The New England College of Optometry, Department of Biosciences and Disease, Boston, Massachusetts.
Optom Vis Sci. 2023 Jan 1;100(1):33-42. doi: 10.1097/OPX.0000000000001967. Epub 2022 Dec 6.
Exposure to blue light before bedtime is purported to be deleterious to various aspects of human health. In chicks, blue evening light stimulated ocular growth, suggesting a role in myopia development. To further investigate this hypothesis, we asked if brief blue light altered the compensatory responses to hyperopic defocus.
Previous work showed that several hours' evening exposure to blue light stimulated ocular growth in chicks, but morning exposure was only effective at a lower illuminance. By contrast, rearing in blue light has inhibited ocular growth in untreated eyes and eyes exposed to form deprivation or defocus. We studied the effects of brief exposures to blue light on the compensation to hyperopic defocus.
Chicks wore monocular negative lenses (-10 D) starting at age 10 days. They were subsequently exposed to blue light (460 nm) for 4 hours in the morning or evening for 8 to 9 days ("dim," 200 lux[morning, n = 9; evening, n = 11]; "bright," 600 lux[morning, n = 8; evening, n = 20]); controls wore lenses in white light (n = 14). Ultrasonography was done on days 1, 5, 8, and 9 for "evening" groups and days 1, 6, and 8 for "morning." All data are reported as interocular differences (experimental minus fellow eyes). Refractions were measured on the last day.
For evening exposure, dim blue light enhanced the axial compensation at all times (change in axial length: day 6: 465 vs. 329 μm/9 days, analysis of variance P < .001, P = .03; day 9: 603 vs. 416 μm/9 days, analysis of variance P < .001; P < .05). Bright blue light had a transient inhibitory effect (day 5: 160 vs. 329 μm; P < .005). Refractive errors were consistent with axial growth, with dim causing more myopia than bright (-9.4 vs. -4.7 D; P < .05). Morning blue light had no significant effect.
We speculate that these findings reflect a complex interaction between illuminance, defocus, and time of day.
睡前暴露在蓝光下据称对人类健康的各个方面都有害。在小鸡中，傍晚的蓝光刺激了眼球生长，表明其在近视发展中起作用。为了进一步研究这一假说，我们询问了短暂的蓝光是否改变了对远视离焦的代偿反应。
先前的工作表明，几个小时的傍晚蓝光暴露会刺激小鸡的眼球生长，但早晨暴露只有在较低照度下才有效。相比之下，在未经处理的眼睛以及接受形觉剥夺或离焦的眼睛中，用蓝光饲养会抑制眼球生长。我们研究了短暂暴露于蓝光对远视离焦补偿的影响。
小鸡从 10 天大时开始佩戴单眼负透镜（-10 D）。随后，他们在 8 到 9 天内的早晨或傍晚接受 4 小时的蓝光（460nm）照射（“暗”，200 lux[早晨，n = 9；傍晚，n = 11]；“亮”，600 lux[早晨，n = 8；傍晚，n = 20]）；对照组佩戴白光下的透镜（n = 14）。对于“傍晚”组，在第 1、5、8 和 9 天进行超声检查，对于“早晨”组，在第 1、6 和 8 天进行超声检查。所有数据均报告为双眼差异（实验眼与对侧眼）。最后一天测量屈光度。
对于傍晚暴露，弱蓝光在所有时间都增强了轴向补偿（眼轴长度变化：第 6 天：465 与 329 μm/9 天，方差分析 P <.001，P =.03；第 9 天：603 与 416 μm/9 天，方差分析 P <.001；P <.05）。强蓝光有短暂的抑制作用（第 5 天：160 与 329 μm；P <.005）。屈光度与轴向生长一致，弱蓝光导致更多的近视（-9.4 与-4.7 D；P <.05）。早晨的蓝光没有显著影响。
我们推测这些发现反映了照度、离焦和时间之间的复杂相互作用。
