Abstract: The present invention relates to an expression cassette allowing expression of a functional LRIT3 protein in mammal eyes; said expression cassette is inserted in an expression vector, preferably an adeno-associated virus (AAV); accordingly, the present invention further relates to a recombinant adeno-associated virus (AAV) vector carrying a nucleic acid sequence encoding a normal LRIT3 gene, or fragment thereof, under the control of regulatory sequences which express the product of the gene in the ocular cells, a pharmaceutically acceptable composition comprising such a recombinant AAV vector and to its use for the treatment of congenital stationary night blindness