Human retinal organoids grown from embryonic stem cells reveal that our blue-light-detecting cells develop first, followed by the red- and green-light-detecting cells. Levels of thyroid hormone act as the molecular switch that spurs development and differentiation of the red and green color-sensing cells, researchers reported yesterday (October 11) in Science. The finding may help scientists better understand why preterm babies, who have less exposure to the hormone because they spend less time in the womb, have higher risks of vision disorders.
K.C. Eldred et al., “Thyroid hormone signaling specifies cone subtypes in human retinal organoids,” Science, 362:eaau6348, 2018.