Pearson A A
J Anat. 1980 Jan;130(Pt 1):33-42.
The sequence of developmental events leading to the formation of the eyelids is described in staged human embryos. By the end of the fourth week the optic vesicle lies close to the surface ectoderm. The surface ectoderm overlying the optic vesicle, in response to this contact, has thickened to form the lense placode (Stage 13). A few days later (about 32 days, Stage 14) the lens placode is indented by the lens pit. A day or two later (about 33 days, Stage 15) the lens pit is closed: however, the lens vesicle and optic cup lie close to the surface ectoderm and appear to press against the surface. Prior to the development of the eyelids, one small sulcus or groove forms above the eye (eyelid groove) and another below it (stage 16, 37 days). As these grooves deepen, in Stages 17--19, eyelid folds develop, first below, and then above, the eye. In Stages 19--22 the eyelid folds develop into the eyelids and cover more of the eye as the palpebral fissure takes shape. The upper and the lower eyelids meet at the outer canthus in Stage 19. The inner canthus is established a few days later in Stage 20. Closure of the eyelids is complete in Stage 23.
分期的人类胚胎描述了导致眼睑形成的发育事件序列。在第四周结束时，视泡靠近表面外胚层。覆盖视泡的表面外胚层因这种接触而增厚，形成晶状体原基（第13阶段）。几天后（约32天，第14阶段），晶状体原基被晶状体凹痕凹陷。再过一两天（约33天，第15阶段），晶状体凹痕闭合：然而，晶状体泡和视杯靠近表面外胚层，似乎挤压着表面。在眼睑发育之前，眼睛上方形成一个小沟或凹槽（眼睑沟），下方也形成一个（第16阶段，37天）。随着这些凹槽加深，在第17 - 19阶段，眼睑褶皱开始发育，首先在眼睛下方，然后在上方。在第19 - 22阶段，眼睑褶皱发育成眼睑，并随着睑裂形成而覆盖更多的眼睛。上眼睑和下眼睑在第19阶段在外眦处会合。内眦在第20阶段几天后形成。眼睑在第23阶段完全闭合。
