Abstract
Purpose :
Circadian rhythms in ocular tissues play important roles in homeostasis, photoreceptor disc shedding, and visual function and are also thought to influence ocular growth and emmetropization. To test whether circadian disruption caused by environmental light affects refractive development, we utilized an experimental model of environmental circadian disruption and longitudinally measured refractive error in mice.
Methods :
Wild-type C57Bl/6J male and female mice were developmentally exposed throughout gestation and after weaning to either a control light (CL, 12:12 light:dark, n=17-20) or environmental circadian disruption (CD, weekly light:dark inversions, n=16-22) light cycle. Refractive error (photorefractometry), corneal curvature (keratometry), and eye biometry (spectral domain optical coherence tomography) were measured at 4, 5, and 6 weeks of age. A mixed-effects analysis with Sidak’s method to control for multiple comparisons (significance threshold p<0.05) was performed to test for differences in refractive error and corneal curvature by treatment group and time. Student’s unpaired t-tests (significance threshold p<0.05) were used to evaluate differences in eye biometry measures in a subset of mice (n=14 CL, n=12 CD) at 4 weeks of age.
Results :
Mice in the CD group had greater refraction values compared to CL at 4, 5, and 6 weeks of age (Figure 1, main effect of group, F (1, 41) = 174.7, p<0.001). Corneal curvature does not appear to significantly differ between groups, but eye biometry measures from a subset of mice suggest trends towards decreased corneal thickness (p=0.122), decreased lens thickness (p=0.117), and shorter axial length (p=0.283), in the CD mice.
Conclusions :
These results suggest that the developmental light environment can influence refractive error. We plan to further evaluate eye biometry measures in the remaining mice at all time points. Because mice were kept in the light conditions for the duration of the experiment, it is possible that circadian changes in choroidal dynamics may also play a role in these results.
This is a 2021 ARVO Annual Meeting abstract.