ryr3^−/− mice exhibit visual impairment. (A) Cued water maze. Top: Representative heatmaps of the swimming path of WT (left) and ryr3^−/− (right) mice. Bottom left: Total swimming distance (mean ± SEM) required to reach the platform. Bottom right: Time required to reach the platform. Experiments were performed on 10 mice per strain, and data from four different pool entry points were combined. (B) OKR. Top: OptoMotry setup. From Prusky et al. (2004), Fig. 2 B is reprinted with permission from Investigative Ophthalmology & Visual Science. Bottom: Visual acuity of two independent measurements performed under scotopic conditions on each mouse. Each symbol represents the visual acuity of a single mouse; empty circles, WT mice (n = 20); gray circles, ryr3^−/− mice (n = 20). The unit of visual acuity is cycles/degree (c/d). (C and D) Scotopic ERG results of n = 9 WT (empty boxes) and n = 10 ryr3^−/− (gray boxes). Amplitude (in millivolts) of A-waves (C) and B-waves (D); the x axes represent the intensity of the illuminating flash. *, P < 0.05; **, P < 0.005; ****, P < 0.0001, Student’s t test.