RDH5 encodes retinol dehydrogenase 5, a rate-limiting enzyme of the visual cycle that catalyzes NAD-dependent oxidation of cis-isomers of retinol, including 11-cis-, 9-cis-, and 13-cis-retinol, with particular importance in the retinal pigment epithelium 1. The enzyme also recognizes steroid substrates such as androsterone and androstanediol 2. RDH5 localizes to the endoplasmic reticulum, where its stability is regulated by interaction with the heat shock protein HSP90, which prevents autophagic degradation 3. Mutations in RDH5 cause fundus albipunctatus, a congenital stationary night blindness characterized by numerous retinal white-yellow lesions and rod system impairment 45. RDH5-associated retinopathy presents with congenital night blindness and progressive macular atrophy in adult patients, with estimated annual macular volume loss of -0.007 mm³/year 6. Pathogenic variants include missense mutations affecting conserved residues, frameshift deletions, and nonsense mutations that impair protein function and localization 78. Some RDH5 mutations may also cause progressive cone dystrophy beyond rod dysfunction 5. RDH5 mutations account for a minority of macular and cone/cone-rod dystrophy cases among identified genetic causes 9.