We found that the 3-IAA remarkably increased the expression of SP1, a key transcription factor involved in collagen regulation and myopia development, at both mRNA (Fig. 6a) and protein levels (Fig. 6b–e), whereas 3-IAA treatment had no obvious effect on the mRNA expression of other regulators: SP3, SMADs, c-JUN, etc., in HFSFs (Fig. 6a). Here, SP3 is linked to myopia.