Graduate School of Integrated Frontier Sciences, Kyushu University, Fukuoka, Japan.
Research Fellow of Japan Society for the Promotion of Science, Fukuoka, Japan.
Ophthalmic Physiol Opt. 2021 Jul;41(4):900-910. doi: 10.1111/opo.12809. Epub 2021 Mar 27.
To investigate the contributions of ocular crystalline lens transmittance spectra and pupil size on age-related differences in the magnitude of light-induced melatonin suppression at night. The first aim was to demonstrate that spectral lens transmittance in children can be measured in vivo with a Purkinje image-based system. The second aim was to test the hypothesis that the magnitude of melatonin suppression in children is enhanced by larger pupils and higher lens transmittance of short wavelengths.
Fourteen healthy children and 14 healthy adults participated in this study. The experiment was conducted for two nights in our laboratory. On the first night, the participants spent time under dim light conditions (<10 lux) until one hour after their habitual bedtime (BT+1.0). On the second night, the participants spent time under dim light conditions until 30 min before their habitual bedtime (BT-0.5). They were then exposed to LED light for 90 min up to BT+1.0. Individual pupil sizes were measured between BT and BT+1.0 for both conditions. Lens transmittance spectra were measured in vivo using the Purkinje image-based system during the daytime. Non-visual photoreception was calculated from lens transmittance and pupil size. This was taken as an index of the influence of age-related ocular changes on the non-visual photopigment melanopsin.
Measured lens transmittance in children was found to be higher than for adults, especially in the short wavelength region (p < 0.001). Pupil size in children was significantly larger than that of adults under both dim (p = 0.003) and light (p < 0.001) conditions. Children's non-visual photoreception was 1.48 times greater than that of adults, which was very similar to the finding that melatonin suppression was 1.52 times greater in children (n = 9) than adults (n = 9).
Our Purkinje image-based system can measure children's lens transmittance spectra in vivo. Lens transmittance and pupil size may contribute to differences in melatonin suppression between primary school children and middle-aged adults.
研究眼球晶状体透过率光谱和瞳孔大小对夜间光诱导褪黑素抑制程度的年龄相关差异的影响。第一个目的是证明可以使用基于普尔金耶像的系统活体测量儿童的光谱晶状体透过率。第二个目的是检验这样一个假设，即儿童的褪黑素抑制程度增强是由于瞳孔较大和较短波长的晶状体透过率较高所致。
本研究纳入了 14 名健康儿童和 14 名健康成年人。该实验在我们的实验室中进行了两个晚上。第一个晚上，参与者在昏暗的光线下（<10 lux）度过时间，直到他们平时的就寝时间后一小时（BT+1.0）。第二个晚上，参与者在昏暗的光线下度过时间，直到他们平时的就寝时间前 30 分钟（BT-0.5）。然后，他们在 BT+1.0 之前暴露于 LED 光下 90 分钟。在这两种情况下，个体瞳孔大小均在 BT 和 BT+1.0 之间进行测量。日间使用基于普尔金耶像的系统活体测量晶状体透过率光谱。从晶状体透过率和瞳孔大小计算非视觉光感受。这被视为年龄相关眼部变化对非视觉光色素褪黑素的影响的指标。
发现儿童的晶状体透过率高于成年人，尤其是在短波长区域（p<0.001）。在昏暗（p=0.003）和亮光（p<0.001）条件下，儿童的瞳孔大小明显大于成年人。儿童的非视觉光感受比成年人高 1.48 倍，这与褪黑素抑制的发现非常相似，即在小学生和中年成年人中，褪黑素抑制程度在儿童中比成年人高 1.52 倍（n=9）。
我们的基于普尔金耶像的系统可以活体测量儿童的晶状体透过率光谱。晶状体透过率和瞳孔大小可能是小学生和中年成年人褪黑素抑制程度差异的原因。
