Retina conditions and disorders,such as age-related macular degeneration (AMD),diabetic retinopathy (DR),retinitis pigmentosa (RP) and retinal or choroidal tumors,are relevant diseases to retinal neurons and vasculatures.Although genetic factors such as gene mutation and single nucleotide polymorphisms cause changes of gene expression and involve in the pathogenesis of certain retinal diseases,the alteration of gene expression can be observed without changing the genome sequences under the external or internal stimuli.This epigenetic role,especially histones and its modification,has been considered as a part of mechanisms of those diseases described above.Current advances have drawn our attentions to this field in both pathological and therapeutical challenges of retinal diseases.