouse eye. Spectral domain optical coherence tomography (SD-OCT) and fundus images were obtained non-invasively in living mice at different ages (P15, P30, P45, and P80) in this representative figure. A–H illustrate clear optical media in the wild-type (WT) and interphotoreceptor retinoid-binding protein (IRBP) knockout (KO) mouse eye. No cloudiness or haze was detected in the cornea, anterior chamber, lens, or vitreous at P30 (C–D), P45 (E–F), and P80 (G–H) in the IRBP KO or WT mouse. Slight haze or cloudiness was observed at slightly greater levels in the P15 KO mouse fundus (B) than in the WT mouse fundus (A), but the SD-OCT images were equally crisp. This cloudiness appeared to be caused by the presence of residual hyaloid vasculature near the optic nerve detected in histological sections. In the IRBP KO mouse, outer nuclear layer (ONL) thickness is lost between P15 and P30 in the living KO mouse eye. The fundus photos showed mottling at P30, P45, and P80 that was not detected at P15 in the same IRBP knockout mouse (indicated by arrows). No mottling was observed in the WT mice at any age. At P80, distinct focal white spots were observed in the IRBP KO mice (marked by a white boundary). There was a loss in thickness in the ONL of the P15–P80 KO mouse compared to the P15–P80 WT mouse. These live images validate previous work on histological sections from enucleated eyes [22]. The SD-OCT images established that the retinal and ONL thickness develops fully, and then cells are lost through a degenerative process by P30.