9-cis-β-Carotene, a precursor of retinal, is cleaved by beta-carotene oxygenase 1 (BCMO1) to produce 9-cis-retinal, which inhibits photoreceptor degeneration and restores retinal function in vivo.

9-cis-β-Carotene (1 μM; 18 hours), combined with Miglyol 810 and an antioxidant mix, is applied to eye cups derived from RPE65rd12 mice with the neuro-retina still attached to the underlying RPE tissue. This treatment significantly prevents degeneration of S- and M-cones, resulting in more than a 2- and 9-fold increase in m-opsin and s-opsin positive staining, respectively, compared to the control group.

In a mouse model exhibiting defects in the retinoid cycle, specifically the RPE65rd12 mutation, administration of an extract from Dunaliella Bardawil algae, which is rich in 9-cis-β-Carotene (9CBC), via oral route, has been shown to rescue retinal function and preserve cone structure.