RS, a 5-HT4R antagonist; SGS and RO, selective 5-HT6R antagonists; SB, and LY, 5-HT7R antagonists; and the DMSO vehicle control were each administered to 4- to 5-week-old Abca4–/–Rdh8–/– mice by i.p. injection 30 minutes prior to white light exposure at 10,000 lux for 30 minutes. (A) The effect of each treatment was examined by OCT imaging 7 days after light exposure. Representative OCT images featured a disrupted photoreceptor structure only in the DMSO control, as indicated by the asterisk. (B) Statistically analyzed OCT scores (means ± SEM; *P < 0.01 compared with DMSO control). (C) SLO imaging was performed 8 days after light exposure. Representative retinal autofluorescence images show protection by all agents except DMSO. (D) Numbers of retinal autofluorescent spots were counted and statistically analyzed (means ± SEM; *P < 0.01 compared with DMSO control). Scale bars: 50 μm.