Exposure to ionizing radiation (IR) could affect the human brain and eyes leading to both cognitive and visual impairments. The aim of this paper was to review and analyze the current literature, and to comment on the ensuing findings in the light of our personal contributions in this field. The review was carried out according to the PRISMA guidelines by searching PubMed, Scopus, Embase, PsycINFO and Google Scholar English papers published from January 2000 to January 2020. The results showed that prenatally or childhood-exposed individuals are a particular target group with a higher risk for possible radiation effects and neurodegenerative diseases. In adulthood and medical/interventional radiologists, the most frequent IR-induced ophthalmic effects include cataracts, glaucoma, optic neuropathy, retinopathy and angiopathy, sometimes associated with specific neurocognitive deficits. According to available information that eye alterations may induce or may be associated with brain dysfunctions and vice versa, we propose to label this relationship “eye-brain axis”, as well as to deepen the diagnosis of eye pathologies as early and easily obtainable markers of possible low dose IR-induced brain damage.

Transcription factors orthodenticle homeobox 2 gene (OTX2), paired box 6 gene (PAX6), and SRY-box transcription factor 2 gene (SOX2) are key regulators of ocular morphogenesis; however, their comparative embryonic localization across species—and the correspondence between transcript and protein distributions—remain incompletely defined. Chromogenic in situ hybridization (CISH) was employed to detect OTX2, PAX6, and SOX2 transcripts, while biotin–streptavidin immunohistochemistry (IHC) was used to assess Otx2, Pax6, and Sox2 protein expression. A semi-quantitative scoring system was applied to evaluate positive structures across ocular compartments. Transcripts were predominantly localized to the retina in both species, with occasional low-level expression in the optic nerve, sclera, and eyelid. Proteins displayed broader distributions: Otx2 was abundant in the retina and eyelid, while Pax6 and Sox2 were detected in multiple tissues, including cornea and extraocular muscles. OTX2, PAX6, and SOX2 show retina-predominant transcription and wider protein expression across ocular tissues. These findings highlight spatial differences between transcript and protein localization, supporting a complex regulatory framework underlying vertebrate eye development.