“…The absence of blood relationship and above all the sporadic occurrence of the unilateral form were explained by the hypothesis that it represents an exceptional recessive gene at the heterozygote state whose appearance would be favored by genetic factors, like altered genes, of a changed unilateral circulatory situation in the area of the ophthalmic artery [9, 10]. Although a large number of bilateral cases have been reported, truly unilateral cases are very rare because the disease often has a different progression in the two eyes [3, 11, 12]. Taking into consideration the rarity of this disease (about 50 cases reported in the literature up to now), this work gives us the possibility to evidence the importance of electrofunctional examination, actually performed and evaluated according to the ISCEV standard [4, 5], in the correct framing of the atypical forms of RP.…”