Abstract
Purpose :
In several species, the effects of narrowband lighting on refractive development depend on the peak wavelength. In monkeys, quasi-monochromatic, long-wavelength lighting consistently produced progressive hyperopic shifts, augmented the hyperopia produced by myopic defocus, but prevented the axial myopia produced by hyperopic defocus. The purpose of this study was to determine the effects of narrowband, short-wavelength lighting on refractive development in infant rhesus monkeys.
Methods :
Starting at 23±3 days of age, infant monkeys (Macaca mulatta) were reared under short-wavelength LED lighting (465 nm; illuminance = 183±28 lux) with unrestricted vision (BL controls, n=5) or with a +3 D (+3D-BL, n=7) or -3 D (-3D-BL, n=6) lens in front of one eye and a plano lens in front of the fellow eye. Refractive development, corneal power, and vitreous chamber depth were measured every two weeks by retinoscopy, keratometry, and ultrasonography, respectively. Comparison data were available from previous studies for similar subject groups housed under white fluorescent lighting (e.g., WL controls) or quasi-monochromatic, equal-energy red light (630 nm; e.g. +3D-RL).
Results :
Refractive development was generally more variable in BL than in WL and after four months of treatment there was a non-significant trend for the BL controls (+3.19 D) to exhibit more hyperopia than WL controls (+2.50 D, P=0.08), but less hyperopia than RL controls (+3.56 D, P=0.10). All monkeys in the +3D-BL group exhibited compensating hyperopic anisometropias (median OD: +5.63 D, OS: +3.50 D); the degree of anisometropia and the absolute refractive errors for both their treated and fellow eyes were comparable to those of +3D-WL and +3D-RL animals (P=0.053 to 0.85). In contrast to -3D-RL monkeys, the majority of -3D-BL animals exhibited some compensating anisometropia and both the treated (+5.97 D vs +1.85 D, P=0.02) and fellow eyes were less hyperopic (+6.25 D vs + 2.99D, P=0.02). All the between eye and between group refractive-error differences were correlated with differences in vitreous chamber depth.
Conclusions :
Like quasi-monochromatic, red lighting, narrowband blue light interfered with refractive development, however the patterns of alterations were different for the two wavelength bands. Overall the results support the hypothesis that chromatic cues facilitate emmetropization.
This is a 2020 ARVO Annual Meeting abstract.