Ultra-structural and immunostaining analysis of RDH12-AD retinal organoids revealed shorter photoreceptor segments and reduced cellular numbers than unaffected controls, consistent with shorter cone inner segments and a decreased cone density seen through adaptive optic scanning light ophthalmoscopy (AOSLO) in affected patients (Fingert et al., 2008; Muthiah et al., 2022; Sarkar et al., 2020). The gene discussed is RDH12; the disease is Alzheimer disease.