title: Photopic visual input is necessary for emmetropization in mice.
abstract: It was recently demonstrated that refractive errors in mice stabilize around emmetropic values during early postnatal development, and that they develop experimental myopia in response to both visual form deprivation and imposed optical defocus similar to other vertebrate species. Animal studies also suggest that photopic vision plays critical role in emmetropization in diurnal species; however, it is unknown whether refractive eye development is guided by photopic vision in the mouse, which is a nocturnal species. We used an infrared mouse photorefractor and a high-resolution MRI to clarify the role of photopic visual input in refractive eye development in the mouse. Refractive eye development and form-deprivation myopia in P21-P89 C57BL/6J mice were analyzed under 12:12 h light-dark cycle, constant light and constant darkness regimens. Animals in all experimental groups were myopic at P21 (-13.2 ± 1.6 D, light-dark cycle; -12.5 ± 0.9 D, constant light; -12.5 ± 2.0 D, constant dark). The mean refractive error in the light-dark-cycle-reared animals was -0.5 ± 1.3 D at P32 and, and did not change significantly until P40 (+0.3 ± 0.6 D, P40). Animals in this group became progressively hyperopic between P40 and P89 (+2.2 ± 0.6 D, P67; +3.7 ± 2.0 D, P89). The mean refractive error in the constant-light-reared mice was -1.0 ± 0.7 D at P32 and remained stable until P89 (+0.1 ± 0.6 D, P40; +0.3 ± 0.6 D, P67; 0.0 ± 0.4 D, P89). Dark-reared animals exhibited highly hyperopic refractive errors at P32 (+5.2 ± 1.8 D) and became progressively more hyperopic with age (+8.7 ± 1.9 D, P40; +11.2 ± 1.4 D, P67). MRI analysis revealed that emmetropization in the P40-P89 constant-light-reared animals was associated with larger eyes, a longer axial length and a larger vitreous chamber compared to the light-dark-cycle-reared mice. Constant-light-reared mice also developed 4 times higher degrees of form-deprivation myopia on average compared to light-dark-cycle-reared animals (-12.0 ± 1.4 D, constant light; -2.7 ± 0.7 D, light-dark cycle). Dark-rearing completely prevented the development of form-deprivation myopia (-0.3 ± 0.5 D). Thus, photopic vision plays important role in normal refractive eye development and ocular response to visual form deprivation in the mouse.
authors.affiliation: Department of Anatomy and Cell Biology, Wayne State University, Detroit, MI 48201, United States.
authors.forename: Tatiana V
authors.initials: TV
authors.lastname: Tkatchenko
authors.forename: Yimin
authors.initials: Y
authors.lastname: Shen
authors.forename: Rod D
authors.initials: RD
authors.lastname: Braun
authors.forename: Gurinder
authors.initials: G
authors.lastname: Bawa
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.forename: Ivan
authors.initials: I
authors.lastname: Avrutsky
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Tkatchenko
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D055253:Color Vision / Q000502:physiology*; D003623:Dark Adaptation; D004195:Disease Models, Animal; D058453:Emmetropia / Q000502:physiology*; D006956:Hyperopia / Q000503:physiopathology*; D008027:Light; D008279:Magnetic Resonance Imaging; D051379:Mice; D008810:Mice, Inbred C57BL; D009216:Myopia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology; D012683:Sensory Deprivation
keywords: emmetropization; form deprivation; mouse model; myopia; photopic vision