Mutations which affect RPE function do not usually lead to alterations in eye size, rather the usual outcome is degeneration of the photoreceptors, for example loss-of-function of RPE65 can lead to retinitis pigmentosa or leber congenital amaurosis [48, 49] and mutations in C1QTNF5 can result in late-onset retinal macular degeneration [50]. Here, RPE65 is linked to Leber congenital amaurosis.