ACTA1 and open-angle glaucoma: TGF‐β1 induces a myofibroblast‐like phenotype in human TM cells, as reflected by a dose‐dependent increase in the expression and production of α‐smooth muscle actin (αSMA) in vitro.35 αSMA‐positive human TM cells are spindle shaped and contain stress fibres, signifying an increase in contractility and decrease in out‐flow facility.35 Altered actin cytoskeletal fibres have also been shown to play a crucial role in pathogenesis of POAG and steroid‐induced glaucoma.36 Contrary to the previous findings, Robertson et al28 found that adenoviral transfer of active TGF‐β1 led to decreased αSMA.