Liu Hong, Schaeffel Frank, Feldkaemper Marita Pauline
Section of Neurobiology of the Eye, Ophthalmic Research Institute, University of Tübingen, Tübingen, Germany.
Aier Institute of Optometry and Vision Science, Aier Eye Hospital Group, Changsha, China.
Front Med (Lausanne). 2024 Dec 10;11:1469275. doi: 10.3389/fmed.2024.1469275. eCollection 2024.
Changes in choroidal thickness (ChT) are proposed to predict myopia development but evidence is mixed. We investigated time courses of choroidal responses, following different types of dynamic artificial stimulation in chicks with and without spectacle lenses, as well as changes in retinal dopamine metabolism and expression of candidate genes.
Chicks were kept in an arena surrounded by computer monitors presenting dynamic checkerboard fields of small, medium and large size. Fields were displayed with different cycle frequencies, as ON (rapid rise, slow decay) or OFF (slow rise, rapid decay) temporal luminance profile. Refractive errors, ocular biometry and ChT were assessed. Dopamine metabolism and candidate gene expression levels were also measured. Stimuli were applied for (1) 3 h with no lens, (2) 3 h and monocular treatment with -7D or +7D lenses, (3) 3 or 7 days.
(1) The smallest fields caused the largest decrease in ChT. (2) Negative lens treatment induced on average 11.7 μm thinner choroids. ChT thinning was enhanced by 10 Hz-ON medium field size flicker which also reduced choroidal thickening with positive lenses. (3) With prolonged treatment, the choroid recovered from initial thinning in all groups although to varying degrees which were dependent on stimulus parameters. Relative ChT changes were positively correlated with the vitreal level of dopamine metabolites. Retinal mRNA level was positively correlated with choroidal thickness. Retinal melanopsin mRNA was increased by 10 Hz-ON stimulation and choroidal mRNA increased with 10 Hz-OFF stimulation. On average, early choroidal thinning did not predict the amount of negative lens-induced eye growth changes after 7 days, whereas later ChT changes showed a weak association.
Negative lenses caused long-lasting choroidal thinning, with some recovery during lens wear, especially after stimulation with 10 Hz. The dynamic stimuli modulated choroidal thinning but effects were small. There was little difference between ON and OFF stimulation, perhaps because the checkerboard patterns were too coarse. 10 Hz cycle frequency increased dopamine release. Less dopamine was correlated with thinner choroids. Result do not exclude a predictive value of choroidal thickening for future refractive development since we almost exclusively tested choroidal thinning effects.
脉络膜厚度（ChT）的变化被认为可预测近视发展，但证据不一。我们研究了在有或无眼镜镜片的雏鸡中，不同类型动态人工刺激后脉络膜反应的时间进程，以及视网膜多巴胺代谢和候选基因表达的变化。
将雏鸡饲养在由计算机显示器环绕的场地中，显示器呈现小、中、大尺寸的动态棋盘格图像。图像以不同的循环频率显示，具有开（快速上升、缓慢衰减）或关（缓慢上升、快速衰减）的时间亮度曲线。评估屈光不正、眼生物测量和脉络膜厚度。还测量了多巴胺代谢和候选基因表达水平。刺激分别施加（1）3小时无镜片，（2）3小时单眼佩戴-7D或+7D镜片，（3）3天或7天。
（1）最小尺寸的图像导致脉络膜厚度下降最大。（2）负镜片处理平均使脉络膜变薄11.7μm。10Hz开式中尺寸图像闪烁增强了脉络膜变薄，同时也减少了正镜片引起的脉络膜增厚。（3）随着处理时间延长，所有组的脉络膜从最初的变薄中恢复，尽管恢复程度不同，这取决于刺激参数。脉络膜厚度的相对变化与玻璃体中多巴胺代谢物水平呈正相关。视网膜mRNA水平与脉络膜厚度呈正相关。视网膜黑视蛋白mRNA在10Hz开式刺激下增加，脉络膜mRNA在10Hz关式刺激下增加。平均而言，早期脉络膜变薄并不能预测7天后负镜片诱导的眼生长变化量，而后期脉络膜厚度变化显示出较弱的相关性。
负镜片导致脉络膜长期变薄，在佩戴镜片期间有一定恢复，尤其是在10Hz刺激后。动态刺激调节了脉络膜变薄，但效果较小。开式和关式刺激之间差异不大，可能是因为棋盘格图案太粗糙。10Hz循环频率增加了多巴胺释放。多巴胺越少与脉络膜越薄相关。由于我们几乎只测试了脉络膜变薄的影响，结果不排除脉络膜增厚对未来屈光发展的预测价值。
