Abstract
Purpose :
The retinal mechanisms underlying the relationship between chromatic cues and refractive development remain unclear. While the literature supports the involvement of cones in the refractive shifts seen in investigations of longitudinal chromatic aberrations (LCA), the mouse model has not been used to investigate the effects of monochromatic light exposure on refractive development.
Methods :
C57BL/6J mice received a head-mounted goggle holding a -10 diopter (D) lens over the right eye at post-natal day 28 (P28). Age-matched control mice did not wear a lens. Mice were housed in one of three LED lighting conditions: 400 nm (violet), 525 nm (green), or standard white light (~420-680 nm) (n=3-6/condition). Refractive error, corneal curvature, and ocular axial parameters were measured weekly until P56 using photorefraction, keratometry, and spectral-domain optical coherence tomography (SD-OCT), respectively. Two-way repeated measure ANOVAs with Holm-Sidak post-hoc comparisons were used to determine significant differences between groups across time.
Results :
At P56, control mice exposed to 400 nm light were significantly more hyperopic than mice exposed to 525 nm and white light (mean refractive error ± SEM, 400 nm: 7.54 ± 0.46 D; 525 nm: 5.25 ± 0.15 D; white: 4.82 ± 0.12 D, p<0.05). Likewise, mice exposed to 400 nm light with lens defocus demonstrated a significantly reduced myopic shift (lens defocus eye – naïve contralateral eye) when compared to lens defocus mice exposed to 525 nm and white light at P56 (mean shift in refractive error ± SEM, 400 nm: -2.62 ± 0.75 D; 525 nm: -4.02 ± 0.75 D; white: -5.63 ± 0.59 D, p<0.05). The data did not demonstrate significant shifts in corneal curvature or ocular axial parameters between groups.
Conclusions :
The reduced myopic shifts in response to -10 D lens defocus in the mouse eye may be due to 400 nm light converging more anteriorly in the eye compared to 525 nm or white light based on the theory of LCA. Notably, the 525 nm and white light had similar peak intensity wavelengths, and the mice in these groups did not have significantly different refractive errors by P56. Future experiments will utilize mouse models with cone mutations to further investigate retinal mechanisms.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.