Catalyzes the saturation of all-trans-retinol to all-trans-13,14-dihydroretinol. In addition, saturates the 7-8 double bond of all-trans-retinol to produce all-trans-7,8-dihydroretinol. Can also use vitamin A2 (all-trans-3,4-didehydroretinol) as a substrate, to produce all-trans-13,14-dihydro-3,4-didehydroretinol or all-trans-7,8-dihydro-3,4-didehydroretinol. May play a role in vitamin A metabolism. A + all-trans-13,14-dihydroretinol = AH2 + all-trans-retinol Expressed in liver at 72 hours post-fertilization (hpf) and gut at 96 hpf. Not detected at earlier stages of development. Belongs to the carotenoid/retinoid oxidoreductase family. CrtISO subfamily.