Methods and compositions for recovering or improving visual function

A method for increasing an amount of melanosomes in a mammalian subject suffering from ocular albinism type I as compared to a non-treated subject, said method comprising:

• a) providing a recombinant adeno-associated viral (AAV) vector carrying an expression cassette which contains a nucleic acid molecule encoding an orphan G-protein coupled receptor (OA1) that crosses melanosomal membranes, wherein said nucleic acid molecule is selected from the group consisting of SEQ ID Nos. 1 and 2, and wherein said nucleic acid molecule is operably linked to a promoter selected from the group consisting of SEQ ID Nos. 3, 4, and 5;
• and
• b) transducing retinal pigment epithelial cells with said recombinant AAV vector by administering said vector by subretinal injection, whereby said nucleic acid molecule is expressed by the retinal pigment epithelial cells in said mammalian subject.