NR2E3 and night blindness: Besides the ERG, there are more clinical similarities between ESCS caused by NRL and NR2E3 mutations, like age of onset in childhood, nyctalopia, normal-to-reduced visual acuity, hyperopia, and constricted visual fields, a variable degree of divergent or convergent strabismus, and a slowly progressive nature of the disease [4,5,26,28].