Abstract
Purpose :
To investigate whether infant monkeys compensate for imposed hyperopic defocus when they are reared under quasi-monochromatic long-wavelength lighting.
Methods :
Starting at 23±3 days of age, 6 infant monkeys were reared under long-wavelength LED lighting (630 nm, 260 lux) with -3.0D spectacle lenses over their treated eyes and zero-powered lenses over their fellow eyes (-3DRL). Comparison data were previously obtained from infants reared under the same long-wavelength lighting with unrestricted vision (NRL; n=7) and with monocular +3.0D lenses (+3DRL; n=7). Additional control data obtained under typical white fluorescent lighting (480 lux) were available for infants reared with unrestricted vision (NWL; n=35), monocular -3.0 (-3DWL; n=14), and monocular +3.0 D lenses (+3DWL; n=7). Each eye’s refractive status, corneal power, and axial dimensions were measured every 2 weeks until the end of the lens-rearing period.
Results :
At 130 days of age, in comparison to NWL monkeys, the median ametropias were significantly more hyperopic for both eyes of the NRL (right eyes: +3.57D vs +2.44D, p=0.003), and the -3DRL monkeys (treated eyes: +5.88D, p=0.007; control eyes: +5.94D, p=0.003). In contrast to animals reared in white light, the -3DRL monkeys exhibited no significant inter-ocular differences in refractive error (+0.13±0.86, p=0.74). On the other hand, the +3DRL monkeys exhibited significant compensating hyperopic anisometropias (+1.29 ± 0.51D, p=0.001) that were comparable to those observed in +3DWL subjects (+1.71±0.39D, p=0.0001). However, like the -3DRL monkeys, the ametropias in both the treated and fellow eyes of the +3DRL monkeys were significantly more hyperopic than those of NWL monkeys (treated eyes: +6.06D, p=0.0001; control eyes: +4.69D, p=0.0008). All of the relative hyperopic ametropias were associated with the shorter vitreous chamber depths.
Conclusions :
Long-wavelength lighting slows axial elongation, produces hyperopic refractive error shifts, prevents anisometropic compensation for imposed hyperopic defocus, but allows anisometropic compensation for imposed myopic defocus. These findings are in agreement with the hypothesis that chromatic cues provide directional cues for emmetropization and that long-wavelength lighting compromises the ability of the eye to respond to hyperopic defocus.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.