School of Optometry, University of California, Berkeley, Berkeley, CA, USA.
Sci Rep. 2019 May 14;9(1):7332. doi: 10.1038/s41598-019-43574-z.
In the context of ocular development and eye growth regulation, retinal defocus and/or image contrast appear key variables although the nature of the signal(s) relayed from the retina to the sclera remains poorly understood. Nonetheless, under optimal visual conditions, eye length is brought into alignment with its optical power to achieve approximate emmetropia, through appropriate adjustment to eye growth. The retinal pigment epithelium (RPE), which lies between the retina and choroid/sclera, appears to play a crucial role in this process. In the investigations reported here, we used a chick model system to assess the threshold duration of exposure to lens-imposed defocus and form-deprivation necessary for conversion of evoked retinal signals into changes in BMP gene expression in the RPE. Our study provides evidence for the following: 1) close-loop, optical defocus-guided (negative and positive lenses) bidirectional BMP gene expression regulation, 2) open-loop, form-deprivation (diffusers)-induced down-regulation of BMP gene expression, and 3) early, transient up-regulation of BMP gene expression in response to both types of lens and diffuser applications. The critical exposure for accurately encoding retinal images as biological signals at the level of the RPE is in the order of minutes to hours, depending on the nature of the visual manipulations.
在眼球发育和眼生长调控的背景下，视网膜离焦和/或图像对比度似乎是关键变量，尽管视网膜向巩膜传递的信号的性质仍不清楚。尽管如此，在最佳视觉条件下，眼睛的长度通过适当的眼生长调整与光学功率相匹配，从而实现近似正视。位于视网膜和脉络膜/巩膜之间的视网膜色素上皮（RPE）似乎在这个过程中起着至关重要的作用。在本研究中，我们使用鸡模型系统来评估将晶状体引起的离焦和形态剥夺转化为 RPE 中 BMP 基因表达变化所需的暴露时间阈值，以评估对眼睛的影响。我们的研究提供了以下证据：1）闭环、光离焦引导（正、负透镜）双向 BMP 基因表达调控；2）开环、形态剥夺（扩散器）诱导的 BMP 基因表达下调；3）对两种类型的透镜和扩散器应用的早期、短暂的 BMP 基因表达上调。将视网膜图像作为 RPE 水平的生物信号进行精确编码的关键暴露时间在几分钟到几小时之间，具体取决于视觉处理的性质。
